What does it mean?
P1125 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: Throttle/Pedal Position Sensor Circuit Plausibility Error .
Symptoms
- Malfunction indicator lamp on, frequently with the fault appearing and clearing on its own
- Sudden drops into limp mode while driving, often recovering after a restart
- Momentary loss of throttle response over bumps or during hard cornering
- Erratic idle speed that changes without any pedal input
- Cruise control cutting out unexpectedly
Likely causes
- Intermittent break in one of the two signal circuits, often inside a flexing section of harness
- Water or corrosion bridging terminals in the throttle body or pedal connector
- Failure of one track inside a dual-track sensor while the other still reports normally
- Loose or backed-out terminal in the connector that makes and breaks with vibration
- Shared reference or ground circuit with high resistance, shifting only one of the two signals
- Mechanical binding of the throttle plate so the actual angle no longer matches the commanded value
- Electrical interference from a poorly grounded accessory or an aftermarket electrical add-on
How to fix it
- Check freeze frame for road speed, engine load and coolant temperature to learn when the mismatch occurs
- Graph both position signals side by side on the scan tool; they should track each other proportionally through the whole sweep
- Wiggle the pedal and throttle harness with the ignition on and watch for a momentary split between the two traces
- Open the connectors and check for moisture, corrosion and terminal tension using a matching test pin
- Measure resistance of each signal circuit end to end and the shared ground with the connectors disconnected
- Confirm the throttle plate moves freely by hand with the actuator unpowered
- Replace the sensor or pedal assembly only after the harness proves good, then relearn and road test