P0303MinorAuxiliary Emission Controls

Code P0303 — Auxiliary Emission Controls

Diagnostic trouble code P0303 indicates a fault in the Auxiliary Emission Controls system. This code is detected by the vehicle's onboard diagnostic system and requires professional diagnosis.

Common Causes

  • ▸Faulty sensor or wiring
  • ▸Software or calibration issue
  • ▸Mechanical component failure