What does it mean?
P1280 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: Accelerator Pedal Position Sensor 2 Circuit Malfunction .
Symptoms
- The MIL is on, usually with a correlation code stored as well
- Reduced power mode with a low rev ceiling
- Weak or missing response to the accelerator pedal
- Idle higher than normal or unstable
- Cruise control disabled
- Fault may come and go with vibration or when the pedal is pressed hard
Likely causes
- Open circuit, short to ground or short to voltage in the sensor 2 signal wire
- Missing 5 volt reference or ground for the second sensor track
- Corroded or damp terminals in the pedal connector
- Worn track inside the pedal unit giving dropouts on the second signal
- Loom damage under the carpet, at the bulkhead or where the pedal moves
- Poorly made repair joint or an accessory tapped into the pedal wiring
- Faulty pedal sensor assembly or, rarely, a module input fault
How to fix it
- Watch sensor 2 on live data through a slow full pedal sweep and compare it with sensor 1
- Inspect the pedal connector for damp, corroded and pushed-back terminals
- Measure the reference voltage and ground for the second track with the ignition on
- Back-probe the sensor 2 signal wire and record the voltage at rest and at wide open pedal
- Test the signal wire for continuity and for shorts to ground and voltage with the connectors unplugged
- Wiggle the loom while monitoring live data to expose an intermittent fault
- Replace the pedal sensor assembly when the wiring is proven, then carry out the learn procedure and verify both signals track together