AutoCodes – Toyota – P1129 Toyota

P1129 Toyota Code - Electric Throttle Control System Malfunction

Quick Answer

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. Common causes include 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. 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 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.
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.
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Code Popularity 18,200
How popular is this code, among other codes? Low
Table of contents Created and updated by William Orellana on Aug 15, 2019
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Code P1129 Toyota Description

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.
OBDII Code P1129 Toyota - Electric Throttle Control System Malfunction - AutoCodes.com
P1129 Toyota Code - Electric Throttle Control System Malfunction

What are the Possible Causes of the DTC P1129 Toyota?

  • 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 to Fix the DTC P1129 Toyota?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P1129 Toyota code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

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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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