P2123

Throttle/Pedal Position Sensor/Switch D Circuit High

Car Fault Codes Fuel & air

Can you still drive? With care, short trips only

Who can fix it? Needs a workshop

Typical repair time 30 minutes – 1.5 hours

Typical cost SAR 100 to 900

What it means

The engine computer has found that the signal from sensor D, usually the first sensor in the accelerator pedal position sensor, is above its normal range. This is usually caused by an open ground wire or a signal wire shorted to a voltage source, and the engine enters limp mode.

Symptoms4

Check engine light on, sometimes with the electronic throttle warning light.
Loss of power and limp mode.
Abnormal accelerator response.
Engine held at idle in some cases.

Possible causes5

Open in the sensor ground wire.
Signal wire shorted to a power wire or voltage source.
Moisture or corrosion in the sensor connector.
Failed sensor D inside the pedal sensor assembly.
Engine computer (ECU) fault, which is rare.

How to diagnose5

Watch the sensor D voltage on a scan tool with the pedal released and while pressing slowly, and compare it with the normal range.
Inspect the connector for moisture or corrosion.
Check ground wire continuity between the sensor and the computer.
Unplug the sensor and confirm the signal wire is not carrying voltage from another source.
Compare the sensor D reading with sensor E to see whether only one sensor is affected.

How to fix5

Dry and clean the connector, or replace it if corroded.
Repair the open ground wire.
Repair the shorted wire and separate it from the voltage source.
Replace the pedal sensor or the complete pedal assembly if it is proven faulty.
Clear the codes and confirm normal power returns and the code does not come back.

Repair cost

0–500

500–2,000

2,000–5,000

5,000+

In Saudi riyals; the highlighted part is the expected range for this fault.

The cost is low for a connector or ground wire repair, and rises when the pedal assembly with its sensor is replaced.

Prices are rough estimates for common cars at independent workshops and vary with the car and the source of the part.
Prices last updated: September 2026

Frequently asked questions

Does this code mean the pedal reads as fully pressed?

No. It means the signal went outside its normal limits, so the computer distrusts it and limits power instead of treating it as full throttle.

Can the sensor be repaired instead of replaced?

Usually not, since the sensor is built into the pedal on most vehicles. But check the connector and wiring first, as they may be the cause.

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This guide is for information only and does not replace an inspection by a qualified technician. If the fault involves brakes, steering, engine temperature, electrics or refrigerant, do not attempt the repair yourself.

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