OBD-II code · Powertrain (generic, extended)
P2AC9 Charge Air Cooler Coolant Temperature Sensor B Circuit Low
Voltage on the charge air cooler coolant temperature B sensor signal line is below the expected window. Wire shorted to ground or sensor short.
Is it safe to drive with P2AC9?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelySignal wire shorted to ground
- PossibleInternal sensor short
- Less likelyConnector pins corroded - high contact resistance
Repair at a glance
- Difficulty
- Easy
- DIY friendly
- Often, with basic tools
- Typical labour
- 0.3–1.5 h
- Emissions test
- Usually unaffected
- Parts involved
- Charge Air Cooler Coolant Temp Sensor B, Wiring Harness, Ecm
Related codes
- P00E0Charge Air Cooler Coolant Temperature Sensor A Circuit Low
- P2AC6Intake Air O2 Sensor Reference Voltage Circuit High Bank 2
- P2AC7Charge Air Cooler Coolant Temperature Sensor B Circuit
- P2AC8Charge Air Cooler Coolant Temperature Sensor B Range/Performance
- P2ACACharge Air Cooler Coolant Temperature Sensor B Circuit High
- P2ACBCharge Air Cooler Coolant Temperature Sensor B Circuit Intermittent/Erratic
- P2ACCReductant Temperature Sensor B Circuit
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.