GWM Cannon: common faults & what to check

Which GWM Cannon are you looking at?

2 generation variants documented. Pick the shape you recognise: the faults, the servicing and the timeline below all narrow to it. Free, no account needed.

Diesel

2 variants documented

2020–now2020–nowGeneration2.0 turbo-dieselDieselDocumented issues5 knownSee faults & what to checkKickTyres illustration, not a photograph.

2020–now2020–nowGeneration2.4 turbo-dieselDieselDocumented issues3 knownSee faults & what to checkKickTyres illustration, not a photograph.

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.

Start your free check on this GWM Cannon

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.

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

• Serious issue

  Open the bonnet cold and look and sniff around the diesel fuel filter housing for wetness, staining or diesel smell.

  See why

  Fuel filter O-ring leak — fire risk (recall REC-006123)

  GWM recalled 2,872 Cannon utes built in 2023 because the wrong lubricant was applied to the diesel fuel filter O-ring at the factory, letting the seal degrade and diesel leak from the filter housing — a fire risk near an ignition source. The fix is a free O-ring replacement at a GWM dealer under Australian recall REC-006123 (a matching NZ campaign ran through GWM NZ dealers); recall rectification does not expire, but an unrepaired car is a genuine hazard. Any 2023-build Cannon should have dealer paperwork showing the recall was completed.

  What you would notice

  • Diesel smell around engine bay
  • Wet/oily film or drips around fuel filter housing
  • Fuel stains on driveway under engine
  • Recall letter received but never actioned

  Typically $150–$600 to put right.

• Costly issue

  On the test drive include a 10+ minute drive and watch for power flat spots or a hot acrid smell afterwards.

  See why

  DPF blocking and constant regeneration on urban-driven early Cannons

  Early (2020–2021) 2.0 turbo-diesel Cannons were notorious for near-constant DPF regeneration burns and a flat spot in acceleration, especially when driven mostly around town without regular open-road runs. GWM released an ECU update that largely fixed the constant regens and the dead spot, so an un-updated example may still show the old behaviour. A truly blocked DPF causes power loss, higher fuel use and, if ignored, turbo or engine damage; replacement DPFs are dealer-only parts in NZ.

  What you would notice

  • Frequent regeneration (hot exhaust smell, elevated idle, fans running after shutdown)
  • Rising fuel consumption
  • Loss of power / limp mode
  • DPF warning light
  • Diesel smoke on acceleration

  Typically $250–$4,000 to put right.

• Costly issue

  Scan for DPF backpressure and soot load fault codes.

  See why

  Diesel Particulate Filter Blockage on Short-Trip Use

  The GWM Cannon's GW4C20NT 2.0-litre diesel is fitted with a DPF that requires regular highway-speed driving to complete passive and active regeneration cycles. Owners using the Cannon predominantly on short urban runs or low-speed tracks without sustained highway driving experience DPF blockage, triggering a warning light and forcing a dealer-initiated forced regeneration or physical DPF removal and clean. The problem is compounded by owners switching the engine off mid-regeneration cycle.

  What you would notice

  • DPF warning light on dashboard
  • Reduced engine power or limp mode
  • Increased fuel consumption
  • Strong sulphur or burning smell from exhaust during forced regen

  Typically $400–$3,800 to put right.

• Costly issue

  Remove intake hose from turbo compressor outlet and inspect for oily film or visible shaft play by wiggling the compressor wheel.

  See why

  GW4C20 Turbo Bearing Failure & Oil Coking

  The GW4C20 2.0T turbocharger uses a ball-bearing centre cartridge fed by a pressurised oil feed line. Under sustained high-load driving followed by hot shutdown without idle cool-down, residual heat soak causes the thin oil film in the feed passages to carbonise (coke), restricting flow to the bearing. Progressive bearing wear then accelerates, typically presenting first as axial shaft play, then compressor-wheel contact with the housing. The oil drain passage at the base of the CHRA is particularly prone to partial blockage from coked deposits, which also forces oil past the compressor seal into the inlet tract.

  What you would notice

  • Blue-tinged exhaust smoke under boost or on overrun
  • Oily residue inside intake hose between turbo and intercooler
  • Whistling or whining noise that changes pitch with engine RPM
  • Noticeable power loss under hard acceleration
  • Oil consumption above 500ml per 5,000km

  Typically $3,500–$8,000 to put right.

• Costly issue

  Scan for SCR and AdBlue system fault codes.

  See why

  AdBlue Dosing Pump Failure

  The selective catalytic reduction system on the GW4C20NT diesel uses an AdBlue dosing pump to inject urea solution into the exhaust stream. Dosing pump failures presenting as a faulty actuator or blocked injector nozzle have been reported on higher-mileage Cannon units, triggering a DEF system fault code and eventually disabling engine starting after a set warning period if unresolved. The pump and nozzle assembly is not serviceable and replacement is required. Sourcing OEM parts through GWM AU dealers can involve extended lead times.

  What you would notice

  • AdBlue or DEF warning light on dashboard
  • Fault code relating to SCR dosing pump or injector
  • Countdown message indicating remaining starts before immobilisation
  • No visible AdBlue consumption despite pump running

  Typically $900–$2,200 to put right.

• Costly issue

  Inspect the rear differential casing and output shaft flanges for oil weeping or staining.

  See why

  Rear Differential Output Shaft Oil Seal Leak

  The rear differential pinion and output shaft oil seals on the GWM Cannon have been identified as a recurring leak point, particularly on vehicles operated in off-road conditions or subject to water crossings. The seals degrade prematurely under heat cycling and contamination ingress, allowing gear oil to weep from the differential casing. If undetected, continued operation with low differential oil risks bearing and gear surface damage requiring differential rebuild or replacement.

  What you would notice

  • Oil staining or wet patch beneath the rear differential
  • Gear oil smell from the rear axle area
  • Differential oil level below minimum on check
  • Whining or grinding from the rear diff under load if oil has been lost

  Typically $350–$1,200 to put right.

GWM Cannon service schedule

What falls due, and at what distance, for each generation of the GWM Cannon. 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.

What these repairs cost on other cars

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

• DPF Repair and Replacement Cost
• Turbo Repair and Replacement Cost

Buying guides that cover the GWM Cannon

• How Chinese brands took a quarter of the market in four years

Other GWM models