OBD-II code · Powertrain (generic, extended)

P2AC0 Intake Air O2 Sensor Reference Voltage Circuit Range/Performance Bank 1

The reference voltage supplied to the intake air oxygen sensor on bank 1 reports a range/performance condition. Lambda measurement on the intake side is unreliable.

Is it safe to drive with P2AC0?

Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.

Common causes

  • Most likelyReference voltage drifted from nominal
  • PossibleHigh-resistance contact in connector
  • Less likelySensor element aged beyond calibration window

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 B1, Wiring Harness, Ecm

Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.