Powertrain, generic · Fuel and air metering (injector circuit)

P02C6 Cylinder 12 - Fuel Trim at Max Limit

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

These codes belong to an individual-cylinder fuel correction: a diesel's cylinder balance control measures each cylinder's crankshaft acceleration and adjusts its injection quantity; on petrol engines a cylinder-selective mixture control does the same. CARB requires the system to report when such a correction has used up its range or one cylinder causes an imbalance. P02C6 means the correction for cylinder 12 is at its upper limit: the module keeps giving this cylinder more fuel and still cannot even it out – a sign that the cylinder receives too little fuel or builds too little pressure. Cylinder 12 only exists on engines with twelve or more cylinders. GM and Ford use other codes for this (P0263 ff, P219A ff); no manufacturer document describing this code with thresholds was found, so the description follows CARB and published patents.

Likely causes

Injector of cylinder 12 coked or partly clogged
Compression loss in this cylinder (valve, rings, leak at injector or glow plug)
Injector circuit high-resistance or connector
Petrol: false air at this cylinder's intake (manifold gasket)
Injector correction code missing or wrong after replacement

Symptoms

  • Check engine light on
  • Rough idle, vibration
  • Lack of power, possibly misfire

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€100–900
Time1–4 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

fuel injector cylinder 12crankshaft position sensorengine control module

Related codes

P02C7P02C8P02C9P0171P0296P232E

References: law.cornell.edu, patents.google.com, patents.google.com.