P2431: AIR System Air Flow/Pressure Sensor Circuit Range/Performance Bank 1 — what it means, the affected system and what to check before replacing parts.
Meaning, symptoms, causes and checks
AIR System Air Flow/Pressure Sensor Circuit Range/Performance Bank 1. Basic catalogue definition; diagnostic details have not yet been reviewed.
Affected system: Powertrain
Symptoms
- A fault lamp can appear together with uneven idling or difficult running after a cold start.
- Noise from the secondary-air equipment or reduced engine smoothness may be reported, but symptoms vary.
Possible causes
- Insufficient secondary-air pump output or a sticking one-way or air-control valve may distort the observed pressure/flow.
- A faulty pressure sensor, damaged harness or loose connector may also produce implausible feedback.
What to check
- Confirm P2431 and record companion faults before testing.
- Inspect the pressure-sensor connector and the secondary-air harness; check for visible damage.
- Verify pump operation, then assess the check valve and air-control valve; compare sensor feedback with the vehicle-specific test procedure.
Also written as: P2431-00, P243100 (some scan tools add the fault-type byte, e.g. -00).