P2AC2
Intake Air O2 Sensor Reference Voltage Circuit High Bank 1
The reference voltage supplied to the intake air oxygen sensor on bank 1 reports a high condition. Lambda measurement on the intake side is unreliable.
The reference voltage supplied to the intake air oxygen sensor on bank 1 reports a high condition. Lambda measurement on the intake side is unreliable.
Common causes
- high
Reference wire shorted to B+
One of the most commonly reported causes for this code — check this first.
Typical part cost: $220-990
- medium
Sensor reference regulator overvoltage
A plausible cause — test and verify before replacing parts.
Typical part cost: $220-990
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First things to check
- 1Confirm the code with a scan tool and check for additional related codes.
- 2Inspect the relevant sensors, wiring, and connectors for damage or corrosion.
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Related codes
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Frequently asked questions
What does P2AC2 mean?
P2AC2 means "Intake Air O2 Sensor Reference Voltage Circuit High Bank 1". It is a generic OBD-II code that points to a fault in the auxiliary emission controls.
What are the most common causes of P2AC2?
reference wire shorted to b+; sensor reference regulator overvoltage; connector pins corroded - high contact resistance — these are the most commonly reported causes. Verify with a proper diagnosis before replacing parts, or use the Wrenchify app for a vehicle-specific diagnosis.
Can I keep driving with this code?
The vehicle is usually drivable for short distances, but the problem can worsen or affect emissions. Diagnose and repair as soon as practical. Use the Wrenchify app for a full diagnosis specific to your vehicle.
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