P2AC1

Intake Air O2 Sensor Reference Voltage Circuit Low Bank 1

Severity

⚠️ Medium

Can you drive?

Yes, but get it checked soon

Approx. repair cost

$28–89 (est.)

Symptoms

Check Engine light comes on
Increased fuel consumption
Reduced engine power
Unstable idling
Dips during acceleration

Causes

Open or short circuit in the sensor circuit
Poor contact in the sensor connector
Malfunction of the oxygen sensor itself
Problems with power or grounding of the circuit
Engine ECU malfunction

How to Fix

Check the integrity of wiring and connectors
Measure the resistance and voltage in the sensor circuit
Check the reference voltage at the sensor
Replace the oxygen sensor if necessary
Check and clean contacts in connectors

Related codes

P2AC2 P2AC0 P2AC3