P2122

Throttle/Pedal Position Sensor/Switch D Circuit Low

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 is below its normal range. On most vehicles, sensor D is the first sensor in the accelerator pedal position sensor. The computer then cannot trust the driver's request, so it enters limp mode and limits power.

Symptoms4

Check engine light on, sometimes with the electronic throttle warning light.
Weak acceleration and limp mode.
Delayed or limited response to the accelerator.
Engine held at idle in some cases.

Possible causes5

Corroded or loose pedal sensor connector.
Open in the sensor signal wire or reference voltage wire.
Signal wire shorted to ground.
Failed sensor D inside the pedal sensor assembly.
Reference voltage from the engine computer (ECU) pulled down by a short in another sensor that shares the same supply.

How to diagnose5

Read all stored codes; a reference voltage code such as P0641 points to a shared supply fault.
Watch the sensor D voltage on a scan tool while pressing the pedal slowly; it should change smoothly without dropouts.
Inspect the pedal sensor connector for corrosion or loose pins.
Measure the reference voltage and ground at the connector and compare them with the manufacturer specification.
Check signal wire continuity and confirm there is no short to ground.

How to fix5

Clean or repair the connector and secure it properly.
Repair the broken or shorted wire.
Fix the cause of low reference voltage if another sensor is shorting it.
Replace the pedal sensor, which usually comes as one assembly with the pedal.
Clear the codes, perform a relearn if the manufacturer requires it, and confirm the code does not return.

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 wiring 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

Why are there two sensors in the accelerator pedal?

For safety. The computer constantly compares both signals, and if one disagrees or goes out of range it enters limp mode to prevent unintended acceleration.

Can I drive with this code?

Carefully and only a short distance to a workshop, since power is limited and pedal response is not normal.

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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