Powertrain, generic (extended)

P2DDD Fuel Injection Quantity C Higher Than Expected

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

P2DDD flags excess fuel from injection path C: the quantity really burned, as estimated from airflow and lambda, sits above the request. Besides the classic leaking injector, a possible trigger after repairs is a replacement injector whose individual flow code was not programmed into the engine control, so the module calculates with the wrong flow curve. Another is an EGR valve that leaves too little fresh air, which the estimate can read as surplus fuel. GM lets its system-A adaptation take away only about 8 to 14 mm³, depending on speed and load. No manufacturer documents P2DDD publicly. P2DDC is the shortfall in path C, P2DE1 the cold-start excess; smoke and higher consumption are what drivers notice.

Likely causes

Injector of group C leaking or nozzle worn
Injector correction code not programmed after replacement
EGR valve not closing fully, too little fresh air

Symptoms

  • Check engine light on
  • Dark smoke under load
  • Higher fuel consumption

Repair estimate

DifficultyHardWorkshop job
Parts and labour€100–3,500
Time0.5–5 h

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

Parts involved

fuel injector group cfuel railecm

Related codes

P2DDCP2DE1P2DD6P2DDFP026D

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