Engine-CodesToyota – P1129 Toyota

P1129 Toyota Code - Electric Throttle Control System Malfunction

Quick Answer

The P1129 code for Toyota vehicles indicates a malfunction in the Electric Throttle Control System. Common causes include Faulty throttle position sensor, Wiring or connector issues in the throttle control system, Electronic control unit (ECU) malfunction. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means
P1129 Toyota indicates Electric Throttle Control System Malfunction.
Common causes
Common causes include Faulty throttle position sensor, Wiring or connector issues in the throttle control system, Electronic control unit (ECU) malfunction.
Severity
High - diagnose this code as soon as possible.
Can I drive?
Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
Table of contents Created and updated by William Orellana on Aug 25, 2024
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Code P1129 Toyota Description

The P1129 code for Toyota vehicles indicates a malfunction in the Electric Throttle Control System. This system is responsible for managing the throttle opening angle based on driver input and various sensor readings. When this system malfunctions, it can lead to erratic engine performance, poor fuel efficiency, and potential safety hazards. The throttle control system plays a crucial role in regulating the engine's air intake, fuel injection, and overall power output.

OBDII Code P1129 Toyota - Electric Throttle Control System Malfunction
P1129 Toyota Code - Electric Throttle Control System Malfunction

Common Causes of P1129 Toyota

  1. Faulty throttle position sensor
  2. Wiring or connector issues in the throttle control system
  3. Electronic control unit (ECU) malfunction
  4. Vacuum leak in the intake system
  5. Dirt or debris affecting the throttle body

Symptoms of P1129 Toyota

  1. Reduced engine power
  2. Hesitation or jerking during acceleration
  3. Engine stalling or rough idling
  4. Illuminated Check Engine Light
  5. Limited or unresponsive throttle response

How to Fix P1129 Toyota

  1. Diagnose the specific cause of the Electric Throttle Control System malfunction using a scan tool to retrieve fault codes and testing components like the throttle position sensor.
  2. Inspect wiring and connectors for any signs of damage or corrosion, repairing or replacing as needed.
  3. Clean the throttle body to remove any buildup of dirt or debris that could be affecting its function.
  4. Replace the throttle position sensor or electronic control unit if they are determined to be faulty.
  5. Reset the ECU and perform a throttle relearn procedure to ensure proper calibration.

Cost to Fix P1129 Toyota

The typical repair costs for resolving a P1129 code can range from $200 to $600, including parts and labor. However, actual costs may vary based on the specific diagnosis time and labor rates at auto repair shops, which can range from $80 to $150 per hour. Factors such as the vehicle make and model, location, and engine type can also impact the overall repair costs. It's recommended to obtain quotes from multiple shops to compare prices and ensure a competitive rate for the repair.

When is the Code Detected?

The P1129 code is set when the throttle opening angle continues to vary great from target throttle opening angle.

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About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

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