Throttle/Pedal Position Sensor/Switch A Circuit Low

What it means

The engine computer has seen the signal voltage from throttle or pedal position sensor A below the lowest acceptable level. The cause is usually a lost reference voltage or the signal wire shorted to ground, and the computer normally enters limp mode.

Related codes: P0120P0121P0123P2135P0107

Symptoms4

• Check engine light on, possibly with the electronic throttle warning light.
• Limp mode with a severe loss of power.
• Engine not responding normally to the accelerator.
• Unstable idle or stalling.

Possible causes5

• Unplugged or corroded sensor connector.
• Open circuit in the reference voltage wire to the sensor.
• Signal wire shorted to ground.
• Failed sensor or the throttle body it is built into.
• Another sensor sharing the same reference voltage has a short that pulls it down.

How to diagnose5

1. Read all codes; low-voltage codes for other sensors such as P0107 point to a shared reference voltage fault.
2. Watch the sensor signal on a scan tool; a value near zero with the key on means an electrical fault.
3. Inspect the connector and its pins.
4. Measure reference voltage and ground at the connector and compare with the manufacturer specification.
5. Check the signal wire for a short to ground.

How to fix5

1. Clean and reconnect the connector.
2. Repair the open reference wire or the short to ground.
3. Replace any other sensor found pulling down the reference voltage.
4. Replace the sensor, throttle body or pedal assembly depending on the design.
5. Run the relearn procedure if required, then clear the codes and road test.

Repair cost

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 the 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