OBD-II code · Powertrain (generic, extended)
P2AC5 Intake Air O2 Sensor Reference Voltage Circuit Low Bank 2
The reference voltage supplied to the intake air oxygen sensor on bank 2 reports a low condition. Lambda measurement on the intake side is unreliable.
Is it safe to drive with P2AC5?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyReference wire shorted to ground
- PossibleInternal short in sensor reference
- Less likelyConnector pins corroded - high contact resistance
Symptoms
- Check engine light on
- Increased fuel consumption
- Possible rough idle or hesitation
- Failed emissions test
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Best left to a mechanic
- Typical labour
- 1–4 h
- Emissions test
- Likely to fail
- After the fix
- A drive cycle is needed before the light stays off
- Parts involved
- Intake Air O2 Sensor B2, Wiring Harness, Ecm
Related codes
- P2AC1Intake Air O2 Sensor Reference Voltage Circuit Low Bank 1
- P2AC2Intake Air O2 Sensor Reference Voltage Circuit High Bank 1
- P2AC3Intake Air O2 Sensor Reference Voltage Circuit/Open Bank 2
- P2AC4Intake Air O2 Sensor Reference Voltage Circuit Range/Performance Bank 2
- 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
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.