Code
P02CF
Generic
P — Powertrain
Cylinder 2 Fuel Injector A Offset Learning At Max Limit
Views:
UK: 20
EN: 34
RU: 30
AI status
Completed
Completed
100%
Causes
- Injector hydraulic performance out of spec (clogged, leaking, worn)
- Injector driver circuit electrical fault (open, short, high resistance)
- Poor connector/ground or damaged wiring to injector
- Incorrect injector installed or mismatched injector characteristics
- Fuel pressure or delivery problems (low rail pressure, regulator fault)
- Low cylinder compression or mechanical engine issue
Symptoms
- Illuminated MIL (Check Engine Light)
- Rough idle or vibration at idle
- Intermittent or consistent misfire on cylinder 2
- Reduced fuel economy
- Reduced engine power or hesitation under load
- Difficulty passing emissions or inspection
What to check
- Read freeze frame and live data: injector offset/correction value for cylinder 2, injector pulse width, fuel trims, misfire counters
- Scan for additional codes (e.g., misfire or injector circuit codes)
- Visual inspection of injector connector, pins, wiring harness and ground
- Measure injector resistance with multimeter and compare to spec
- Back-probe injector signal while cranking/running to verify pulse and voltage
- Measure fuel rail pressure and regulator operation
Signal parameters
- Injector pulse width (ms) — expected range varies with load and RPM
- Injector learned offset / adaptation value (percent or ECU-specific units)
- Short-term and long-term fuel trim (%)
- Misfire counter for cylinder 2 (events/min or counts)
- Fuel rail pressure (kPa or psi)
- Battery voltage (V) during cranking and idle
Diagnostic algorithm
- Record codes and freeze-frame data. Clear codes and attempt to re-run to reproduce the condition.
- Check for related DTCs (misfire, injector circuit codes, fuel pressure) to prioritize repairs.
- Visually inspect wiring, connectors and grounds for corrosion, damage or looseness at cylinder 2 injector.
- Measure injector resistance and compare to spec. If out of range, replace injector.
- Back-probe injector while engine is running (or cranking) to verify injector drive voltage and pulse. Look for intermittent or weak drive.
- Measure fuel rail pressure under static and dynamic conditions; repair fuel supply issues if pressure is low or unstable.
- Swap the suspect injector with another cylinder (if practical) and clear codes. If the learned offset fault follows the injector, replace the injector.
- Perform compression or leak-down test on cylinder 2 to rule out mechanical causes affecting combustion and injector learning.
- If wiring and injector bench tests are good but problem persists, check ECM software updates and consider ECM/driver circuit diagnosis by a specialist.
- After repair or replacement, reset learned values, perform a relearn procedure if required, road-test and confirm code does not return.
Likely causes
- Clogged or partially clogged injector on cylinder 2
- High resistance or intermittent connection at injector connector
- Injector driver transistor within ECM marginal or failing
- Fuel rail pressure low or unstable
- Wrong injector flow rate fitted during service
- Cylinder 2 compression low (valve, piston ring or head gasket issue)
Fault status
Status
The ECM reports that the learned offset for Cylinder 2 Fuel Injector A is at the maximum allowable limit; the controller cannot further compensate for the injector's deviation. This condition typically triggers MIL and suggests a faulty injector, wiring, fuel delivery, or mechanical issue affecting that cylinder.
Repair difficulty: Medium
Diagnostic time: 1-4 hours
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