Clogged, restricted, or failing fuel injector on cylinder 2; Intake manifold vacuum leak near cylinder 2 runner; Faulty or contaminated fuel injector connector or wiring harness; Low fuel pressure or volume from a weak fuel pump or restricted filter; Mechanical issue such as low compression or valve sealing on cylinder 2; ECM software calibration issue or internal driver fault (less common)

DTC codes / P2Cxx · Hybrid propulsion / P2C55

P2C55Cylinder 2 Fuel Injector B Offset Learning At Max Limit

Q: What does code P2C55 mean?

Cylinder 2 Fuel Injector B Offset Learning At Max Limit. P2C55 indicates that the engine control module (ECM) has learned a fuel injector offset correction for cylinder 2 that has reached its maximum allowable limit, meaning the injector is flowing outside the range the ECM can compensate for. The ECM detects this when the short-term fuel trim or injector pulse-width adaptation for that cylinder cannot bring the air-fuel ratio back to target.

P2C55 indicates that the engine control module (ECM) has learned a fuel injector offset correction for cylinder 2 that has reached its maximum allowable limit, meaning the injector is flowing outside the range the ECM can compensate for. The ECM detects this when the short-term fuel trim or injector pulse-width adaptation for that cylinder cannot bring the air-fuel ratio back to target.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaHybrid propulsion

Symptoms you may notice

Illuminated check engine light, often with no other noticeable symptoms
Rough idle or misfire sensation, especially when the engine is cold
Slight hesitation or stumble during acceleration
Decreased fuel economy over time
Elevated hydrocarbon emissions or a fuel smell from the exhaust
In rare cases, a noticeable loss of power under load

Common causes, most likely first

Clogged, restricted, or failing fuel injector on cylinder 2
Intake manifold vacuum leak near cylinder 2 runner
Faulty or contaminated fuel injector connector or wiring harness
Low fuel pressure or volume from a weak fuel pump or restricted filter
Mechanical issue such as low compression or valve sealing on cylinder 2
ECM software calibration issue or internal driver fault (less common)

How to diagnose and fix it

Connect a scan tool and record freeze-frame data and fuel trim values for cylinder 2 to confirm the offset is at its limit.
Perform a visual inspection of the cylinder 2 injector connector, wiring, and intake seals for damage or vacuum leaks.
Measure fuel pressure and volume at the rail to rule out a supply problem before condemning the injector.
Run a cylinder contribution or power-balance test to compare cylinder 2 against the others.
Swap the cylinder 2 injector with a known-good injector from another cylinder and recheck the offset learning value.
If the offset follows the injector, replace the faulty injector and clear the adaptive learning; if it stays with the cylinder, perform a compression and leak-down test.
After repair, drive the vehicle through the manufacturer's relearn procedure and verify fuel trims return to normal.

What the offset limit really tells you

A maxed-out offset does not automatically mean the injector is bad; a vacuum leak or low fuel pressure can force the ECM to max out correction on a perfectly healthy injector.
Many technicians replace the injector without checking fuel pressure first, only to find the code returns because the pump was weak all along.
The offset learning value is stored in adaptive memory, so clearing codes without fixing the root cause will let the code return after a few drive cycles.
A mechanical fault such as a burnt valve or worn cam lobe on cylinder 2 can mimic an injector offset problem because the ECM tries to compensate for poor airflow.
On some vehicles, this code sets only after a specific number of cold-start cycles, so a test drive alone may not immediately reproduce it.

Can I keep driving with P2C55?

You can usually continue driving short distances at moderate speeds, but avoid heavy acceleration or towing until the fault is diagnosed. Prolonged driving with a maxed-out injector offset can damage the catalytic converter and worsen fuel dilution in the oil.

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.