P0120

Throttle/Pedal Position Sensor/Switch A Circuit

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 – 2 hours

Typical cost SAR 100 to 2,500

What it means

The engine computer has detected an invalid signal from sensor A, which measures the position of the throttle or the accelerator pedal. Because this signal is essential for controlling engine power, the computer usually enters a protective limp mode that limits engine speed and power.

Symptoms5

Check engine light on, sometimes with the electronic throttle warning light.
Limp mode with a severe loss of power.
No response or delayed response to the accelerator.
Unstable idle or stalling.
Abnormal shifting in an automatic transmission.

Possible causes6

Unplugged or corroded sensor connector.
Open or shorted sensor wiring.
Worn sensing track inside the sensor.
Fault in the reference voltage or ground shared with other sensors.
Failed electronic throttle body when the sensor is built into it.
Engine computer fault (rare).

How to diagnose5

Read all codes; codes for other sensors sharing the same reference voltage point to a reference fault.
Watch the sensor signal on a scan tool while slowly opening the throttle or pressing the pedal; it should rise smoothly without jumps.
Inspect the connector and wiring visually.
Measure reference voltage, ground and signal at the connector and compare with the manufacturer specification.
Confirm whether sensor A is on the throttle body or the pedal for this vehicle before replacing any part.

How to fix5

Clean and reconnect the connector.
Repair the open or shorted wire.
Fix the reference voltage fault if it affects several sensors.
Replace the sensor, or the throttle body or pedal assembly if the sensor is built in.
Run the throttle relearn procedure if the vehicle requires it, then clear the codes and road test.

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 wire repair, and reaches the upper end when a complete electronic throttle body 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

Can I drive with this code?

Carefully and only a short distance, because the car can suddenly enter limp mode and lose power, which is dangerous when overtaking or on highways.

Is the sensor on the throttle or the pedal?

This code covers both depending on the vehicle design, so the technician confirms where sensor A is from the manufacturer information before repairing.

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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