Clogged or partially restricted fuel injector on cylinder 6; Internal injector wear or electrical solenoid failure causing incorrect flow; Wiring harness damage or poor connection at the cylinder 6 injector; Fuel contamination or low fuel pressure affecting injector performance; Faulty engine control module adaptive learning memory or software; Mechanical engine issue such as low compression on cylinder 6 altering combustion

DTC codes / P2Cxx · Hybrid propulsion / P2C5D

P2C5DCylinder 6 Fuel Injector B Offset Learning At Max Limit

Q: What does code P2C5D mean?

Cylinder 6 Fuel Injector B Offset Learning At Max Limit. P2C5D indicates that the engine control module has learned a fuel injector offset correction for cylinder 6 that has reached its maximum allowed limit, meaning the injector is flowing outside the expected range and the computer can no longer compensate. The ECM monitors injector performance during closed-loop operation and stores this code when the adaptive learning value for that injector saturates at the upper threshold.

P2C5D indicates that the engine control module has learned a fuel injector offset correction for cylinder 6 that has reached its maximum allowed limit, meaning the injector is flowing outside the expected range and the computer can no longer compensate. The ECM monitors injector performance during closed-loop operation and stores this code when the adaptive learning value for that injector saturates at the upper threshold.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyProfessional

AreaHybrid propulsion

Symptoms you may notice

Illuminated check engine light, often with no other noticeable symptoms
Rough idle or misfire that may be intermittent, especially when the engine is cold
Slight loss of power or hesitation during acceleration
Decreased fuel economy due to improper fuel delivery
Possible fuel odor or black smoke from the exhaust if the injector is over-fueling

Common causes, most likely first

Clogged or partially restricted fuel injector on cylinder 6
Internal injector wear or electrical solenoid failure causing incorrect flow
Wiring harness damage or poor connection at the cylinder 6 injector
Fuel contamination or low fuel pressure affecting injector performance
Faulty engine control module adaptive learning memory or software
Mechanical engine issue such as low compression on cylinder 6 altering combustion

How to diagnose and fix it

Connect a scan tool and verify P2C5D is current, then check for any related misfire or fuel trim codes
Inspect the cylinder 6 injector connector and wiring for corrosion, chafing, or loose pins
Measure fuel pressure and compare to specification to rule out a supply problem
Perform an injector balance test or cylinder contribution test to confirm the injector is the faulty component
Remove and flow-test the cylinder 6 injector, or swap it with a known-good injector to see if the code follows
Replace the faulty fuel injector and clear adaptive learning values with the scan tool
Road-test the vehicle to allow the ECM to relearn injector offsets and confirm the code does not return

When the injector is not the real culprit

A saturated offset learning value can be caused by a vacuum leak or exhaust leak near cylinder 6 that skews the oxygen sensor reading and forces the ECM to max out injector correction.
Technicians often replace the injector only to find the code returns because the fuel injector driver circuit inside the ECM has degraded, especially on higher-mileage vehicles.
Low compression or a worn camshaft lobe on cylinder 6 can mimic an injector fault by changing the engine's breathing, so a compression test should precede injector replacement.
The code may set intermittently and clear itself after a few drive cycles if the injector is only marginally restricted, leading owners to ignore a developing problem.
After replacing the injector, failing to reset the adaptive learning values will leave the ECM using the old maxed-out offset, and the code will reappear immediately.

Can I keep driving with P2C5D?

You can usually continue driving short distances, but avoid heavy acceleration or towing until the fault is repaired because prolonged driving with a maxed-out injector offset can lead to catalytic converter damage or engine misfire. Have the vehicle diagnosed promptly to prevent secondary damage.

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.