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Code P2120

Symptoms

• Check Engine Light illuminated

• Reduced engine power

• Unresponsive throttle

Common Causes

• Faulty throttle/pedal position sensor

• Damaged wiring or connectors

• ECM malfunction

Glossary

Throttle: The mechanism that controls the amount of air entering the engine.

ECM: Engine Control Module, the computer that manages engine functions.

Related Codes

• P2121

• P2122

Official description

Throttle/Pedal Position Sensor/Switch D Circuit

Laymans terms

This code means that the car's computer detected a problem with the sensor that tells it how much you are pressing the gas pedal.

Explanation

The P2120 code indicates an issue with the throttle/pedal position sensor/switch D circuit, which is responsible for monitoring the position of the throttle or gas pedal.

Technical description

The throttle/pedal position sensor/switch D circuit is a part of the electronic throttle control system. It sends a signal to the engine control module (ECM) indicating the position of the throttle or gas pedal. If the ECM detects a voltage or resistance level outside of the expected range, it triggers the P2120 code.

Diagnosis steps

• Use an OBD-II scanner to confirm the code.

• Inspect the throttle/pedal position sensor and its wiring for damage.

• Test the sensor's voltage and resistance levels.

Repair procedures

• Replace the faulty throttle/pedal position sensor.

• Repair or replace damaged wiring or connectors.

• Reprogram or replace the ECM if necessary.

Tools required

• OBD-II scanner

• Multimeter

• Screwdriver set

Estimated repair cost

$100 - $300

Difficulty level

Moderate

Commonly affected vehicles

• Toyota Camry

• Ford F-150

• Chevrolet Silverado

Preventive measures

• Regularly inspect and maintain the throttle system.

• Ensure connectors are secure and free from corrosion.

• Avoid harsh driving conditions that may damage sensors.

Error code type

Sensor Issue

User experience recommendations

• Do not ignore the Check Engine Light.

• Have the vehicle inspected by a professional.

• Avoid driving at high speeds until the issue is resolved.

Warranty information

Check with the vehicle manufacturer for warranty coverage on throttle system components.

Historical data

The P2120 code has been a common issue in vehicles with electronic throttle control systems since their widespread adoption in the early 2000s.

Urgency level

Moderate – It is advisable to address this issue soon to avoid potential drivability problems.

Legal and safety notice

Driving with a malfunctioning throttle position sensor can lead to reduced engine performance and may pose a safety risk.

Testing conditions

• Engine must be running.

• Throttle system components should be at normal operating temperature.

Component location

The throttle/pedal position sensor is typically located near the throttle body or attached to the accelerator pedal assembly.

FAQs

Q: Can I drive my car with a P2120 code?
A: It's possible, but not recommended as it may lead to reduced engine performance and could be unsafe.

Q: How can I reset the P2120 code?
A: You can use an OBD-II scanner to clear the code, but it's important to fix the underlying issue first.

Last updated: Apr 16, 2026 • Source: internal database
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