AutoCodes – Toyota – U0129 2014 Toyota RAV4

U0129 2014 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 2014 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 303

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 2014 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 2014 Toyota RAV4 - Lost Communication with Brake System Control Module - AutoCodes.com — U0129 2014 Toyota RAV4 Code - Lost Communication with Brake System Control Module

What does this mean?

What are the Possible Causes of the DTC U0129 2014 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 2014 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 2014 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 2014 Toyota RAV4 Code

1. What does the OBDII code U0129 mean on a 2014 Toyota RAV4?

The code U0129 indicates a communication problem between the vehicle's engine control module (ECM) and the brake system control module.

2. What are the common symptoms of U0129 on a Toyota RAV4?

Common symptoms of U0129 include the ABS warning light, traction control light, or brake warning light illuminating on the dashboard. Additionally, you may experience issues with the ABS system or traction control system.

3. What are the possible causes of U0129 on a 2014 Toyota RAV4?

Possible causes of U0129 include a faulty brake system control module, damaged wiring or connectors, a software glitch, or a communication network issue within the vehicle.

4. How can I diagnose the U0129 code on my Toyota RAV4?

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

5. Can I still drive my Toyota RAV4 with the U0129 code?

It is not recommended to drive your Toyota RAV4 with the U0129 code present, as it indicates a communication issue with an essential safety system like the brake system control module. It's best to have the vehicle inspected and repaired as soon as possible.

6. How can I repair the U0129 code on my Toyota RAV4?

Repairing the U0129 code may involve replacing the brake system control module if it is determined to be faulty. Additionally, repairing any damaged wiring or connectors and ensuring proper communication network functionality may resolve the issue.

7. Can I reset the U0129 code on my Toyota RAV4 with a simple DIY method?

Resetting the U0129 code may be possible by using an OBDII scanner to clear the code. However, it is essential to address the underlying cause of the code to prevent it from reoccurring.

8. Are there any common mistakes to avoid when dealing with the U0129 code on a Toyota RAV4?

When dealing with the U0129 code, avoid overlooking the brake system control module as a potential cause of the communication issue. It's crucial to perform a comprehensive diagnosis to pinpoint the exact problem accurately.

9. Is the U0129 code on a Toyota RAV4 a serious issue?

The U0129 code should be taken seriously as it relates to a communication problem with the vehicle's brake system control module. Ignoring this issue could potentially impact the safety and performance of the vehicle's braking system.

10. How much can I expect to pay to fix the U0129 code on my 2014 Toyota RAV4?

The cost of fixing the U0129 code on a Toyota RAV4 can vary depending on the underlying cause of the issue. Repair costs may include diagnostic fees, parts replacement, and labor costs, so it's advisable to consult a professional mechanic for an accurate estimate.