AutoCodes – GMC – U186B GMC

U186B GMC Code - Electronic Brake Control Module Lost Communication With Transmission Control Module

Quick Answer

Modules connected to the Controller Area Network (CAN) serial data circuits monitor for serial data communications during normal vehicle operation. Common causes include Faulty Transmission Control Module (TCM), Transmission Control Module harness is open or shorted, Transmission Control Module 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: U186B GMC indicates Electronic Brake Control Module Lost Communication With Transmission Control Module.
Common causes: Common causes include Faulty Transmission Control Module (TCM), Transmission Control Module harness is open or shorted, Transmission Control Module 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 853

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 Jun 08, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code U186B GMC Description

Modules connected to the Controller Area Network (CAN) serial data circuits monitor for serial data communications during normal vehicle operation. Operating information and commands are exchanged among the modules. The modules have prerecorded information about what messages are needed to be exchanged on the serial data circuits. The messages are supervised and also, some periodic messages are used by the receiver module as an availability indication of the transmitter module. Each message contains the identification number of the transmitter module. A module with a CAN serial data circuits malfunction or which loses power during the current ignition cycle will have a Loss of Communication Diagnostic Trouble Code (DTC) set by other modules that depend on information from that failed module. If any of the CAN circuit are shorted to battery voltage, ground, or between them no communication is possible on the CAN serial data bus, a Diagnostic Trouble Code will set.

OBDII Code U186B GMC - Electronic Brake Control Module Lost Communication With Transmission Control Module - AutoCodes.com — U186B GMC Code - Electronic Brake Control Module Lost Communication With Transmission Control Module

What does this mean?

What are the Possible Causes of the DTC U186B GMC?

Faulty Transmission Control Module (TCM)
Transmission Control Module harness is open or shorted
Transmission Control Module circuit poor electrical connection

How to Fix the DTC U186B GMC?

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 U186B GMC 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 U186B GMC Code

1. What are the common symptoms of OBDII code U186B GMC?

The common symptoms of code U186B GMC include issues with the electronic brake control system, transmission shifting problems, and dashboard warning lights related to the brake or transmission system.

2. What are the potential causes of code U186B GMC?

The code U186B GMC is typically triggered when there is a communication error between the electronic brake control module and the transmission control module. This can be caused by wiring issues, faulty modules, or software malfunctions.

3. How can I diagnose OBDII code U186B GMC?

Diagnosing code U186B GMC usually involves using a diagnostic scanner to retrieve the trouble codes, checking the wiring connections between the brake control module and transmission control module, and performing a thorough inspection of the modules themselves.

4. Can I still drive my vehicle with code U186B GMC?

It is not recommended to drive your vehicle with code U186B GMC present, as it can lead to unsafe driving conditions due to potential issues with the electronic brake control system and transmission communication.

5. How do I repair OBDII code U186B GMC?

Repairing code U186B GMC may involve checking and repairing any damaged wiring, replacing faulty modules, and ensuring that the communication between the brake control module and transmission control module is functioning properly.

6. Are there any DIY tips for fixing code U186B GMC?

While diagnosing and repairing code U186B GMC may require specialized tools and expertise, you can start by checking the wiring connections for any visible damage and ensuring that all connectors are securely plugged in.

7. Can a software update resolve OBDII code U186B GMC?

In some cases, a software update provided by the manufacturer may resolve code U186B GMC if the issue is related to software malfunctions. It is recommended to consult with a professional technician for guidance on software updates.

8. How much does it cost to fix OBDII code U186B GMC?

The cost of fixing code U186B GMC can vary depending on the underlying cause of the issue, the extent of repairs needed, and labor costs. It is advisable to obtain quotes from automotive repair shops for an accurate estimate.

9. Will resetting the trouble codes clear OBDII code U186B GMC?

Resetting the trouble codes may temporarily clear code U186B GMC, but if the underlying issue is not addressed, the code is likely to reappear. It is essential to diagnose and repair the root cause of the problem to prevent recurrence.

10. Is OBDII code U186B GMC a serious issue?

Code U186B GMC should be taken seriously as it indicates a communication error between critical control modules in the vehicle. Ignoring this code can lead to safety risks and potential damage to the electronic brake control and transmission systems.