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Engine-Codes – Lexus – P1129 Lexus

P1129 Lexus Code - Electric Throttle Control System Malfunction

Quick Answer

The P1129 code for Lexus 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, Dirty or clogged throttle body. 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 Lexus indicates Electric Throttle Control System Malfunction.
Common causes
Common causes include Faulty throttle position sensor, Wiring or connector issues in the throttle control system, Dirty or clogged throttle body.
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.
What is this?
Table of contents Created and updated by William Orellana on Sep 05, 2024
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Code P1129 Lexus Description

The P1129 code for Lexus vehicles indicates a malfunction in the Electric Throttle Control System. This system is responsible for controlling the throttle opening in response to driver inputs and various engine conditions. When this system malfunctions, it can lead to poor engine performance, reduced fuel efficiency, and potential safety hazards.

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

Common Causes of P1129 Lexus

  1. Faulty throttle position sensor
  2. Wiring or connector issues in the throttle control system
  3. Dirty or clogged throttle body
  4. Electronic control unit (ECU) malfunction
  5. Vacuum leaks in the intake system

Symptoms of P1129 Lexus

  1. Rough idling
  2. Engine stalling
  3. Hesitation during acceleration
  4. Reduced engine power
  5. Vehicle going into limp mode

How to Fix P1129 Lexus

  1. Diagnose the issue using a scan tool to pinpoint the exact cause of the malfunction.
  2. Inspect and test the throttle position sensor, wiring, and connectors for any faults.
  3. Clean or replace the throttle body if it is dirty or clogged.
  4. Check the electronic control unit (ECU) for proper functioning and replace if necessary.
  5. Repair any vacuum leaks in the intake system that may be affecting the throttle control.

Cost to Fix P1129 Lexus

The typical repair costs for addressing a P1129 code in a Lexus vehicle can range from $200 to $600, including parts and labor. However, it's important to note that actual costs can vary based on the specific diagnosis time and labor rates at auto repair shops. It's recommended to obtain quotes from multiple shops to ensure a fair price 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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