Code
P02DB
Generic
P — Powertrain
Cylinder 8 Fuel Injector A Offset Learning At Max Limit
Views:
UK: 22
EN: 29
RU: 20
AI status
Completed
Completed
100%
Causes
- Sticking, clogged, or leaking fuel injector (cylinder 8)
- Open, shorted, or intermittent injector wiring or poor connector/ground
- Low or fluctuating fuel rail pressure or faulty fuel pressure regulator
- Cylinder mechanical problems (low compression, valve issues, head gasket leak)
- PCM/ECM software/learning table limit reached or memory fault
- Contaminated fuel or internal injector electrical/driver failure
Symptoms
- Check Engine Light (MIL) illuminated
- Rough idle or vibration, often attributable to cylinder 8
- Reduced engine power, hesitation or poor throttle response
- Increased fuel consumption
- Occasional or persistent misfire code(s) for cylinder 8
What to check
- Read freeze frame and stored data; note other related DTCs (misfire, fuel pressure, cam/crank)
- Visual inspection of injector harness, connector, pins and grounds for corrosion or damage
- Measure injector coil resistance and compare to spec
- Use a noid light or scope to verify injector pulse and driver signal at cylinder 8
- Monitor live data: commanded pulse width, actual pulse, learned offset value, fuel rail pressure and battery voltage
- Check fuel rail pressure, regulator operation and fuel supply (pump, filter)
Signal parameters
- Injector commanded pulse width (ms)
- Injector learned offset or adaptive value (units depend on manufacturer)
- Injector pulse presence and duty cycle
- Fuel rail pressure (psi/bar)
- Short-term and long-term fuel trims
- Cylinder contribution/trim or misfire counters
Diagnostic algorithm
- Retrieve DTC, freeze frame and note any other codes. Do not assume this code alone is root cause.
- Perform a visual inspection of wiring, connectors and grounds for cylinder 8 injector. Repair obvious damage.
- Verify battery voltage and charging system; low voltage can prevent proper learning.
- With a scan tool, monitor commanded injector pulse and the learned offset value while engine is running or during a relearn procedure.
- Measure injector coil resistance and compare to spec. Use a scope/noid light to confirm injector driver pulses at the connector.
- Check fuel rail pressure under idle and load; confirm regulator and pump operation and fuel filter condition.
- Perform a compression or leak-down test on cylinder 8 to rule out mechanical causes affecting fuel correction.
- If electrical tests are normal, swap the suspect injector with another cylinder and clear codes. If the code follows the injector, replace the injector.
- If the code remains on cylinder 8 after swapping, focus on wiring, connector, PCM driver circuit or mechanical causes.
- After repair or replacement, clear codes and perform manufacturer-specified injector offset relearn using a scan tool or run the required drive cycle to allow the PCM to relearn. Verify the offset is within normal range and repeat tests if necessary.
- If injector and vehicle systems test OK but learning still maxes out, consider PCM software update or replacement as a last resort.
Likely causes
- Faulty injector on cylinder 8 (most likely)
- Wiring harness connector or pin corrosion/loose connection to injector
- Inadequate or unstable fuel pressure
- Cylinder 8 mechanical condition (compression/leakdown)
- PCM cannot learn due to an unrelated engine condition (misfire, timing, low voltage)
Fault status
Status
Cylinder 8 Fuel Injector A offset learning reached maximum limit — PCM cannot further compensate. Check injector, wiring, fuel supply and cylinder mechanical condition.
Repair difficulty: Medium
Diagnostic time: 1-4 hours
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