P2124: Throttle/Pedal Position Sensor/Switch D Circuit Intermittent
Do not keep driving
If the car briefly loses power and then recovers, treat it as more urgent than an intermittent fault normally deserves — a momentary loss mid-overtake is worse than a permanent one. Mention whether it relates to pedal position or to bumps.
What this code means
Sensor D's signal drops out or jumps briefly. Because the module withdraws throttle authority whenever it cannot trust the pedal, even a momentary dropout produces a moment of reduced power — so the experience is a car that briefly goes flat and then recovers, often several times a journey.
That is unpleasant and it is also a safety consideration in its own right: a momentary loss of power part-way through an overtake is worse than a permanent one, because the permanent version does not let you start the overtake.
A connector that is corroded but not yet failed, or a harness flexing as the pedal moves, are the usual causes.
Likely causes
Start here
- Corroded accelerator pedal connector · easy
- Damaged wiring harness · moderate
- Faulty accelerator pedal position sensor · easy
Less common
- Water ingress into the footwell · moderate
Symptoms
Components involved
Information, not instruction
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Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
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