OBD-II code · Powertrain (generic, extended)

P2431 Secondary Air Injection System Air Flow/Pressure Sensor Circuit

The ECU detects a general fault in the secondary air injection system air flow or pressure sensor circuit. The diagnostic cannot verify proper SAI operation.

Is it safe to drive with P2431?

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

Common causes

  • Most likelyDefective SAI sensor
  • PossibleSAI sensor wiring fault

Repair at a glance

Difficulty
Medium
DIY friendly
Often, with basic tools
Typical labour
0.5–2 h
Emissions test
Likely to fail
After the fix
A drive cycle is needed before the light stays off
Parts involved
Sai Pressure Sensor, Sai Wiring

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