P0278: Cylinder 6 is not contributing equally to engine power
Cylinder 6 contribution/balance fault
Severity: Severity not verified — if the car runs badly, have it inspected
No source here rates the urgency of a cylinder balance fault, so the class is not verified. TroubleCodes.net says there is often no noticeable drivability issue at first.
It gets more serious if:
- Inspect soon: Inspect soon if the engine misfires or runs rough. TroubleCodes.net lists these as symptoms in severe cases.
P0278 in short
P0278 means the engine computer found that cylinder 6 is not contributing as much power as the others. Dirty or faulty injectors are the most common cause, and worn rings, burnt valves or a head gasket leak are the mechanical ones. Get it checked if the engine runs rough.
The computer watches crankshaft speed during each cylinder's power stroke. If one cylinder pushes less than the rest, it logs a balance fault for that cylinder.
TroubleCodes.net names dirty or faulty fuel injectors as the most common cause, mechanical wear such as worn piston rings, burnt valves or a head gasket leak, and an injector replaced without the learning procedure being done.
Because the code names cylinder 6, the check compares that cylinder's injector with its neighbours, then moves to compression tests.
Most likely causes
These are general causes for this code across vehicles. None is specific to one make or model.
Cause 1: Dirty or faulty injector on cylinder 6
Common general cause- Why it ranks here
- TroubleCodes.net lists dirty or faulty injectors as the most common cause.
- What would change this
- Rises if the injector waveform or sound differs from its neighbours. Falls if it matches them.
Cause 2: Injector replaced without the learning procedure
Possible — needs testing- Why it ranks here
- The reference page lists this as a cause after an injector replacement.
- What would change this
- Rises if an injector was recently replaced. Falls if no injector work has been done.
Cause 3: Engine wear: piston rings, valves or head gasket
Possible — needs testing- Why it ranks here
- Listed as the mechanical causes; confirmed by compression and leakdown tests.
- What would change this
- Rises if compression or leakdown on this cylinder is low. Falls if the readings are even.
What to test first
Start at step 1. Each result tells you what it means and where to go next.
Step 1: With the engine off, check the cylinder 6 injector connector for corrosion or water damage.
IfCorrosion or water is found
It meansRepair the connector and recheck.
IfThe connector is clean
It meansCompare the injector with its neighbours.
Step 2: Compare the injector's waveform and sound with the neighbouring cylinders.
Warning:The engine is running with belts and fans near the injectors. A shop should do this.
IfThe injector differs from the others
It meansThe injector is the likely cause.
IfIt matches the others
It meansCheck engine mechanical condition.
Step 3: Have compression and leakdown tests done on the cylinder.
Warning:The engine must be disabled from firing and cranked with spark plugs removed; fuel and ignition must be disabled correctly.
IfLow compression or high leakdown
It meansMechanical wear.
IfReadings are even
It meansAsk whether an injector learning procedure is needed.
Symptoms
- Check engine light
- Reduced fuel economy and performance
- Rough idle or misfire in severe cases Gets more serious: stop and have it checked.
Compare with: Car shaking with the check engine light on
How to fix
Step 1: With the engine off and cool, check that the injector connector for that cylinder is fully seated and free of corrosion.
Parts and cost context
- Fuel injector:Test the injector and wiring before replacing; labor varies, get a quote.
Labor varies by vehicle and shop; get a quote before you approve a repair.
Compare used part prices on PartPriceGuideOn your vehicle
VolkswagenYour car
2009–2010 · Touareg
Supported by vehicle dataVolkswagen bulletin TB011418 covers update programming for cylinder contribution faults P0263, P0266, P0269, P0272, P0275 and/or P0278. Whether it is still current is not verified.
TB011418Status unverified
Volkswagen bulletin: update programming for cylinder contribution faults P0263 through P0278
2009–2010touareg · issued · NHTSA 10241321
Volkswagen bulletin TB011418 for the 2009-2010 Touareg. The summary says update programming applies to cylinder contribution faults P0263, P0266, P0269, P0272, P0275 and/or P0278 stored in ECM fault memory. Only the NHTSA summary was read, not the full bulletin; the summary does not give the repair.
We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.
Related codes
No curated relationships for P0278 yet.
Sources and review
- P0278 trouble code
- TB011418: Volkswagen bulletin: update programming for cylinder contribution faults P0263 through P0278
- On-Board Diagnostic Trouble Codes (generic code title list)
- Last reviewed
- Written by
- Saurabh K.
- Editorial review
- Pending
- Technician review
- Technician review pending
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