P2CAECharge Air Cooler Coolant Pump B Control Circuit Low
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- P2CAE concerns the second electric pump of a charge air cooling loop: its control line is held at ground potential where the driver expects a higher level. No manufacturer documents pump B publicly. GM's published test for pump A (P023B, LT5, table 19OBDG03A) runs with the low-side driver off and flags a short to ground when output and controller ground are connected by less than 0.5 Ω, again 50 of 63 samples, Type A. What the pump then does depends on its design: a plainly switched motor may run all the time, while a smart pump that reads a missing PWM signal may fall back to an emergency mode. Look for a harness chafed on a bracket, water between pins, or an internal short in pump B. The opposite fault, a short to power, is P2CAF.
- What you may notice
- MIL on
- Pump B runs continuously or stays in a fallback mode
- Possible power reduction when the charge air gets hot
- Likely causes
- LikelyControl wire of pump B rubbed through to ground
- PossibleWater or corrosion in the pump B connector
- RareInternal short in the electronics of pump 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: €30 – €700
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.