AutoCodes – Generic – U029B

U029B Code - Lost Communication With Drive Motor Control Module 'C'

Quick Answer

A Controller Area Network (CAN) is a vehicle bus standard designed to interconnect automotive devices without a host computer. Common causes include Faulty Drive Motor Control Module 'C', Drive Motor Control Module 'C' harness is open or shorted, Drive Motor Control Module 'C' 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: U029B indicates Lost Communication With Drive Motor Control Module 'C'.
Common causes: Common causes include Faulty Drive Motor Control Module 'C', Drive Motor Control Module 'C' harness is open or shorted, Drive Motor Control Module 'C' 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 2,231

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 Apr 06, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code U029B Description

A Controller Area Network (CAN) is a vehicle bus standard designed to interconnect automotive devices without a host computer. Operating information and commands are exchanged among the devices. The devices have programmed information about what messages are needed to be exchanged on the serial data circuits. CAN bus uses two dedicated wires for communication. The wires are called CAN high and CAN low. When the CAN bus is in idle mode, both lines carry 2.5V. When data bits are being transmitted, the CAN high line goes to 3.75V, and the CAN low drops to 1.25V, thereby generating 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 Drive Motor Control Module 'C' has not been received.

OBDII Code U029B - Lost Communication With Drive Motor Control Module 'C' - AutoCodes.com — U029B Code - Lost Communication With Drive Motor Control Module 'C'

What does this mean?

What are the Possible Causes of the DTC U029B?

Faulty Drive Motor Control Module 'C'
Drive Motor Control Module 'C' harness is open or shorted
Drive Motor Control Module 'C' circuit poor electrical connection

How to Fix the DTC U029B?

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 U029B 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 U029B Code

1. What are common symptoms of OBDII code U029B?

- Common symptoms include the check engine light illuminating, loss of power, and potential issues with the vehicle's drivability.

2. What could cause the OBDII code U029B to appear?

- The code may be triggered by a faulty drive motor control module 'C', wiring issues, or communication problems between modules.

3. How can I diagnose the cause of OBDII code U029B?

- A thorough diagnostic scan using an OBDII scanner can help identify the specific issue causing the code, such as checking for communication errors or module malfunctions.

4. Is it safe to continue driving with OBDII code U029B present?

- It is recommended to address the issue promptly to prevent further damage to the vehicle and ensure optimal performance.

5. What are some repair tips for fixing OBDII code U029B?

- Repair tips may include checking and repairing any damaged wiring, inspecting and replacing the drive motor control module 'C' if necessary, and resetting the fault codes.

6. Can a DIY enthusiast fix OBDII code U029B at home?

- While some individuals with mechanical knowledge may attempt to address the issue themselves, it is recommended to consult a professional mechanic for accurate diagnosis and repair.

7. How much does it typically cost to repair OBDII code U029B?

- The cost of repairs can vary depending on the specific cause of the issue, the extent of the damage, and labor rates in your area. It's best to obtain quotes from local repair shops.

8. Will resetting the OBDII code U029B make it go away permanently?

- Resetting the code may temporarily turn off the check engine light, but if the underlying issue is not resolved, the code is likely to reappear.

9. Can extreme weather conditions trigger OBDII code U029B?

- Extreme weather conditions can potentially affect the electrical components of the vehicle, leading to communication errors and triggering the code.

10. Is there a way to prevent OBDII code U029B from occurring in the future?

- Regular maintenance, timely repairs, and addressing any electrical issues promptly can help prevent the recurrence of OBDII code U029B.