P2C9CCold Start Turbocharger/Supercharger Wastegate Actuator B Range/Performance
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Needs a drive cycle to confirm a fix
- How the car detects it
- 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.
- What you may notice
- Check engine light shortly after a cold start
- Uneven boost between banks later in the drive
- Often no noticeable change during the cold start
- Likely causes
- LikelyBank 2 wastegate flap or linkage stiff from corrosion or deposits
- PossibleWorn or weak wastegate actuator B
- RareWiring or connector fault at actuator B
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €80 – €1,800
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.