Clogged, restricted, or dirty fuel injector on cylinder 7; Failed or leaking fuel injector on cylinder 7; Wiring fault or poor electrical connection at the cylinder 7 injector harness; Low fuel pressure or a restricted fuel supply affecting that injector; Internal engine mechanical issue such as low compression on cylinder 7; Contaminated fuel or fuel system deposits affecting injector performance; Engine control module software calibration issue or faulty injector driver circuit

DTC codes / P02xx · Fuel and air metering (injector circuits) / P02D9

P02D9Cylinder 7 Fuel Injector A Offset Learning At Max Limit

Q: What does code P02D9 mean?

Cylinder 7 Fuel Injector A Offset Learning At Max Limit. P02D9 indicates that the engine control module has learned a fuel injector offset correction for cylinder 7 that has reached its maximum allowable limit, meaning the injector is flowing outside the range the computer can compensate for. The computer detects this when the short-term fuel trim or injector pulse-width adaptation for that specific cylinder can no longer bring the air-fuel ratio back to target.

P02D9 indicates that the engine control module has learned a fuel injector offset correction for cylinder 7 that has reached its maximum allowable limit, meaning the injector is flowing outside the range the computer can compensate for. The computer detects this when the short-term fuel trim or injector pulse-width adaptation for that specific cylinder can no longer bring the air-fuel ratio back to target.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaFuel and air metering (injector circuits)

Symptoms you may notice

Illuminated check engine light, often with no other noticeable symptoms
Rough idle or a noticeable vibration that may be worse when the engine is cold
Slight misfire or hesitation during acceleration, particularly under light load
Decreased fuel economy as the computer struggles to correct the imbalance
A faint fuel odor from the exhaust if the injector is over-fueling
In rare cases, a flashing check engine light if the misfire becomes severe enough to damage the catalytic converter

Common causes, most likely first

Clogged, restricted, or dirty fuel injector on cylinder 7
Failed or leaking fuel injector on cylinder 7
Wiring fault or poor electrical connection at the cylinder 7 injector harness
Low fuel pressure or a restricted fuel supply affecting that injector
Internal engine mechanical issue such as low compression on cylinder 7
Contaminated fuel or fuel system deposits affecting injector performance
Engine control module software calibration issue or faulty injector driver circuit

How to diagnose and fix it

Perform a visual inspection of the cylinder 7 injector connector and harness for corrosion, chafing, or loose pins
Check fuel pressure and fuel quality to rule out a supply-side restriction or contamination
Run a cylinder contribution or injector balance test with a scan tool to compare cylinder 7 against the others
Perform a compression test and, if needed, a cylinder leak-down test on cylinder 7 to rule out mechanical faults
Remove and flow-test the cylinder 7 injector, or swap it with a known-good injector from another cylinder to see if the code follows
Clean or replace the cylinder 7 fuel injector if it fails flow or resistance testing
Clear the adaptive learning values and re-learn the injector offsets, then verify the code does not return after a road test

What the offset learning limit really means

A maxed-out offset learning value does not automatically condemn the injector; a weak spark plug, coil, or vacuum leak on that cylinder can force the computer to overcompensate the injector and set this code.
Many technicians replace the injector without first checking compression on cylinder 7, and a mechanical fault such as a worn cam lobe or valve seat will set the same code again on the new part.
Fuel injector offset learning is sensitive to fuel pressure, so a failing fuel pump or a clogged fuel filter can cause this code on one cylinder even when the injector itself is healthy.
This code can appear after a battery replacement or ECU reflash because the learned values are cleared, and the computer must relearn offsets from scratch; a short drive cycle may resolve it without any repair.
A dirty mass airflow sensor or a small intake leak can skew the air-fuel mixture enough that the computer reaches the offset limit on a single cylinder, so always check fuel trims across all cylinders before condemning the injector.

Can I keep driving with P02D9?

You can usually drive the vehicle short distances at moderate speed, but avoid heavy acceleration or towing until the fault is diagnosed because a persistent rich or lean condition on cylinder 7 can damage the catalytic converter over time. If the check engine light begins flashing, stop driving and have the vehicle towed.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.