Powertrain, generic · Fuel and air metering (injector circuit)

P02DC Cylinder 9 Fuel Injector A Offset Learning At Min Limit

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

The engine module learns a small-quantity correction for each injector: on overrun it gives one injector a tiny test injection (GM about 1.5 mm³), measures the resulting crankshaft acceleration and corrects the injector's activation time per rail pressure step. P02DC means the learned correction for cylinder 9 has reached its lower limit at at least one pressure step: the injector needs much less activation time than nominal – it delivers too much at small quantities or opens early. Cylinder 9 exists only on ten-cylinder engines; no manufacturer using this code was found, so the description follows CARB and the documented codes for cylinders 1–8. It differs from P01DC (over advanced), which some systems derive from the same learning.

Likely causes

Injector of cylinder 9 leaking or over-delivering at small quantities
Engine software (update available for some models)
Injector correction code not or wrongly programmed after replacement
Disturbed crankshaft signal (worn drive belt, tone wheel, dual-mass flywheel)

Symptoms

  • Check engine light on
  • Often nothing noticeable; possibly rough idle or knocking
  • Possibly smoke or higher consumption

Repair estimate

DifficultyHardWorkshop job
Parts and labour€0–1,200
Time0.5–4 h

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

Parts involved

fuel injector cylinder 9crankshaft position sensorengine control module

Related codes

P02DDP01DCP021CP0287P0209P026C

References: law.cornell.edu, gsi.ext.gm.com, patents.google.com.