P2135

Throttle/Pedal Position Sensor/Switch A/B Voltage Correlation

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

On most vehicles, sensors A and B are the two throttle position sensors inside the throttle body. The engine computer constantly compares their signals and has found that they no longer agree as they should, so it no longer trusts the throttle position and enters limp mode.

Symptoms4

Check engine light on, sometimes with the electronic throttle warning light.
Loss of power and limp mode.
Unstable idle or occasional stalling.
Stumbling or hesitation on acceleration if the fault is intermittent.

Possible causes5

Corroded or loose throttle body connector.
Worn sensor track inside the throttle body at a certain position.
High resistance in the shared ground or reference voltage wire.
Moisture in the connector or throttle body.
Engine computer (ECU) fault, which is rare.

How to diagnose5

Read all stored codes; single-sensor codes such as P0122 or P0222 identify the faulty sensor.
Watch both A and B signals on a scan tool with the key on while pressing the pedal slowly, and look for a jump or dropout in either one.
Inspect the throttle body connector for corrosion, moisture or loose pins.
Measure the reference voltage and ground at the connector and compare them with the manufacturer specification.
Wiggle the wiring while watching the readings to find an intermittent fault.

How to fix5

Clean or repair the connector and secure it properly.
Repair the ground or reference wire if its resistance is high.
Replace the throttle body if its built-in sensor is faulty, then perform the relearn.
Replace the throttle position sensor alone if it is a separate part on your vehicle.
Clear the codes 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 reaches the upper end when the throttle body with both built-in sensors 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 does the throttle need two sensors?

For safety. The computer confirms the throttle position by comparing both sensors, and if they disagree it cannot tell which is right, so it limits power.

Will a throttle body cleaning fix it?

Usually not, because this is an electrical code about the sensors or connector, not carbon. Check the connector and wiring before replacing the throttle body.

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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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