Powertrain, generic (extended)

P2C59 Cylinder 4 Fuel Injector B Offset Learning At Max Limit

Check engine lightOn

EmissionsRelevant

Drive cycleRequired

Limp modeNo

P2C59 tells that injector B of cylinder 4 has reached the maximum learned offset, so its delivery falls short even with the longest allowed correction. Volvo's Technical Journal 36016 includes it among four codes, one per cylinder from 1 to 4 and all at the Max limit, on 2022 model-year cars; the first step there is software, not parts. Outside such a bulletin, a swap test helps: move injector B of cylinder 4 to another cylinder, reset the adaptations and let the learn run again. If the Max code follows the injector, the valve is at fault; if it stays with cylinder 4, wiring, connector or the intake side of that cylinder are next. CARB 1968.2 (e)(6.2.2) treats an adaptation out of authority as a malfunction.

Likely causes

Engine software (Volvo TJ 36016: update, then reset injector adaptations in VIDA)

Varnish or deposits in injector B of cylinder 4, slow opening

Corroded or loose connector, chafed wire or voltage drop at this injector

Air leak at the intake runner of cylinder 4 (only where the learn uses exhaust oxygen)

Symptoms

Check engine light
Usually no change in how the car drives
Possibly uneven idle or lean misfire on cylinder 4

Repair estimate

DifficultyMediumWorkshop job

Parts and labour€0–700

Time0.3–3 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

fuel injector b cyl 4ecm

References: law.cornell.edu, static.nhtsa.gov, static.nhtsa.gov, patents.google.com.