A clogged, dirty, or partially restricted fuel injector on cylinder 4; A failing fuel injector solenoid or internal wear on the cylinder 4 injector; Carbon buildup on the intake valve or in the combustion chamber of cylinder 4; A small intake or exhaust leak near cylinder 4 that skews the air-fuel reading; Low fuel pressure or a weak fuel pump that affects one injector more than others; A wiring fault or poor connector contact at the cylinder 4 injector; An engine mechanical issue such as low compression or a worn cam lobe on cylinder 4

DTC codes / P2Cxx · Hybrid propulsion / P2C59

P2C59Cylinder 4 Fuel Injector B Offset Learning At Max Limit

Q: What does code P2C59 mean?

Cylinder 4 Fuel Injector B Offset Learning At Max Limit. This code means the engine computer has reached the maximum allowed adjustment for the fuel injector offset on cylinder 4, which is the small correction it applies to that injector's opening time to keep fueling balanced. The computer detected that its learned offset value for injector B on cylinder 4 has hit the calibration limit, so it can no longer compensate for the imbalance it is seeing.

This code means the engine computer has reached the maximum allowed adjustment for the fuel injector offset on cylinder 4, which is the small correction it applies to that injector's opening time to keep fueling balanced. The computer detected that its learned offset value for injector B on cylinder 4 has hit the calibration limit, so it can no longer compensate for the imbalance it is seeing.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyProfessional

AreaHybrid propulsion

Symptoms you may notice

Illuminated check engine light, often with no other symptoms besides the warning light
A noticeable rough idle or shaking that is worse when the engine is cold
Slight misfire or hesitation under light acceleration
Poor fuel economy compared with normal driving
A faint fuel smell or occasional puff of black smoke from the exhaust
In some cases, reduced engine power or a limp-home mode if the imbalance worsens

Common causes, most likely first

A clogged, dirty, or partially restricted fuel injector on cylinder 4
A failing fuel injector solenoid or internal wear on the cylinder 4 injector
Carbon buildup on the intake valve or in the combustion chamber of cylinder 4
A small intake or exhaust leak near cylinder 4 that skews the air-fuel reading
Low fuel pressure or a weak fuel pump that affects one injector more than others
A wiring fault or poor connector contact at the cylinder 4 injector
An engine mechanical issue such as low compression or a worn cam lobe on cylinder 4

How to diagnose and fix it

Scan all modules and record freeze-frame data for P2C59, then check for related misfire or fuel trim codes
Inspect the cylinder 4 injector connector and wiring for corrosion, chafing, or loose pins
Measure fuel pressure and compare it with the manufacturer's specification
Run an injector balance test or cylinder contribution test to confirm the cylinder 4 injector is the weak one
Perform a compression test and, if needed, a cylinder leak-down test on cylinder 4
Clean or replace the cylinder 4 injector, then clear the adaptive learning and road-test to confirm the offset returns within limits
If the offset still maxes out, inspect the intake for leaks and check valve timing and camshaft condition

What the offset limit really tells you

A maxed-out injector offset does not automatically mean the injector is bad, because a vacuum leak or low fuel pressure can force the computer to its correction limit first.
Technicians often replace the cylinder 4 injector only to find the real fault is a carbon-fouled intake valve that was skewing the airflow reading for that cylinder.
The offset learning value is stored in the engine computer's adaptive memory, so clearing codes without fixing the root cause will let the code return after a few drive cycles.
A weak ignition coil or spark plug on cylinder 4 can mimic an injector imbalance because the computer sees the same rough-running signal and tries to correct fueling.
On engines with direct injection, a maxed offset can point to a worn high-pressure fuel pump or a leaking injector seal rather than the injector itself.

Can I keep driving with P2C59?

You can usually drive the vehicle short distances to a repair shop, but avoid heavy acceleration, towing, or long highway trips until the fault is diagnosed. Continued 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.