Engine-Codes - Lexus - P1129 LEXUS

P1129 LEXUS - Electric Throttle Control System Malfunction

Repair Importance Level: 3/3
Repair Difficulty Level: 2/3  What is this?
Table of contents

P1129 LEXUS Possible Causes

  • Faulty Electronic Throttle Control System (ETCS) Actuator
  • Electronic Throttle Control System (ETCS) Actuator harness is open or shorted
  • Electronic Throttle Control System (ETCS) Actuator circuit poor electrical connection

How is the P1129 LEXUS code repair?

Start by checking the "Possible Causes" listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector's pins.

What is the cost to diagnose the P1129 LEXUS code

Labor: 1.0

The cost to diagnose the P1129 LEXUS code is 1.0 hour of labor. The auto repair labor rates vary widely across the country, and even within the same city. Most auto repairs shops charge between $75 and $150 per hour.
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When is the code detected?

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

Possible Symptoms

  • Engine Light ON (or Service Engine Soon Warning Light)

P1129 LEXUS Meaning

Electric Throttle Control System (ETCS) is composed of the throttle motor to operate the throttle valve, the electromagnetic clutch to connect the throttle motor with the throttle valve, the throttle position sensor to detect the opening angle of the throttle valve, the accelerator pedal position sensor to detect the accelerator pedal position, the Engine Control Module (ECM) to control the ETCS and the one valve type throttle body.
The ECM controls the throttle motor to make the throttle valve opening angle properly in response driving condition.
The throttle position sensor which is mounted on the throttle body detects the opening angle of the throttle valve, and it provides feedback to the ECM to control the throttle motor.
If the ETCS has a malfunction, the ECM shuts down the power for the throttle motor and the magnetic clutch, and the throttle valve is fully closed by the return spring.
However, the opening angle of the throttle valve can be controlled by the accelerator pedal through the throttle cable.

More Information

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