What does it mean?
P1142 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: Throttle Position Sensor Circuit Range/Performance Problem (low input) .
Symptoms
- Malfunction indicator lamp on with reduced power or a limited rev range
- Engine hesitating or bogging when the pedal is pressed from idle
- Idle speed too low, unstable, or the engine stalling at a stop
- Automatic transmission holding gears or shifting late
- Poor throttle response even though the pedal moves normally
Likely causes
- Open or high resistance in the 5 V reference circuit feeding the sensor
- Signal wire shorted to ground or to the sensor ground circuit
- Worn low-angle section of the resistive track, giving a dead spot near closed throttle
- Loose or corroded terminals in the sensor connector reducing signal voltage
- Sensor rotated out of position or its mounting screws loose
- Damaged internal wiper contact inside the sensor body
- Water ingress into the connector after washing the engine bay
How to fix it
- Read the throttle position value in percent and volts at closed throttle and compare it with specification
- Slowly open the throttle by hand and watch for a dropout to zero in live data
- Measure the 5 V reference and ground at the sensor connector with the key on and the sensor unplugged
- Back probe the signal wire at the PCM to see whether the low reading is present at the module too
- Test the signal circuit for a short to ground with the sensor disconnected
- Check the sensor mounting, alignment and screw tightness before replacing anything
- Replace the sensor if the track proves worn, then perform the throttle relearn and verify idle values