AutoCodes – Toyota – U0129 2016 Toyota RAV4

U0129 2016 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 2016 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 553

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 2016 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 2016 Toyota RAV4 - Lost Communication with Brake System Control Module - AutoCodes.com — U0129 2016 Toyota RAV4 Code - Lost Communication with Brake System Control Module

What does this mean?

What are the Possible Causes of the DTC U0129 2016 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 2016 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 2016 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 2016 Toyota RAV4 Code

1. What are the common symptoms of OBDII code U0129 in a 2016 Toyota RAV4?

- Common symptoms include the ABS warning light or traction control light illuminating on the dashboard, loss of communication with the brake system control module, and potential issues with ABS functionality.

2. What can cause the OBDII code U0129 in a 2016 Toyota RAV4?

- The code U0129 typically indicates a communication problem between the vehicle's onboard computer system and the brake system control module. This can be caused by damaged wiring, a faulty control module, or a poor connection.

3. How can I diagnose the issue related to OBDII code U0129 in my 2016 Toyota RAV4?

- Diagnosing the issue involves checking the wiring connections between the control modules, inspecting for any visible damage, and using a diagnostic scanner to communicate with the affected modules for further testing.

4. Can driving with the OBDII code U0129 present cause any safety concerns?

- Driving with the U0129 code may lead to potential safety risks as it affects the communication with the brake system control module, impacting the vehicle's ABS functionality and traction control systems.

5. What are some repair tips for fixing the U0129 code in a 2016 Toyota RAV4?

- Repair tips include checking and repairing any damaged wiring, ensuring proper connections between control modules, resetting the codes after repairs, and conducting a thorough test drive to confirm the issue is resolved.

6. Is it possible to clear the U0129 code in a 2016 Toyota RAV4 without addressing the underlying issue?

- While clearing the code may temporarily turn off the warning lights, the underlying communication issue with the brake system control module will persist, potentially leading to safety concerns and further system malfunctions.

7. How much does it typically cost to repair the U0129 code in a 2016 Toyota RAV4?

- Repair costs for the U0129 code can vary depending on the root cause of the communication problem. Costs may include labor charges for diagnosis and repair, replacement parts, and any additional programming or calibration needed.

8. Can a DIY enthusiast attempt to fix the U0129 code issue in a 2016 Toyota RAV4?

- While some basic troubleshooting like checking connections and inspecting wiring can be done by DIY enthusiasts, diagnosing and repairing the U0129 code may require specialized tools and expertise best handled by a professional technician.

9. Will the U0129 code in a 2016 Toyota RAV4 cause the vehicle to fail an emissions test?

- The U0129 code is related to a communication issue with the brake system control module and is not directly linked to emissions. However, unresolved issues affecting vehicle systems may contribute to a failed emissions test.

10. How soon should I address the U0129 code in my 2016 Toyota RAV4 to prevent further damage?

- It is recommended to address the U0129 code promptly to prevent potential safety risks and further damage to the vehicle's brake system control module. Delaying repairs may lead to more extensive issues and higher repair costs.