P1631–P1634 Accelerator Pedal Position Sensor 1 (G79) - Signal too High
The measured signal sits higher than its valid range.
Can you drive it? The engine light will stay on and the car may run in a reduced-power mode. Read the freeze-frame data to see the conditions the fault was logged under.
Which code is which
Same fault, different cylinder or bank — diagnosed the same way. Several set together usually means one shared cause.
| Code | Definition | Severity |
|---|---|---|
P1631 | Accelerator Pedal Position Sensor 1 (G79) - Signal too High | Investigate soon |
P1634 | Accelerator Pedal Position Sensor 2 (G185) - Signal too High | Investigate soon |
The definition
P1631: Accelerator Pedal Position Sensor 1 (G79) - Signal too High.
P1631 is a manufacturer-specific powertrain code (the engine or gearbox). Its meaning is set by the carmaker rather than by the SAE standard, so a generic OBD-II reader will often show it as an unknown code or misread it.
What to check first
Cheapest and fastest checks first:
- Read the freeze-frame data stored with the fault - engine speed, load and temperature at the moment it logged tell you whether this happens cold, hot or under load.
- Check the connector at the part for corrosion, and that it is fully seated.
- Clear the code and see whether it returns, and under what conditions.
What actually causes this on a VAG
G79 is one of the two sensors built into the electronic accelerator pedal, and this code says its signal is reading above anything the ECU considers possible. In practice that means a break in the sensor's earth path - on the potentiometer-type pedals used on the older drive-by-wire cars, losing earth lets the reading float up towards supply voltage - or a signal wire touching a live or the sensor's own 5V feed, or a fault inside the pedal itself. The car will normally go into reduced power with the EPC light on; the system is designed so a pedal fault takes power away rather than adding it. Sometimes it clears itself and the car drives normally again, which is not a sign that the fault has gone away.
Most likely causes, in order
- Corroded connector or broken earth at the pedal. Losing the sensor's earth characteristically drives its reading upwards, and the pedal plug sits low in the driver's footwell where water collects. Unplug it and inspect for corrosion, for a terminal pushed back so it no longer contacts, and for a plug that has never been properly latched. Lift the carpet at the same time and check the underlay is dry - a wet footwell will do this to a new pedal as readily as an old one.
- Signal wire shorted to a supply. Where the loom is pinched under a seat rail, a trim screw or a bracket, a wire can wear through onto the sensor's 5V feed or a live. If this fault started immediately after work in the footwell - a stereo, dashcam, alarm, seat removal or flood repair - make this your first suspect and go straight to whatever was disturbed.
- Pedal module failed. The sensors inside are a wear item and can go open or out of range internally. Watch both pedal channels in live data while pressing slowly; one climbing implausibly high, or jumping, while the other tracks smoothly points at the pedal. It is replaced as a complete sealed assembly.
Worth knowing: Don't just clear this because the car is driving fine again. An intermittent pedal fault drops the car into reduced power without warning, and it will choose its own moment - pulling out of a junction or joining a dual carriageway. Get it diagnosed rather than living with it. Equally, if the code returned straight away after a new pedal was fitted, the problem is in the wiring or the plug, and a second pedal will behave in exactly the same way.
Reading the code is the easy part
A code names the circuit that complained. What tells you why is watching the sensor behind it while the engine runs — and that is where a code reader stops and a diagnostic tool starts.
VAGPULSE reads every module in a VW, Audi, Skoda or SEAT — not just the engine — shows the live measuring blocks behind this fault, gives you the freeze-frame conditions it was logged under, and clears it once you have fixed it. It also does what a generic OBD reader cannot on a VAG: service resets, coding, adaptations, and Stage 1–3 flashing with your original file saved first.
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Common questions
What does P1631 mean?
P1631 means Accelerator Pedal Position Sensor 1 (G79) - Signal too High. The measured signal sits higher than its valid range.
Can I drive with P1631?
The engine light will stay on and the car may run in a reduced-power mode. Read the freeze-frame data to see the conditions the fault was logged under.