What does it mean?
P1122 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: Throttle Position Sensor Intermittent Low Input .
Symptoms
- Sudden brief power loss or a flat spot while accelerating, then normal running again
- Occasional limp mode that clears after a restart
- Check engine light that appears and clears over several drive cycles
- Idle that dips or stalls when the throttle is closed quickly
- Erratic automatic transmission shift behaviour
- Cruise control disengaging without driver input
Likely causes
- Worn or open spot on the resistive track where the wiper loses contact and the signal collapses
- Intermittent short to ground in the signal wire where the loom rubs on the throttle body or a bracket
- Momentary loss of the 5 V reference from a corroded splice or a loose terminal
- Water or corrosion in the connector bridging the signal to ground
- Vibration disturbing a poorly seated connector or a spread terminal
- Sensor loose on the throttle shaft, letting the wiper skip
- Module reference circuit fault, considered last
How to fix it
- Graph the throttle position signal through a slow full sweep and look for momentary drops to zero
- Repeat the test while wiggling the harness and connector to reproduce the dropout
- Check the 5 V reference for stability and inspect its splice points for corrosion
- With the sensor unplugged, measure resistance from the signal wire to ground while flexing the loom
- Inspect the connector for moisture, corrosion and terminals that no longer grip
- Make sure the sensor is properly seated and secured, and that the throttle plate does not bind
- Replace the sensor or throttle body if the dropout follows the sensor, then perform the throttle relearn and confirm a clean sweep