AutoCodes – Toyota – U0129 2017 Toyota RAV4

U0129 2017 Toyota RAV4 Code - Lost Communication with Brake System Control Module

Quick Answer

The Controller Area Network (CAN) is a standard bus system in vehicles that enables the connection of automotive devices without the need for a host computer. Common causes include Faulty Controller Area Network (CAN) Communication System, Faulty Brake System Control Module, Brake System Control Module harness is open or shorted. 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: U0129 2017 Toyota RAV4 indicates Lost Communication with Brake System Control Module.
Common causes: Common causes include Faulty Controller Area Network (CAN) Communication System, Faulty Brake System Control Module, Brake System Control Module harness is open or shorted.
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 362

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Mar 26, 2023

Description
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code U0129 2017 Toyota RAV4 Description

The Controller Area Network (CAN) is a standard bus system in vehicles that enables the connection of automotive devices without the need for a host computer. The exchange of operating information and commands among devices is facilitated by pre-programmed information about the required message exchange on the serial data circuits. Communication is carried out using two dedicated wires, known as CAN high and CAN low, with both lines carrying 2.5V when the CAN bus is in idle mode. During the transmission of data bits, the CAN high line increases to 3.75V while the CAN low drops to 1.25V, creating a 2.5V differential between the lines. Since communication relies on a voltage differential between the two bus lines, the CAN bus is NOT sensitive to inductive spikes, electrical fields, or other noise. The Diagnostic Trouble Code (DTC) sets when a periodic message from the Brake System Control Module has not been received.

OBDII Code U0129 2017 Toyota RAV4 - Lost Communication with Brake System Control Module - AutoCodes.com — U0129 2017 Toyota RAV4 Code - Lost Communication with Brake System Control Module

What does this mean?

What are the Possible Causes of the DTC U0129 2017 Toyota RAV4?

Faulty Controller Area Network (CAN) Communication System
Faulty Brake System Control Module
Brake System Control Module harness is open or shorted
Brake System Control Module circuit poor electrical connection

How to Fix the DTC U0129 2017 Toyota RAV4?

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 does this mean?

Code Tech Notes

When there are problems with the way different systems in a vehicle communicate with each other using a technology called Controller Area Network (CAN) communication, Diagnostic Trouble Codes (DTC) are displayed. These codes can be caused by issues with the main bus or branch of the communication network, or with the Electronic Control Units (ECUs) and sensors that make up the different systems. If you see code for both the CAN communication problems and internal or power source problems at the same time, you should focus on fixing the internal or power source problems first.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the U0129 2017 Toyota RAV4 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.

Frequently Asked Questions about U0129 2017 Toyota RAV4 Code

1. What are the common symptoms of OBDII code U0129 in a 2017 Toyota RAV4?

The common symptoms include the ABS warning light illuminated on the dashboard, loss of communication with the brake system control module, and potential issues with the vehicle's brake system functionality.

2. What causes the U0129 code (Lost Communication with Brake System Control Module) in a 2017 Toyota RAV4?

The U0129 code is usually caused by wiring issues, damaged connectors, a faulty brake system control module, or a malfunction in the communication network between the various control modules in the vehicle.

3. How can I diagnose the U0129 code in my 2017 Toyota RAV4?

Diagnosing the U0129 code typically involves using an OBDII scanner to retrieve the code, checking the wiring and connectors for any visible damage, and performing a thorough inspection of the brake system control module.

4. Can I still drive my 2017 Toyota RAV4 with the U0129 code active?

It is not recommended to drive your vehicle with the U0129 code active, as it indicates a communication failure with the brake system control module, which can affect the proper functioning of the vehicle's braking system.

5. How do I repair the U0129 code in my 2017 Toyota RAV4?

To repair the U0129 code, you may need to repair or replace damaged wiring and connectors, troubleshoot the brake system control module for faults, or reset the communication network between the control modules in the vehicle.

6. Is it safe to continue driving if the U0129 code (Lost Communication with Brake System Control Module) appears intermittently?

It is not advisable to continue driving if the U0129 code appears intermittently, as it indicates a potential issue with the communication between the brake system control module and other vehicle systems, which can compromise safety.

7. Can a DIY enthusiast fix the U0129 code in a 2017 Toyota RAV4?

While some basic troubleshooting steps can be performed by a DIY enthusiast, diagnosing and repairing the U0129 code may require specialized tools and expertise, so it is advisable to consult a professional mechanic.

8. How much does it cost to fix the U0129 code in a 2017 Toyota RAV4?

The cost of fixing the U0129 code can vary depending on the underlying cause of the issue. It may range from a simple repair of wiring/connectors to a replacement of the brake system control module, costing anywhere from $100 to $500 or more.

9. Will resetting the fault codes make the U0129 code disappear permanently?

Simply resetting the fault codes may temporarily clear the U0129 code, but if the underlying issue causing the communication loss with the brake system control module is not addressed, the code is likely to reappear.

10. Can extreme weather conditions trigger the U0129 code in a 2017 Toyota RAV4?

Extreme weather conditions such as excessive heat or moisture can potentially cause electrical issues leading to the U0129 code. It is essential to ensure all components are properly sealed and protected from environmental factors to prevent such occurrences.