P2433
Secondary Air Injection System Air Flow/Pressure Sensor Circuit High (Bank 1)
- Severity
- Low
- Driving
- Drivable — book it in
The secondary air flow or pressure sensor signal on bank 1 is stuck high - typically shorted to voltage or with a lost earth, though a genuinely blocked passage can also raise pressure beyond what the module expects.
Possible causes
- CommonWiring shorted to voltage, or a lost sensor earth
- CommonCorroded connector bridging pins
- CommonFailed sensor
- CommonBlocked passage raising pressure against the pump
- PossibleChafed harness against a supply wire
What you might notice
- Check engine light on
- Failed emissions test
- Pump sounding strained on a cold start
- Usually no symptom the driver notices
What to check, in order
- Listen to the pump on a cold start. A pump straining against a blockage sounds different from one running freely, and that supports a genuine pressure reading rather than an electrical fault.
- Check the sensor earth before assuming a shorted signal wire.
- Unplug the sensor and check whether the high reading persists at the harness.
- Inspect the air passages into the exhaust manifold for carbon.
- Inspect the connector for corrosion bridging pins.
Read this code from your own car
Plug an ELM327 adapter into the OBD-II port under the dashboard. Pin16 reads every stored, pending and permanent code, explains each one like this page does — offline, with no account — and shows what the car recorded when the fault was set.
Where this code sits
P00xxP01xxP02xxP03xxP04xxP05xxP06xxP07xxP08xxP09xxP0AxxP0BxxP0CxxP0DxxP0ExxP0FxxP10xxP11xxP12xxP13xxP14xxP15xxP16xxP17xxP18xxP19xxP1AxxP1BxxP1CxxP1DxxP1ExxP1FxxP20xxP21xxP22xxP23xxP24xxP25xxP26xxP27xxP28xxP29xxP2AxxP2BxxP2CxxP2DxxP2ExxP2FxxP30xxP31xxP32xxP33xxP34xxP35xxP36xxP37xxP38xxP39xxP3AxxP3BxxP3CxxP3DxxP3ExxP3Fxx