Mazda CX-5: common faults & what to check

Symptoms to notice

• Persistent ticking or tapping noise from the cylinder head at idle, worse when cold
• Low oil pressure warning lamp illuminating
• Sudden loss of engine power or an engine that stops without warning
• Metallic grey debris visible at the oil filler cap or on the dipstick
• Vacuum brake booster losing assistance due to pump driven off the worn camshaft

What to check

1. 1.Ask for documented evidence of TSB R073/15 camshaft inspection at a Mazda dealer.
2. 2.Listen for persistent ticking or tapping at idle that worsens when cold.
3. 3.On any pre-2019 diesel CX-5 above 80,000 km, insist on a pre-purchase Mazda dealer inspection before committing.
4. 4.Remove the oil filler cap and look for metallic debris or a grey metallic sheen in the oil.

Symptoms to notice

• Turbo whine or bearing noise under acceleration, distinct from normal turbo spool sound
• Blue-grey smoke from exhaust under boost or on deceleration and throttle lift
• Oil consumption without any visible external leak
• Check engine light or boost-pressure-related fault codes
• Reduced power and flat acceleration compared to a healthy 2.5T

What to check

1. 1.Review service history for strict oil change intervals — the 2.5T requires quality full-synthetic oil changed at or below 10,000 km.
2. 2.Check for oil consumption by reviewing the dipstick.
3. 3.Listen for turbo bearing noise under a sustained boost test drive.
4. 4.Check for blue smoke in mirrors when lifting off after acceleration.
5. 5.If a workshop inspection is possible: Remove and inspect the turbo oil feed banjo bolt restrictor orifice for carbon deposit blockage.

Symptoms to notice

• Hard or extended cranking required to start when engine is warm
• Stalling at idle, especially after a hot restart
• P0087 fuel rail or system pressure too low fault code
• Rough or lumpy running under moderate throttle load
• Reduced engine power
• Possible injector-related secondary fault codes if pressure deficit is prolonged

What to check

1. 1.Scan ECU for P0087 and related fuel pressure fault codes, including freeze frame data.
2. 2.Check live fuel rail pressure with diagnostic equipment during cranking and at idle.
3. 3.Inspect pump drive coupling and camshaft drive area for wear debris.
4. 4.Review any history of hard starting complaints or fuel system work.

Symptoms to notice

• Diesel knock or metallic ticking audible around the cylinder head on cold start
• Visible carbon soot streaks radiating from base of one or more injectors
• Rough idle or single-cylinder misfire that worsens when cold
• Diesel or exhaust odour from engine bay under the bonnet

What to check

With the engine cold and the intake ducting removed, visually inspect the base of each injector for carbon tracking, black soot streaks, or oily carbon deposits on the cylinder head surface. Remove injector hold-down clamps and inspect for evidence of blow-by residue under the clamp. Service history showing injector copper washers replaced at high mileage is a positive sign. Vehicles over 120,000km without documented injector work are highest risk.

Symptoms to notice

• Oil level on dipstick rising above maximum between service intervals
• Strong diesel odour when engine oil cap is removed or dipstick is pulled
• Thin, pale-coloured oil on dipstick that smears without resistance
• White or blue-grey smoke from exhaust on startup after the vehicle has sat overnight

What to check

1. 1.Remove oil dipstick and check for a rising oil level, thin consistency, or diesel odour.
2. 2.Inspect the injector return pipe assembly visible on top of the camshaft cover for cracks, weeping, or staining.
3. 3.Check for a low-grade fuel smell in the engine bay with the bonnet open after a cold start.

Symptoms to notice

• Oil level above the upper mark or X mark on the dipstick
• Oil smells of diesel or looks thin
• Oil or engine warning light
• Frequent DPF regeneration (fan running, idle raised after switch-off)

What to check

1. 1.Pull the dipstick: oil above the upper mark or X mark, or oil that smells of diesel, is a warning sign.
2. 2.Ask how the car was used (short trips) and whether the DPF software update and oil changes were done on time.
3. 3.Check the dash for oil or engine warning lights.
4. 4.If a workshop inspection is possible: scan for DPF and oil dilution codes, read the oil dilution value, and consider an oil analysis.

Symptoms to notice

• Misfire or rough running
• Ticking or tapping from the top of the engine
• Check engine light
• Loss of power or stall

What to check

At the viewing, ask for the recall completion record or dealer service history showing the recall was done, and give the VIN to a Mazda dealer to check whether the recall is still open. Listen at idle and while driving gently at light throttle for ticking, tapping or a misfire, and watch for the check engine light. On the test drive, cruise at steady light throttle (where cylinder deactivation works) and feel for stumbling or loss of power. If a workshop inspection is possible: scan for misfire codes and confirm the PCM software is at the recall level; a rocker that has already dropped needs the cam cover off.

Symptoms to notice

• P0299 underboost fault code with noticeable lack of power under hard acceleration
• Engine entering limp mode during brisk acceleration
• Excessive black or grey smoke from the exhaust under load
• Surging or inconsistent power delivery at partial throttle
• Wheeze, whistle, or lack of a clean progressive spool sound from the turbocharger

What to check

During a test drive, accelerate briskly from low revs through the full rev range and verify consistent, smooth boost build without flat-spots or surging. On vehicles with a documented EGR soot history or high mileage, treat the turbocharger VGT mechanism as requiring inspection before purchase. If a workshop inspection is possible: Connect an OBD scanner and check for P0299 (underboost) fault codes.

Symptoms to notice

• Shudder or vibration sensation during slow-speed tight turning manoeuvres
• AWD system warning light illuminated on the instrument cluster
• Clicking or grinding sensation from the rear axle area under cornering load
• Burning smell from the rear of the vehicle after low-speed manoeuvring

What to check

1. 1.Locate the rear coupling unit filler plug on the coupling housing and check fluid condition — correct fluid is clear to amber and should not be black, metallic, or have a burnt odour.
2. 2.Scan for AWD-related fault codes such as C1A44 or C1A46.
3. 3.Conduct a tight low-speed turning road test in a car park and feel for shudder through the drivetrain.
4. 4.Inspect the coupling unit perimeter for oil weeping around the input/output flange seals.
5. 5.Ask for coupling fluid change records.

Symptoms to notice

• White smoke from exhaust on startup and white chalky deposits in the EGR bore
• Coolant level dropping without a visible external leak

What to check

Check for white chalky deposits inside the EGR valve bore. Perform a combustion gas test on the coolant. White smoke on startup in a warm climate is characteristic.

Symptoms to notice

• Amber DPF warning light illuminated on the dashboard, sometimes cycling on and off
• Noticeable loss of power and restricted throttle response (limp mode) during DPF blockage events
• Increased fuel consumption as the ECU attempts repeated active regeneration cycles
• Excessive white or acrid smoke from exhaust during a forced active regeneration

What to check

1. 1.Look for an illuminated DPF warning light or amber engine management light on the instrument cluster.
2. 2.Ask the seller about typical trip length — predominantly urban/short trips indicate high risk.
3. 3.If a workshop inspection is possible: Using an OBD-II scanner with live data, check DPF soot load percentage and differential pressure across the filter.

Symptoms to notice

• Blue or grey smoke on cold start or after prolonged idle
• Oil level noticeably dropping between standard service intervals
• Oil-fouled or oil-wet spark plugs on inspection
• Slight oil residue around intake manifold or PCV hose connections
• Oil consumption exceeding 1 litre per 5,000 km

What to check

1. 1.Check oil level against documented service history and calculate consumption rate.
2. 2.Inspect spark plugs for oil contamination.
3. 3.Cold-start observation for blue exhaust smoke.
4. 4.Check PCV system and breather hoses for oil residue.
5. 5.Ask for Mazda dealer oil consumption test records if available.

Symptoms to notice

• Metallic rattling noise from front of engine on cold start, clearing within 5-15 seconds
• Check engine light with camshaft or crankshaft position timing codes P0016 or P0017
• Rough running or hesitation immediately after cold start before rattle clears
• Elevated oil consumption on affected units with worn tensioners

What to check

Cold-start the engine and listen for a metallic rattle from the front or top of the engine block. The rattle should disappear within seconds as oil pressure builds — if it persists beyond 10 seconds, the tensioner is likely worn. Review service history closely for oil change adherence, as extended intervals are the primary driver of early tensioner wear. Scan for stored P0016 or P0017 fault codes.

Symptoms to notice

• Long cranking or hard starting
• Rough running or hesitation
• Check engine light
• Engine stalls while driving

What to check

At the viewing, ask for the recall completion record or dealer service history showing the recall was done, and give the VIN to a Mazda dealer to check whether the recall is still open. Start the engine from cold and listen for long cranking before it fires, and on the test drive feel for hesitation, surging or loss of power under steady throttle. Check the check engine light is not on. If a workshop inspection is possible: scan for fuel system and misfire codes and check fuel pressure.

Symptoms to notice

• Random or intermittent engine warning light that clears on restart
• Injector misfire or cylinder contribution fault codes that do not correlate to a single injector
• Boost pressure sensor codes P0237 or P0238 with no failed sensor found on test
• Rough running that cannot be replicated consistently for diagnostic purposes

What to check

1. 1.With the engine cool, trace the engine wiring harness from the injector rail connectors toward the turbocharger and exhaust manifold.
2. 2.Inspect the entire length of loom conduit and any exposed wiring for discoloured, cracked, or melted insulation.
3. 3.Look for areas where the loom contacts metal components, especially near the turbo body.
4. 4.Check that all OEM heat shielding around the turbocharger and exhaust is present and not displaced or missing.
5. 5.Inspect injector and sensor connector pin faces for corrosion or heat-induced oxidation.

Symptoms to notice

• Metallic rattle or clunk from the steering rack area when driving at low speed over rough or uneven surfaces
• Noise reproducible by rocking the steering wheel slightly at idle with the vehicle stationary
• Rattle is most pronounced during parking manoeuvres or when the wheel is near full lock at low speed
• No loss of steering assistance or control in early stages, but potential for increased steering play if tie rod ends are worn

What to check

Drive slowly over a speed hump or rough surface and listen for a metallic rattle or clunk localised to the steering rack area. With the engine running at idle, rock the steering wheel back and forth through a small range to replicate the noise without road input. Inspect rack mounting bushings for deterioration. If a workshop inspection is possible: On a hoist, check the inner tie rod ends for axial and lateral play by attempting to move them at the rack connection point.

Symptoms to notice

• Infotainment screen going black mid-drive with no response to touch or physical button inputs
• System boot loop on startup where the Mazda logo appears repeatedly without reaching the home screen
• Loss of backup camera, climate display, and audio control requiring a battery disconnect to reset
• Apple CarPlay or Android Auto connection dropping mid-journey and failing to reconnect without system restart

What to check

During the test drive, observe the infotainment screen for delayed boot, intermittent freezing, or unresponsive touch inputs. Attempt to pair a Bluetooth device and navigate through multiple menus simultaneously. Check that the system has the latest CMU firmware by inspecting the software version in Settings — earlier firmware versions are significantly more prone to lockup.

Symptoms to notice

• Significantly uneven brake pad wear with the inner pad worn to metal while the outer pad retains material, or vice versa
• Brake drag causing the vehicle to pull to one side under moderate braking
• Excessive brake dust accumulation on one wheel compared to the opposite side
• Burning smell from a wheel after normal driving, indicating continuous rotor contact and heat build-up

What to check

1. 1.Inspect rubber boots for splits, tears, or missing sections.
2. 2.Compare inner and outer brake pad thickness on each corner — a difference of more than 3 mm indicates a sticky caliper.
3. 3.Check disc surface for uneven wear grooves or blueing from heat on the side corresponding to the stuck pin.
4. 4.If a workshop inspection is possible: Remove each caliper and extract the guide pins; they must slide smoothly by hand throughout their full travel.

Symptoms to notice

• Surface rust visible at rear subframe mounting area on underbody inspection
• Bubbling or blistering of factory underseal around rear cross member flanges
• Rear suspension clunk or knock over rough surfaces
• Rear wheel alignment outside specification without accident history
• Visible active rust pitting at subframe bracket weld points

What to check

Watch for: Surface rust visible at rear subframe mounting area on underbody inspection. If a workshop inspection is possible: Place vehicle on a hoist and inspect the rear subframe mounting brackets and cross member welds with a torch and screwdriver; probe any blistered underseal to check for underlying metal loss; check inner faces of mounting flanges for rust scaling; confirm subframe bolts can be torqued to specification without thread strip — severe corrosion causes thread pull-out; verify rear wheel alignment is within spec.

Symptoms to notice

• Visible orange surface rust and paint delamination on the lower and inner faces of the front subframe visible from beneath the vehicle
• Scaling or flaking paint on the subframe cradle rails when inspected with a torch on a hoist
• Corrosion-related difficulty removing lower control arm bolts or engine mount hardware during servicing
• Roadworthy inspection advisory or failure note citing underbody corrosion in the front suspension area

What to check

Focus on the inboard faces of the subframe rails and the area around the front lower control arm mounting points. Probe any suspect areas with a blunt instrument — soft metal indicates advanced corrosion. Any roadworthy and inspection history showing a corrosion advisory on underside should be treated seriously. If a workshop inspection is possible: With the vehicle on a hoist, inspect the forward and lower faces of the front subframe cradle for orange surface rust, paint delamination, or scaling.

Symptoms to notice

• Rear-end wander or instability when driving at motorway speeds
• Uneven or diagonal wear pattern across the rear tyre tread
• Clunking or thudding from the rear axle area when driving over rough or unsealed roads
• Rear wheel alignment repeatedly going out of specification between services

What to check

1. 1.Inspect for oil contamination on bush surfaces, which rapidly degrades rubber compound.
2. 2.Measure rear wheel camber and toe against Mazda specifications — values outside tolerance often indicate collapsed bushes even when the damage is not yet visible.
3. 3.If a workshop inspection is possible: With the vehicle on a hoist, use a pry bar to lever each rear suspension arm and check for excessive rubber bush deflection or visible cracking.

Symptoms to notice

• Rear-end instability or wander at motorway speeds, requiring constant small steering corrections
• Audible clunking from the rear suspension when traversing speed humps or sharp road imperfections
• Rear wheel alignment persistently out of specification, particularly toe, despite recent alignment adjustment
• Increased tyre wear on the rear axle, often showing uneven edge wear

What to check

Then check at 6 and 12 o'clock for fore-aft play. Visually inspect all visible rubber bushings on the trailing arms and lateral links for cracking, splitting, or rubber extruding from the metal sleeve. A rear wheel alignment report showing toe values outside specification is a reliable indicator of bush collapse. If a workshop inspection is possible: On a hoist, grasp each rear wheel at 9 and 3 o'clock positions and push and pull laterally to check for play.

Symptoms to notice

• Amber EPB warning light illuminated on the instrument cluster, sometimes accompanied by an audible warning chime
• Electric parking brake failing to apply or release on demand, or applying unevenly between left and right rear
• Grinding or clicking noise from one rear corner when the EPB button is pressed
• Vehicle management system preventing gearshift from Park due to EPB fault detection

What to check

Check the EPB warning light status — an amber EPB light on the dashboard indicates a stored fault code. Physically apply and release the EPB multiple times and listen for smooth motor operation — grinding, clicking, or no response from one rear corner indicates actuator failure. Inspect both rear caliper-mounted actuators for corrosion or damage. If a workshop inspection is possible: With an OBD-II scanner capable of reading brake system modules, check for EPB actuator fault codes.

Symptoms to notice

• Harsh grinding or tearing sound from the rear during the first application of brakes after the vehicle has been parked overnight
• Vehicle pulling noticeably to one side under moderate braking, indicating unequal rear brake application
• Visible deep scoring or gouging on rear disc faces visible through the wheel spokes
• Rapid rear pad consumption compared to front pads over the same service interval

What to check

1. 1.Inspect rear disc faces for deep circumferential scoring, uneven wear lip, or patches of pad material bonded to the disc surface.
2. 2.Check rear caliper slide pins for free movement — seized pins cause uneven pad contact and accelerate the bonding problem.
3. 3.Compare pad thickness left vs right on each axle for uneven wear indicating a sticking caliper or seized pad.

Symptoms to notice

• Single clunk or knock from the front suspension when traversing bumps, speed humps, or rough surfaces
• Vague or imprecise steering feel with the vehicle wandering slightly under straight-line driving
• Uneven tyre wear on the front axle, typically feathering on one side of the tread
• Subtle vibration felt through the steering wheel over broken road surfaces

What to check

Visually inspect the ball joint dust boot for cracking, tearing, or grease expulsion. Drive the vehicle over a speed bump at low speed and listen for a single clunk from either front corner. Check tyre wear for feathering on the inner or outer edge. If a workshop inspection is possible: With the vehicle on a hoist, grasp the front wheel at the 6 and 12 o'clock positions and rock it vertically — any detectable play indicates ball joint wear.

Symptoms to notice

• Low humming or growling noise from the front that increases with vehicle speed
• Noise pitch changes or worsens when cornering in one direction as load transfers to the opposite bearing
• Vibration felt through the steering wheel at highway speeds
• Roughness or grinding felt when spinning the wheel by hand on a hoist

What to check

Grip the wheel at 3 and 9 o'clock and check for any lateral play. During the test drive at highway speed, listen for a speed-proportional hum from the front that changes pitch when weaving gently left and right — a bearing failing on one side will load and unload with each direction change. If a workshop inspection is possible: On a hoist, spin each front wheel by hand and feel for roughness, catching, or grinding.

Symptoms to notice

• Vehicle pulling to one side under braking, consistently toward the side with the seized caliper
• Brake pads wearing significantly faster on one side of an axle compared to the other
• Burning smell or heat felt from one wheel after normal driving
• Increased stopping distances and pedal feel changes as pad friction material glazes from constant contact

What to check

1. 1.Inspect brake pad thickness at all four corners — if one side of an axle is significantly thinner than the other, caliper seizure is the primary suspect.
2. 2.Check that rotors are not scored, blued from heat, or have a pronounced wear lip on the unswept inner edge.
3. 3.Check all four rubber guide pin boots for cracking or missing boots that have allowed water in.
4. 4.If a workshop inspection is possible: On a hoist, manually attempt to slide the caliper on its guide pins: a seized pin will prevent movement.

Symptoms to notice

• Rust on the metal ends of the tailgate struts
• Tailgate will not stay up

What to check

1. 1.Ask for the tailgate strut recall paperwork and check the VIN with a Mazda dealer.
2. 2.Open the tailgate and look at both gas struts: rust, swelling or splits on the metal end caps are a warning sign, and the tailgate should stay up on its own.
3. 3.If a workshop inspection is possible: the fitted struts can be checked against the recall replacement part numbers.

Symptoms to notice

• Knocking or rattling noise from the steering rack area when the front wheels pass over road imperfections
• A noticeable dead-zone or vague feeling when the steering wheel is near the straight-ahead position
• Noise intensity increasing in cold ambient temperatures due to reduced lubricant viscosity inside the rack
• Steering wheel vibration or shimmy transmitted back from the rack under braking

What to check

1. 1.With the engine running and wheels pointing straight ahead, firmly push and pull the steering wheel sideways while a second person observes the rack for movement at the mounting bushes and at the rack bar itself.
2. 2.Rock the steering wheel slightly at centre to feel for dead-spot play.
3. 3.Check rack mounting bush condition.
4. 4.Verify for any relevant Mazda TSB updates on yoke adjuster specification.

Symptoms to notice

• Vague or wandering steering feel at motorway speed, requiring constant small corrections
• Clunking or knocking from the rear suspension over road bumps or dips
• Uneven rear tyre wear — feathering on the inner or outer edge
• Vehicle pulling to one side under braking
• Visible cracking, splitting, or deformation of bush outer rubber on inspection

What to check

During the test drive, note any vagueness or floating sensation when changing lanes at motorway speed. Inspect rear tyre wear for feathering on the inner or outer edge, which indicates dynamic toe change from worn bushes. If a workshop inspection is possible: Place the vehicle on a hoist and use a pry bar to check for excess deflection at each trailing arm bush mount and rear subframe mounting point.

Symptoms to notice

• Oil staining or pooling directly beneath the rear differential housing, particularly around the front propshaft flange
• Burning oil smell from the rear of the vehicle after highway driving as oil contacts hot brake components
• Rear brake fade, sponginess, or reduced braking performance from oil-contaminated pads
• Differential whine or gear noise under load as oil level drops from ongoing seal leak

What to check

1. 1.Check the area immediately behind the rear differential for oil residue on the floor or on the propshaft.
2. 2.Inspect rear brake discs and pads for oil contamination — glazed or discoloured pads indicate possible seal leak history.
3. 3.If a workshop inspection is possible: With the vehicle on a hoist, inspect the front face of the rear differential housing where the propshaft flange connects, looking for oil weeping, staining, or pooling around the input shaft seal.