Powertrain, generic (extended)

P2C9C Cold Start Turbocharger/Supercharger Wastegate Actuator B Range/Performance

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

P2C9C is the counterpart of P2C9B for wastegate B and only exists on engines with two turbochargers: GM's tables define turbo A as the first in a series layout or the bank 1 unit in a parallel one, so B is the second or the bank 2 charger. GM's 4.2-litre twin-turbo V8 (table 19OBDG07, test group KGMXV04.2088) watches the bank 2 turbine bypass valve during the cold-start rapid heat-up mode; if the valve is detected as jammed for more than 1 s, P2C9C sets, with separate paths for positions up to 50 % and above. The single-turbo 2.7-litre L3B has only actuator A, so 19OBDG03D lists no P2C9C. A valve that does not open while warming up delays catalyst light-off and raises cold-start emissions. Check the bank 2 actuator, linkage and plug; P2B94 is the learn limit of wastegate B.

Likely causes

Bank 2 wastegate flap or linkage stiff from corrosion or deposits
Worn or weak wastegate actuator B
Wiring or connector fault at actuator B

Symptoms

  • Check engine light shortly after a cold start
  • Uneven boost between banks later in the drive
  • Often no noticeable change during the cold start

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€80–1,800
Time0.5–4 h

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

Parts involved

wastegate actuator becm

Related codes

P2C9BP2B82P2B94P050E

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