Skip to content
KickTyres
Audi1995–2024 Critical issues documented

Audi A4 B9: common faults & what to check

The B9 is the Audi A4 built 2016 onward. It was sold here with the 2.0 TFSI, 2.0 TDI, and 2.9 twin-turbo (RS4). Of the 45 faults documented for the A4, 15 apply to this generation, each with its symptoms, what to inspect and a typical repair cost. Free, no account needed.

Check this exact Audi A4

  • Odometer history
  • Money owing
  • Reported stolen
  • Ownership history
  • Official NZ vehicle register data
  • NZ owned and operated

Type the plate for the free basics. The full record is a paid check from $13.49, one car at a time, no subscription.

No NZ plate yet, or buying in Australia? Pick the generation and engine and start a free check below. New to KickTyres? How the check works →

45

Documented faults

Critical

Most serious

$600–$3,000

Typical repair

31

Service milestones

You're looking at the B9

3 engine variants are documented for this generation. Pick yours to narrow further, or keep reading for the generation as a whole.

Choose a different generation

Now narrow it to the engine

A 1.8 and a 2.4 of the same car do not fail the same way, so the faults below narrow to the engine as well as the year. Free, no account needed.

A 2017 Audi A4 is the B9 generation (2016 to now).

Start your free check on this Audi A4

No plate needed. You get the risk score, the buyer's checklist and the guided inspection for the exact car you picked above — not the whole nameplate.

Audi A4 B9Engine not picked yet

Pick the engine above first: the A4 came with 3, and without it the report has to show all of their faults. Pick the engine

Free. The paid plate check is separate, and stays optional.

Can't confirm for this car

Audi A4 · 2017

Narrowed to the year. No engine is recorded for this vehicle. Pick an engine to see which faults apply.

Tell us the engine, or check the engine code on the car, before relying on this.

  • No engine is recorded for this vehicle.

matched on year only

What to look out for

The checks worth doing on a Audi A4 before you hand over any money. Every documented fault is listed below, each with its own page.

  • Common issue

    Test the battery with a proper conductance tester (not just a voltage check) — the result should show state of health above 75%.

    See why

    12V AGM Battery Premature Failure and BMS Coding Fault

    The B9 A4 carries a large number of always-on control modules that impose a significant parasitic drain, causing the OEM AGM start-stop battery (located in the boot) to fail within 3–4 years in typical ownership. The Battery Management System (BMS) controller must be coded to the exact replacement battery specification via VCDS or dealer tooling — fitting a replacement without coding leaves the BMS charging on an incorrect profile, shortening the new battery's life significantly and preventing the start-stop system from re-enabling.

    What you would notice

    • Slow or laboured cold cranking with a healthy engine
    • Start-stop system permanently deactivated without a driver-initiated reason
    • MMI infotainment system resetting or freezing after a cold overnight soak
    • Central locking and comfort window operation intermittently failing
    • Battery or electrical system warning light on the instrument cluster

    Typically $380–$750 to put right.

Audi A4 service schedule

The 2 engines a 2017 Audi A4 was sold with, each with its own intervals. Pick your engine above to narrow this to one. These are the model’s intervals — the car’s own service book is the only thing that can tell you what has actually been done to it.

B9 · 2016–2023 · 3.0 TDI (3.0L V6 Turbo Diesel) - Quattro/Performance Diesel

Diesel

Due by distance

  1. 80,000 km

    Major transmission fluid flush and filter change to keep the S-tronic shifting crisp.

  2. 120,000 km

    Thoroughly inspect the auxiliary drive belt and tensioner assembly, which often see fatigue around this mark.

  3. 150,000 km

    The DPF and EGT sensors may reach their functional limit, depending on short city trips versus long motorway cruising.

B9 · 2016–2023 · 2.0 TFSI (2.0L Turbo) - 40 TFSI/Sport

Petrol

Due by distance

  1. 60,000 km

    The S-tronic transmission oil and filter should be replaced here for longevity.

  2. 90,000 km

    Spark plugs should be replaced, plus a thorough inspection of the water pump and thermostat housing.

  3. 120,000 km

    Inspect suspension bushings and mounts for natural wear.

See all 15 issues for this oneDocumented for the exact year and engine you picked, including 2 rated critical.
Electrical1

0112V AGM Battery Premature Failure and BMS Coding Fault

Test the battery with a proper conductance tester (not just a voltage check) — the result should show state of health above 75%.2015 onwardElectrical
CommonElectrical $380–$750 to fix

The B9 A4 carries a large number of always-on control modules that impose a significant parasitic drain, causing the OEM AGM start-stop battery (located in the boot) to fail within 3–4 years in typical ownership. The Battery Management System (BMS) controller must be coded to the exact replacement battery specification via VCDS or dealer tooling — fitting a replacement without coding leaves the BMS charging on an incorrect profile, shortening the new battery's life significantly and preventing the start-stop system from re-enabling.

Symptoms to notice

  • Slow or laboured cold cranking with a healthy engine
  • Start-stop system permanently deactivated without a driver-initiated reason
  • MMI infotainment system resetting or freezing after a cold overnight soak
  • Central locking and comfort window operation intermittently failing
  • Battery or electrical system warning light on the instrument cluster

What to check

  1. Test the battery with a proper conductance tester (not just a voltage check) — the result should show state of health above 75%.
  2. Confirm the start-stop system activates: if it is permanently suppressed with no fault explanation, assume the battery is weak or uncoded.
  3. Scan the BMS controller for battery age, charge cycle count, and replacement history.

Where to look: Boot/trunk — battery mounted under the floor panel on the right side

Parts involved: 12V battery.

Ask the seller

  • “Has the 12V battery ever been replaced, and if so was it coded to the car using dealer or VCDS tooling?”
  • “Is the start-stop system currently functioning, or is it permanently disabled?”
  • “Has the car ever had difficulty starting overnight or after sitting for a few days?”
Depends on the exact engine — 14 moreDocumented for a specific engine we could not confirm from what you picked. Check the engine code on the car.
Engine, transmission & cooling13

01EA888 Gen3 2.0 TFSI piston ring oil consumption

Check dipstick oil level at purchase and compare after a 20-minute test drive under load.petrol2015 onwardEngineRead the full fault: symptoms, where to look, what to ask the seller

02EA888 Gen4 (CVNA) Excessive Oil Consumption

Pull the dipstick and compare level against the last service record date.petrol2015 onwardEngine
CommonEngine $2,800–$9,000 to fix

Can't confirm for this car

The CVNA EA888 Gen4 2.0 TFSI piston rings and valve stem seals allow oil to pass into the combustion chamber at an accelerated rate. Owners consistently report consumption of 0.5–1.5 litres per 1,000 km, often exceeding Audi's own published tolerance of 0.5 L/1,000 km. Residual carbon from burned oil fouls spark plugs and catalytic converters, adding further repair costs.

Symptoms to notice

  • Blue or grey smoke from exhaust on hard acceleration or engine overrun
  • Oil level noticeably low between scheduled services
  • Frequent low oil level warnings on the dashboard
  • Fouled or oil-coated spark plugs found on inspection
  • Burnt oil smell from exhaust during normal driving

What to check

  1. Pull the dipstick and compare level against the last service record date.
  2. Ask to idle the engine then rev it sharply — blue-tinged smoke on the overrun indicates ring or valve stem seal wear.
  3. Request any oil consumption test results from a dealer or workshop.

Where to look: Engine block — piston rings and valve stem seals, cylinder head

Parts involved: Catalytic converter.

Ask the seller

  • “Has the oil ever needed topping up between scheduled service intervals, and if so how often?”
  • “Has a dealer or independent workshop ever performed a formal oil consumption test on this car?”
  • “Have the spark plugs been replaced more frequently than the recommended schedule due to oil fouling?”

03DETA 2.0 TDI EGR Cooler Failure and Coolant Loss

Check the coolant expansion tank level against recent records — any unexplained drop warrants investigation.diesel2015–2022CoolingRead the full fault: symptoms, where to look, what to ask the seller

042.0 TDI (EA288) EGR and DPF blockage on short-run cars (B9)

Ask what kind of driving the car has done — mostly motorway is good, school-run only is a red flag.diesel2016 onwardEngine
OccasionalEngine $800–$4,500 to fix

Can't confirm for this car

B9 diesels driven mainly around town clog the EGR valve/cooler and diesel particulate filter, causing limp mode and failed regenerations. The EA288 is otherwise durable, but an EGR cooler and DPF clean or replacement together can exceed $4,000 at Euro parts prices. City-driven ex-lease cars are the risk profile.

Symptoms to notice

  • DPF warning light
  • Limp mode with reduced power
  • Frequent active regenerations (hot smell, raised idle)
  • Rough idle from sticking EGR

What to check

  1. Ask what kind of driving the car has done — mostly motorway is good, school-run only is a red flag.
  2. Have a workshop read DPF ash/soot load via diagnostics before purchase.
  3. Check for EGR fault codes.

Where to look: Exhaust after-treatment (DPF under the floor) and EGR on the engine

Parts involved: Diesel particulate filter, EGR valve.

Ask the seller

  • “What percentage of driving is open-road?”
  • “Has the DPF or EGR ever been cleaned or replaced?”

05Water pump internal seal failure, coolant into vacuum system (3.0 TFSI EA839 V6 turbo, B9 A4 and S4)

With the engine cold, check the coolant expansion tank is at the correct level and not freshly topped up.petrol2017–2024CoolingRead the full fault: symptoms, where to look, what to ask the seller

06EA888 TFSI High-Pressure Fuel Pump Cam Follower Wear

Scan the ECU for stored fuel rail pressure faults (P0087, P0190, P0191).petrol2015–2020Engine
OccasionalEngine $320–$4,200 to fix

Can't confirm for this car

The mechanical high-pressure fuel pump on the EA888 TFSI is driven by a dedicated eccentric lobe on the intake camshaft through a steel roller cam follower. The follower wears prematurely, generating metal debris that circulates through the engine oil and fuel system. As the follower cup wears flat, the pump stroke shortens, rail pressure drops, and the engine exhibits hard starting, stalling, and injector damage from contaminated fuel.

Symptoms to notice

  • Hard starting especially when the engine is at operating temperature
  • Engine stalling at idle or low load after warm-up
  • Fuel rail low-pressure fault codes (P0087, P0190) stored in the ECU
  • Loss of power under sustained acceleration
  • Rough or hunting idle that clears at higher RPM

What to check

  1. Scan the ECU for stored fuel rail pressure faults (P0087, P0190, P0191).
  2. Check the engine oil for a metallic sheen or gritty texture if oil change is overdue.
  3. If a workshop inspection is possible: Remove the HPFP from its mounting (a straightforward 3-bolt job) and inspect the cam follower underneath — the roller surface should be smooth and uniform with no flat spot, scoring, or pitting.

Where to look: Top of engine on the intake camshaft — HPFP mounted on the camshaft carrier

Parts involved: High-pressure fuel pump.

Ask the seller

  • “Has the high-pressure fuel pump or cam follower ever been inspected or replaced?”
  • “Has the engine ever been hard to start when warm, or stalled unexpectedly?”
  • “Are there any stored or cleared fault codes related to fuel pressure in the service history?”

072.0 TDI DPF Blockage and Failure

Inspect for any DPF warning or regeneration fault codes (P2002, P2453, P246C).diesel2008 onwardEngine
CommonEngine $800–$3,500 to fix

Can't confirm for this car

The diesel particulate filter on CAHA, CGKA, and DCYA 2.0 TDI engines requires periodic active regeneration at exhaust temperatures above 550°C, achievable only during sustained highway driving. Short-trip urban use in NZ and Australian cities prevents regeneration, leading to progressive soot loading. A fully blocked DPF triggers reduced-power limp mode. Repeated forced regenerations or removal attempts damage the filter substrate. Replacement DPF units are expensive, and downstream oxygen sensor and EGR system damage often accompanies a failed filter.

Symptoms to notice

  • DPF warning light or glow plug warning flashing
  • Reduced power or limp-home mode
  • Excessive fuel dilution of engine oil (diesel smell from dipstick)
  • Failed or interrupted DPF regeneration cycles visible in live data

What to check

  1. Inspect for any DPF warning or regeneration fault codes (P2002, P2453, P246C).
  2. Ask the seller about typical driving patterns — predominantly city use is a red flag.
  3. Check oil for diesel dilution smell.
  4. Confirm DPF has not been removed or blanked (illegal in NZ/AU and can trigger ongoing faults).
  5. If a workshop inspection is possible: Connect a scan tool and check DPF soot load percentage and ash load.

Where to look: Exhaust system, downstream of turbocharger under vehicle floor

Parts involved: Diesel particulate filter.

Ask the seller

  • “Has the DPF ever been cleaned, regenerated professionally, or replaced?”
  • “What is the typical driving pattern — mainly city or highway?”
  • “Is the DPF physically present and confirmed by workshop inspection?”

082.0 TDI EGR System Carbon Buildup

Check EGR cooler for external coolant staining.diesel2008 onwardEngineRead the full fault: symptoms, where to look, what to ask the seller

09EA888 Gen3 water pump / thermostat module coolant leaks (B9)

Check coolant level cold and inspect the block below the water pump for pink staining.petrol2016–2022Cooling
CommonCooling $800–$1,600 to fix

Can't confirm for this car

B9 2.0 TFSI engines carry over the composite water pump and thermostat module that cracks and leaks, usually from 60,000-100,000 km. Audi has revised the part multiple times. Left alone it progresses from slow coolant loss to overheating; access is tight so labour dominates the bill.

An annotated photograph of an automotive engine thermostat identifying the wax capsule and both disc valves.Example of the part — not this vehicle

A double-valve engine thermostat, labelled: the wax capsule is what sticks.

Dougsim · CC BY-SA 3.0 · Wikimedia Commons

Symptoms to notice

  • Low coolant warnings
  • Coolant smell after parking
  • Dried pink residue under the pump
  • Fluctuating temperature gauge

What to check

  1. Check coolant level cold and inspect the block below the water pump for pink staining.
  2. Ask if the pump has already been done with the latest revision part — on higher-km cars a recent replacement is a plus.

Where to look: Water pump/thermostat module on the engine block, right side

Parts involved: Water pump, Thermostat.

Ask the seller

  • “Has the water pump/thermostat module been replaced, and with which revision?”
  • “Any history of coolant top-ups?”

10Intake Valve Carbon Buildup (EA888 Direct Injection)

Ask specifically whether an intake valve carbon clean has ever been performed.petrol2015 onwardEngine
Very commonEngine $600–$1,500 to fix

Can't confirm for this car

Because the EA888 uses gasoline direct injection without a supplementary port injection circuit, fuel never passes over the intake valves and cannot clean them. Oil vapour from the crankcase ventilation system condenses and bakes onto the back of the intake valves, building hard carbon deposits that progressively restrict airflow into the cylinders. Beyond approximately 80,000 km without intervention, the restriction is sufficient to cause rough idle, cold-start misfires, and measurable power loss.

Symptoms to notice

  • Rough or lumpy idle particularly when the engine is cold
  • Misfires at light throttle or during warm-up (P030x codes)
  • Hesitation or stumble on low-RPM light load driving
  • Slightly increased fuel consumption compared with earlier in ownership
  • Poor throttle response that worsens progressively over months

What to check

Ask specifically whether an intake valve carbon clean has ever been performed. If the car has exceeded 80,000 km with no documented clean, budget for the service. If a workshop inspection is possible: On a borescope inserted through the intake manifold runners, the back of the valves should appear clean and metallic — any grey-black crusty coating is carbon buildup.

Where to look: Intake ports and back of inlet valves inside the cylinder head

Parts involved: PCV / oil separator.

Ask the seller

  • “Has an intake valve carbon cleaning service (walnut blasting) ever been performed, and at what mileage?”
  • “Has the car ever had rough idle or misfire issues that were attributed to carbon or fuel delivery?”
  • “What brand and specification of engine oil has been used, as low-quality oil worsens PCV vapour contamination?”

11S-Tronic DL501 Mechatronic Unit Failure

Test drive in slow stop-start traffic and note any shuddering when pulling away from rest.2008 onwardTransmissionRead the full fault: symptoms, where to look, what to ask the seller

12S-tronic DL382 7-Speed Selector Fork and Clutch Pack Wear

2016 onwardTransmissionRead the full fault: symptoms, where to look, what to ask the seller

13DL382 7-speed S tronic low-speed shunt and clutch shudder (B9)

Creep in traffic and do slow uphill starts on the test drive.petrol2016 onwardTransmission
OccasionalTransmission $400–$4,000 to fix

Can't confirm for this car

The B9's DL382 wet-clutch S tronic is more reliable than the old DL501 but is widely reported to shunt and hesitate in stop-start traffic, with some cars developing clutch shudder and a few needing mechatronic work. Software updates improved calibration. Mostly a refinement complaint, but genuine shudder on take-off means clutch work.

Symptoms to notice

  • Jerky low-speed take-up
  • Shudder on light-throttle hill starts
  • Delayed engagement from park

What to check

Creep in traffic and do slow uphill starts on the test drive. Ask if gearbox software updates have been applied and when the S tronic oil was last serviced (60,000 km).

Where to look: Transmission

Parts involved: Clutch.

Ask the seller

  • “Has the gearbox software been updated?”
  • “Any shudder pulling away when warm?”
Electrical1

01Belt starter-alternator water entry and fire risk recall 27H2 (2.0 TFSI mild hybrid MHEV petrol, B9 A4, 2017-2020)

Ask for Audi paperwork showing campaign 27H2 was done, or have an Audi dealer check the VIN for open recalls.petrol2017–2020Electrical
OccasionalElectrical $0–$2,500 to fix

Can't confirm for this car

On B9 A4 models with the 2.0 TFSI petrol engine and 12 volt mild hybrid (MHEV) system built from May 2017 to March 2020, moisture can get into a gap in the belt starter-alternator housing and make it overheat, with a risk of fire (Australian recall PRA 2020/18379, Audi campaign 27H2). The dealer fix is free. Cars without the mild hybrid system are not affected.

Symptoms to notice

  • Battery or charging warning light
  • Engine start/stop stops working
  • Burning smell from the engine bay

What to check

Ask for Audi paperwork showing campaign 27H2 was done, or have an Audi dealer check the VIN for open recalls. With the bonnet open after a drive, sniff for a burning or electrical smell around the front of the engine, and check no charging or electrical warnings show on the dash. If a workshop inspection is possible: have the starter-alternator and its housing seal inspected and the fault memory read.

Where to look: Belt starter-alternator on the front of the 2.0 TFSI engine

Parts involved: Alternator, Starter motor.

Ask the seller

  • “Is this a 2.0 TFSI mild hybrid, and has recall 27H2 been done?”
  • “Has the charging or battery warning ever come on?”
Other Audi A4 engines and years30 documented issues that do not apply to the one you picked.
Engine, transmission & cooling18

01Multitronic 0AW CVT Chain Slip and Hydraulic Pump Wear

Check transmission fluid change history — fluid must be replaced every 40,000-60,000 km maximum; many are never changed.2008–2010Transmission
OccasionalTransmission $4,500–$12,000 to fix

Does not apply

The Multitronic 0AW CVT uses a steel push-belt chain running between two variable-diameter conical pulley pairs whose clamping force is controlled by a hydraulic pump. The system is acutely sensitive to transmission fluid condition because degraded fluid reduces the coefficient of friction between the chain and pulley faces, allowing micro-slip events. Each slip event generates heat, further degrading fluid and accelerating pulley surface scoring. The internal hydraulic pump also wears over high mileage, reducing maximum clamping pressure and compounding the slip problem. Progressive chain wear causes the characteristic shudder and rev-hang on acceleration. Complete chain or pulley destruction requires full transmission replacement. Many owners and independent workshops treated this as a sealed lifetime unit, accelerating fluid degradation failures.

Symptoms to notice

  • Shuddering or juddering sensation during moderate acceleration
  • Engine revs climbing without proportional vehicle acceleration (chain slip)
  • Transmission warning light
  • Delayed, harsh, or jerky engagement from rest
  • Whining noise from transmission under load at varying speeds

What to check

Check transmission fluid change history — fluid must be replaced every 40,000-60,000 km maximum; many are never changed. On a test drive, accelerate steadily from 40-100 km/h and listen and feel for slip, shudder, or rev-hang. Scan VCDS for Multitronic fault codes and check if latest software calibration updates have been applied. A transmission that has never had a fluid change and shows any slip should be considered a write-off or priced accordingly.

Where to look: Front of vehicle, transaxle unit beneath and behind the engine on FWD models

Parts involved: CVT belt and pulleys.

Ask the seller

  • “Has the Multitronic CVT fluid been changed at the correct intervals and can you show records?”
  • “Has the transmission ever been rebuilt or replaced?”
  • “Does the car shudder, slip, or hesitate under acceleration?”

02EA113 2.0 TFSI Cam Follower Disintegration and HPFP Failure

Scan all ECUs for fuel pressure codes.petrol2004–2012EngineRead the full fault: symptoms, where to look, what to ask the seller

03Multitronic CVT failure (front-wheel-drive B6/B7/B8)

Cold start and immediately drive: shudder or delayed engagement when cold is the classic early sign.2002–2015TransmissionRead the full fault: symptoms, where to look, what to ask the seller

04EA888 Gen1/2 1.8/2.0 TFSI excessive oil consumption (piston rings)

Ask directly how much oil it uses per 1,000 km — under 0.5 L is acceptable, a litre is the fault.petrol2008–2013EngineRead the full fault: symptoms, where to look, what to ask the seller

05CAGA/CJCA 2.0 TDI Cam Follower and HPFP Lobe Wear

diesel2008–2015EngineRead the full fault: symptoms, where to look, what to ask the seller

06EA113 2.0 TFSI Hydraulic Timing Chain Tensioner Failure

The EA113 2.0 TFSI engine uses a hydraulically actuated timing chain tensioner that depends on adequate oil pressure to maintain chain tension.petrol2004–2012EngineRead the full fault: symptoms, where to look, what to ask the seller

07Oil sludge, blocked oil pickup screen and coked turbo oil feed line (1.8T 20v AEB/APU/ANB)

petrol1997–2001EngineRead the full fault: symptoms, where to look, what to ask the seller

081.8T oil sludge and turbo oil starvation (B6)

Pull the oil cap and look inside with a torch — black mayonnaise or baked deposits mean walk away.petrol2001–2005Engine
OccasionalEngine $2,000–$7,000 to fix

Does not apply

The B6 1.8 turbo has a small 3.7-litre sump and tight oil galleries; extended oil intervals cause sludge that blocks the pickup and starves the turbo and cam journals. VW/Audi faced class actions over it in the US and extended warranties (long expired). Twenty years on, survivors are either well-serviced or already rebuilt — a sludged engine needs a turbo, pickup clean-out and sometimes a full rebuild.

Symptoms to notice

  • Oil pressure light at idle when hot
  • Tappet rattle on start-up
  • Whining or smoking turbo
  • Thick black deposits under the oil cap

What to check

  1. Pull the oil cap and look inside with a torch — black mayonnaise or baked deposits mean walk away.
  2. Demand a full service history showing 10,000 km-or-less oil changes with synthetic oil.
  3. Listen for top-end rattle on a cold start.

Where to look: Engine internals — sump, oil pickup, turbo oil feed

Parts involved: Turbocharger.

Ask the seller

  • “Can you show every oil change receipt?”
  • “Has the turbo or oil pickup ever been replaced?”

09EA888 timing chain tensioner failure (B8)

Cold start the car (insist it hasn't been warmed up) and listen for a rattle in the first second.petrol2008–2013Engine
CommonEngine $1,200–$7,000 to fix

Does not apply

Early EA888 engines in the B8 use a ratchet-style timing chain tensioner that can let the chain skip on start-up, bending valves and wrecking the top end. Audi revised the tensioner (updated part from ~2012); un-updated engines are a known gamble. Preventive tensioner replacement is far cheaper than the cylinder head rebuild that follows failure.

The front of a dual overhead camshaft engine with the timing cover removed, exposing the timing chain and sprockets.Example of the part — not this vehicle

The front of a twin-cam engine with the timing cover off — chain, sprockets and guides.

Logansenf · CC BY-SA 4.0 · Wikimedia Commons

Symptoms to notice

  • Death rattle for 1-2 seconds on cold start
  • Engine cranks but won't start after chain skip
  • Timing/camshaft correlation fault codes

What to check

Cold start the car (insist it hasn't been warmed up) and listen for a rattle in the first second. Ask whether the updated tensioner has been fitted — receipts will show the revised part number. A scan for P0016/P0341 codes is cheap insurance.

Where to look: Timing chain cover, rear/side of engine (chain at gearbox end on EA888)

Parts involved: Timing chain.

Ask the seller

  • “Has the timing chain tensioner been updated to the revised version?”
  • “Any rattle on cold start?”

10CAEB/CDNB 2.0 TFSI Timing Chain Tensioner Failure

Cold-start the engine from fully cold and listen immediately at the front of the engine for chain rattle.petrol2008–2015EngineRead the full fault: symptoms, where to look, what to ask the seller

11Timing belt, tensioner and water pump failure on interference engines (1.8T 20v and 2.4/2.8 V6 30v)

Both the B5 1.8T and the 30 valve V6 are interference engines with the water pump, a hydraulic tensioner and rollers on the same timing belt.petrol1996–2001EngineRead the full fault: symptoms, where to look, what to ask the seller

12EA888 Plastic Impeller Water Pump Failure

Check coolant service history and confirm it has been flushed at manufacturer interval.petrol2008–2013CoolingRead the full fault: symptoms, where to look, what to ask the seller

13DL501 (0B5) 7-speed S tronic mechatronic failure (quattro B8)

Drive until the gearbox is fully warm (electronics typically fail hot) and work through low-speed shifts and reverse.2008–2016Transmission
CommonTransmission $3,000–$7,000 to fix

Does not apply

Quattro B8 A4s use the DL501 wet-clutch 7-speed S tronic whose mechatronic unit suffers circuit board and pressure sensor failures — symptoms range from harsh shifts and no reverse to sudden limp mode. Specialist mechatronic repair is possible but the unit is inside the gearbox, so labour is significant. Regular 60,000 km fluid services help but do not prevent the electronic failures.

Symptoms to notice

  • Gearbox warning light / limp mode when hot
  • No reverse gear
  • Harsh clunky shifts 1st-2nd
  • Gear indicator flashing

What to check

  1. Drive until the gearbox is fully warm (electronics typically fail hot) and work through low-speed shifts and reverse.
  2. Ask for S tronic oil service records at 60,000 km intervals and any mechatronic repair invoices.
  3. Scan for stored transmission codes (P17xx series).

Where to look: Transmission — mechatronic unit inside the gearbox

Parts involved: Mechatronic / valve body.

Ask the seller

  • “Has the mechatronic unit ever been repaired or replaced?”
  • “When were the S tronic oil and filter last changed?”

14EA888 Gen 1 Excessive Oil Consumption

Check current oil level and ask when it was last topped up and by how much.petrol2012–2013EngineRead the full fault: symptoms, where to look, what to ask the seller

15HPFP Cam Follower Collapse

Inspect the roller face for scoring, pitting or a shed roller pin.petrol2008–2015EngineRead the full fault: symptoms, where to look, what to ask the seller

162.0 TFSI (B7, EA113) cam follower wear and oil consumption

Ask for cam follower inspection records (30-minute job, should be checked every 40,000 km).petrol2005–2008Engine
CommonEngine $300–$3,000 to fix

Does not apply

The B7 2.0 TFSI shares the EA113 high-pressure fuel pump cam follower wear problem: the follower wears through and damages the camshaft and pump. B7s also commonly develop PCV valve failure and moderate oil consumption. The follower is a cheap periodic replacement, but neglected examples get expensive fast.

Symptoms to notice

  • Ticking from the rear of the engine
  • Fuel pressure/EPC faults
  • Whistling PCV / rough idle
  • Oil top-ups needed between services

What to check

  1. Ask for cam follower inspection records (30-minute job, should be checked every 40,000 km).
  2. Scan for fuel rail pressure codes.
  3. Pull the dipstick and ask how much oil it uses per 1,000 km — more than half a litre needs investigation.

Where to look: Rear of cylinder head under the HPFP; PCV on top of the engine

Parts involved: High-pressure fuel pump, PCV / oil separator.

Ask the seller

  • “When was the cam follower last checked?”
  • “How much oil does it use between services?”

17Electric auxiliary coolant pump overheating, fire-risk recall REC-000020 (A4 2.0 TFSI EA888 petrol)

After a test drive of at least 15 minutes, check the coolant temperature gauge behaviour throughout the drive and after shutdown.petrol2011–2016Cooling
OccasionalCooling $600–$1,800 to fix

Does not apply

On A4 models with the 2.0 TFSI EA888 turbo petrol built from 2011 to early 2017, the electric auxiliary coolant pump that keeps coolant moving through the turbo and heater after shutdown can be blocked by debris in the cooling system or take in moisture, then short circuit and overheat; in the worst case it can smoulder and start a fire. Audi recalled these cars in Australia in 2018 (REC-000020, PRA 2018/16842, campaign 19N3) and replaces the pump free of charge. A failed pump that was not caught by the recall can also let the engine and turbo run hot, so check the recall was done and watch the temperature gauge.

Symptoms to notice

  • Coolant temperature warning light or gauge reading higher than normal operating range
  • Reduced heater output with cold or intermittent air from cabin vents
  • Fault codes for auxiliary coolant pump circuit open or short (P260D or manufacturer-specific code)
  • Overheating warning during or shortly after sustained high-speed or hard driving
  • Absence of the normal electric pump whirring sound from the engine bay during post-shutdown cooling cycle

What to check

After a test drive of at least 15 minutes, check the coolant temperature gauge behaviour throughout the drive and after shutdown. Scan for fault codes relating to the auxiliary water pump circuit. On a warmed engine shortly after shutdown, listen near the firewall area for the auxiliary pump running. Inspect the coolant expansion tank for correct level and absence of oil contamination or rusty discolouration.

Where to look: Engine bay — electric auxiliary coolant pump mounted near the firewall or within the turbocharger cooling circuit

Parts involved: Water pump.

Ask the seller

  • “Has a coolant temperature warning or overheating light ever appeared on this vehicle?”
  • “Has the auxiliary electric coolant pump been inspected or replaced during ownership?”
  • “Has the coolant been flushed and renewed on the manufacturer-recommended schedule?”

18PCV / Oil Separator Valve Failure

Inspect the valve cover oil separator housing for cracks and check the large vacuum hose from valve cover to intake for oil contamination.petrol2008–2015EngineRead the full fault: symptoms, where to look, what to ask the seller
Electrical6

01Front airbag control unit software recall, airbags may not inflate correctly (B8 A4, 2012-2014)

2012–2014Electrical
OccasionalElectrical $0–$300 to fix

Does not apply

B8 A4 sedans and Avants built from November 2011 to October 2014 (all engines) were recalled in Australia because the front airbags may not inflate correctly in a crash (PRA 2014/14402). The fix is a free software update to the airbag control unit at an Audi dealer. A car that missed the recall gives no warning sign, so the only check is the VIN.

Symptoms to notice

  • Usually none: the fault only shows in a crash
  • Airbag warning light is not a reliable sign of this fault

What to check

  1. Ask the seller for Audi service history showing the airbag software recall (PRA 2014/14402) was done, or ring an Audi dealer with the VIN to confirm there are no open recalls.
  2. Check the airbag warning light comes on at start up and then goes out.
  3. If a workshop inspection is possible: have the airbag control unit software level read and compared with the recall release.

Where to look: Airbag control unit, centre of the car under the dash

Ask the seller

  • “Has the airbag software recall been done, and is it on the Audi service record?”
  • “Has an Audi dealer confirmed there are no open recalls on this VIN?”

02Ignition coil pack and ignition module failure causing misfires (1.8T 20v)

Start the engine and watch the dash: the engine light must go out and must never flash on the drive.petrol1997–2001ElectricalRead the full fault: symptoms, where to look, what to ask the seller

03Air conditioning auxiliary heater element overheating recall 80C5 (B8 A4, built April 2011 to May 2015)

Ask for proof that Audi campaign 80C5 (PRA 2018/16956) was done, or have an Audi dealer check the VIN for open recalls.2011–2015Electrical
RareElectrical $0–$800 to fix

Does not apply

The B8 A4 sedan and Avant built from April 2011 to May 2015 (all engines) was recalled in Australia because the electric auxiliary heater element in the heating and air conditioning unit can overheat where it connects, with a risk of smouldering or fire (PRA 2018/16956, Audi campaign 80C5). The repair is free at an Audi dealer. Whether a particular car is affected is decided by its VIN.

Symptoms to notice

  • Burning or hot plastic smell from the vents
  • Heater blowing cold or fan acting up
  • Fuse for the heater blowing

What to check

Ask for proof that Audi campaign 80C5 (PRA 2018/16956) was done, or have an Audi dealer check the VIN for open recalls. With the engine running, set the heater to full hot and sniff the vents for a burning or hot plastic smell, and check warm air arrives quickly. If a workshop inspection is possible: have the dealer confirm the heater element and connector were replaced or checked under the campaign.

Where to look: Electric auxiliary heater element inside the heater and air conditioning box behind the dash

Ask the seller

  • “Has Audi campaign 80C5 for the heater element been done?”
  • “Have you ever smelt burning from the vents?”

04MMI 2G/3G Display and Control Unit Failure

The B8 A4 introduced Audi's MMI (Multi Media Interface) infotainment system in both 2G and 3G hardware generations.2008–2016Electrical
CommonElectrical $400–$2,800 to fix

Does not apply

The B8 A4 introduced Audi's MMI (Multi Media Interface) infotainment system in both 2G and 3G hardware generations. The display module uses a TFT screen with ribbon cable connections that are prone to fatigue cracking from repeated thermal cycling and vibration. Failure typically presents as vertical pixel lines, partial blackouts, or a completely black screen while the audio and navigation systems continue to function (confirming the processor is running but the display has failed). In other cases the control unit itself fails — the MMI becomes unresponsive to inputs, reboots continuously, or loses stored settings after ignition cycles. The 3G MMI navigation hard drive can also fail, causing the satellite navigation to become unavailable while the rest of the unit continues to operate.

Symptoms to notice

  • Vertical or horizontal lines of dead pixels across the display, or a partially or fully black screen while audio continues to play
  • MMI system freezing mid-operation, becoming unresponsive to rotary controller or button inputs
  • Spontaneous MMI reboots — the Audi rings boot screen appears repeatedly during a journey
  • Navigation system unavailable or showing an error message while radio and phone functions continue to operate

What to check

  1. Switch on the ignition and inspect the MMI display for missing pixel columns, discolouration, or partial blackout — these are characteristic of ribbon cable failure.
  2. Cycle through all MMI menus to check for freezing or sluggish response.
  3. Test the navigation system — a failed hard drive will show an error or fail to load maps.
  4. Check that the MMI retains settings (radio stations, navigation home address) after the car is locked and reopened.
  5. Inspect the screen edges for separation or any signs that the unit has been previously opened.

Where to look: Centre stack dashboard (display screen) and boot-mounted MMI control unit/hard drive

Ask the seller

  • “Does the MMI display show any lines, dark patches, or go black at any point?”
  • “Does the MMI ever freeze or reboot itself during a drive?”
  • “Is the satellite navigation fully functional, including map loading?”

05Instrument cluster display missing pixels (B5 centre LCD)

1995–2001Electrical
Very commonElectrical $250–$700 to fix

Does not apply

The LCD display in the middle of the B5 instrument cluster, which shows the odometer, trip computer and warning information, commonly loses pixels or whole rows because the bonded ribbon connection to the circuit board fails. It starts with a few blank segments and gets worse until the display is unreadable, which can hide the odometer reading and warning messages. It is fixed by fitting a new LCD and ribbon at a cluster repair specialist.

Symptoms to notice

  • Missing lines or segments in the centre display
  • Odometer or trip numbers hard to read
  • Display fading or going blank when cold
  • Warning messages unreadable

What to check

Turn the ignition on and look closely at the centre display between the speedo and tacho: every digit of the odometer and trip meter should be complete with no blank lines or dead rows. Check it again after the drive once the cabin temperature has changed. If the odometer is unreadable, compare the km in the service book and the latest WOF sheet to confirm the true mileage. If a workshop inspection is possible: use a scan tool to run the cluster self test, which lights every segment so missing pixels are obvious.

Where to look: Centre LCD in the instrument cluster behind the steering wheel

Ask the seller

  • “Has the cluster display been repaired or the cluster replaced?”
  • “If the cluster was replaced, was the odometer reading carried over?”

06Seat belt warning may not sound continuously, software recall REC-001650 (B9 A4, 2018-2021)

Ask for proof that Audi campaign 90P5 was done or have an Audi dealer check the VIN.2018–2021Electrical
CommonElectrical $0–$200 to fix

Does not apply

2018 to 2021 B9 A4 models (all engines) were recalled in Australia because the unbuckled seat belt warning may only sound now and then instead of continuously, so an unbelted occupant can go unnoticed (REC-001650, Audi campaign 90P5). The fix is a free software update at an Audi dealer.

Symptoms to notice

  • Seat belt chime stops or comes and goes while a front belt is unbuckled

What to check

Ask for proof that Audi campaign 90P5 was done or have an Audi dealer check the VIN. During the test drive, with a passenger seated and their belt left unbuckled for a moment at low speed in a safe place, check the warning stays on continuously. If a workshop inspection is possible: have the dealer confirm the control unit software is at the recall level.

Where to look: Instrument cluster and seat belt warning software

Ask the seller

  • “Has the seat belt warning software recall been done?”
Body, brakes, suspension & interior4

01Rear axle nuts may break, recall REC-001665 and follow-up REC-005076 (B9 A4, 2019-2021, check VIN)

Ask for Audi paperwork showing campaigns 42L1 and 42L5 were done, or have an Audi dealer check the VIN for open recalls.2019–2021Suspension
OccasionalSuspension $0–$600 to fix

Does not apply

On 2019 to 2021 B9 A4 models (all engines) the nuts that clamp the rear axle assembly may not meet specification and can break, which can let the rear axle move suddenly (Australian recall REC-001665, Audi campaign 42L1). A follow-up recall (REC-005076, campaign 42L5) checks rear axle alignment on cars whose nuts were replaced, because misalignment can cause fast tyre wear and sudden flat tyres. Both are free at an Audi dealer.

Symptoms to notice

  • Clunk or knock from the rear over bumps
  • Car pulls or the rear feels loose
  • Uneven or very fast wear on the inside of the rear tyres

What to check

  1. Ask for Audi paperwork showing campaigns 42L1 and 42L5 were done, or have an Audi dealer check the VIN for open recalls.
  2. Look at the rear tyres for wear on the inner edges, and on the test drive listen for knocks from the rear and check the car tracks straight.
  3. If a workshop inspection is possible: have the rear axle clamping nuts inspected and a four wheel alignment check done.

Where to look: Rear axle assembly and its clamping nuts under the back of the car

Ask the seller

  • “Have the rear axle nut recall and the follow-up alignment recall both been done?”
  • “Have the rear tyres worn out unusually fast?”

02B5 front multi-link upper control arm ball joint and bush wear

On the test drive, go slowly over speed bumps and into a driveway with the window down and listen for clunks or knocks from the front.1995–2001SuspensionRead the full fault: symptoms, where to look, what to ask the seller

03Rear Subframe Bush Deterioration

During a test drive, note whether the rear of the car tramlines, wanders, or feels unsettled over undulations and during braking from speed.2001–2016SuspensionRead the full fault: symptoms, where to look, what to ask the seller

04Front Lower Control Arm Ball Joint and Bush Wear

Inspect the front control arm bushes visually for splitting, tearing, or separation of the rubber from the steel insert.2001–2016Suspension
Very commonSuspension $550–$1,900 to fix

Does not apply

The front suspension on B6, B7, and B8 A4 models uses aluminium lower control arms (wishbones) with pressed-in rubber-bonded bushes and an integral ball joint at the outboard end. Both the front bush and the ball joint wear faster than expected on these arms, particularly on vehicles used in urban driving with frequent low-speed cornering and kerbing. On OEM control arms, the ball joint cannot be replaced separately — once the ball joint wears beyond limits, the entire control arm must be replaced. The front bush deteriorates under load cycling and can allow the arm to move fore-aft, degrading steering response and causing tyre wear. Worn ball joints, if left uncorrected, eventually develop enough play to separate under load, causing sudden loss of front-wheel steering geometry control.

The front wheel of a car splayed outward with the lower control arm hanging down after a ball joint separation.Example of the part — not this vehicle

A separated lower ball joint: the control arm has dropped and the wheel has splayed out under the guard.

Elfix · CC0 · Wikimedia Commons

Symptoms to notice

  • Clunking or knocking from the front suspension when driving over potholes, speed bumps, or rough road surfaces
  • Vague or imprecise steering, particularly on initial turn-in, caused by front bush deflection under load
  • Uneven tyre wear across the front axle, often showing greater wear on the inner or outer shoulder
  • Steering pulling to one side under hard braking, suggesting one side is worn more than the other

What to check

Inspect the front control arm bushes visually for splitting, tearing, or separation of the rubber from the steel insert. During the test drive, note any clunking from the front suspension over speed bumps or rough surfaces, or vagueness in the steering on turn-in. Check front tyre wear — uneven wear across the tread width can indicate compromised control arm geometry. If a workshop inspection is possible: Have the car raised on a hoist and grip the front tyre at 12 and 6 o'clock to check for play in the ball joint — any detectable movement indicates replacement is needed.

Where to look: Front lower control arms, one per side — ball joint at the wheel hub end, bushes at the subframe end

Parts involved: Ball joint.

Ask the seller

  • “Have the front control arms or ball joints been replaced? At what mileage?”
  • “Has the car ever clunked from the front over bumps or speed humps?”
  • “When was the last wheel alignment performed, and were any suspension faults noted?”
Fluid leaks2

012.0 TDI Injector Fuel Return Pipe Cracking and Diesel Contamination

Inspect the fuel return pipes across the top of the engine for cracks, brittleness, or staining.diesel2004–2014Fluid LeaksRead the full fault: symptoms, where to look, what to ask the seller

02Cam chain tensioner gasket and valve cover gasket oil leaks (2.4/2.8 V6 30v)

With a phone torch, look along both sides of the V6 where the valve covers meet the heads and at the front of each head for wet, dark oil or grime.petrol1996–2001Fluid LeaksRead the full fault: symptoms, where to look, what to ask the seller

Audi A4 faults in detail

Narrowed to the Audi A4 · 2017. Each of these has its own page: the symptoms, where to look, what to ask the seller and what the repair costs. Free, no account needed.

2.0 TDI EGR System Carbon BuildupMajor · EngineDETA 2.0 TDI EGR Cooler Failure and Coolant LossMajor · CoolingEA888 Gen3 2.0 TFSI piston ring oil consumptionMajor · EngineS-tronic DL382 7-Speed Selector Fork and Clutch Pack WearMajor · TransmissionS-Tronic DL501 Mechatronic Unit FailureCritical · TransmissionWater pump internal seal failure, coolant into vacuum system (3.0 TFSI EA839 V6 turbo, B9 A4 and S4)Major · Cooling

What these repairs cost on other cars

Some of the Audi A4’s documented faults are repairs other models share. Each page lists the documented NZ cost for every model it affects.

Other Audi models

Audi A343 documented faultsAudi A634 documented faultsAudi A525 documented faultsAudi Q520 documented faultsAudi S318 documented faultsAudi TT17 documented faults

Audi A4 buyer questions

Is the Audi A4 reliable?

Like any used car, it depends on the specific example and its service history. Across the 45 documented faults for the Audi A4, the recurring problem areas are transmission, engine, and electrical. A Audi A4 with a full service history and no signs of the issues listed on this page can be a sound buy but each one needs to be checked individually before you commit.

What are the most common problems with a used Audi A4?

We've catalogued 45 known faults for the Audi A4, covering transmission, engine, and electrical. All 45 are written out in full on this page, with the symptoms to notice, what to inspect, and typical repair costs for each. Free to read, no account needed.

How much do repairs cost on a Audi A4?

Most single repairs on the Audi A4 fall between $600–$3,000 at NZ independent-workshop rates. Some of the 45 documented faults cost less and a few cost considerably more, and no one car needs them all. Knowing which ones to look for before you view is what lets you negotiate the price down or walk away.

Should I get a pre-purchase inspection on a Audi A4?

Yes. A Audi A4 inspection focused on its known weak points is the single best way to avoid an expensive mistake. KickTyres gives you a guided, model-specific inspection plus a market valuation and negotiation figure for $24.90 far less than the cost of missing one of the faults on this page.