AutoCodes – Cadillac – U0137 Cadillac

U0137 Cadillac Code - Lost Communication with Trailer Brake Control Module

Quick Answer

Modules connected to the high-speed General Motor Local Area Network (GMLAN) serial data circuits monitor for serial data communications during normal vehicle operation. Common causes include Faulty Trailer Brake Control Module, Trailer Brake Control Module harness is open or shorted, Trailer Brake 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: U0137 Cadillac indicates Lost Communication with Trailer Brake Control Module.
Common causes: Common causes include Faulty Trailer Brake Control Module, Trailer Brake Control Module harness is open or shorted, Trailer Brake 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 599

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

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Table of contents Created and updated by William Orellana on Jul 21, 2023

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code U0137 Cadillac Description

Modules connected to the high-speed General Motor Local Area Network (GMLAN) 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 need to be exchanged on the serial data circuits, for each virtual network. The messages are supervised and also, some periodic messages are used by the receiver module as an availability indication of the transmitter module. The supervision time-out period is 250 ms. Each message contains the identification number of the transmitter module. The Diagnostic Trouble Code (DTC) will be set when the device setting the DTC has attempted to establish communications on the serial data circuits more than 3 times in 5 s.

OBDII Code U0137 Cadillac - Lost Communication with Trailer Brake Control Module - AutoCodes.com — U0137 Cadillac Code - Lost Communication with Trailer Brake Control Module

What does this mean?

What are the Possible Causes of the DTC U0137 Cadillac?

Faulty Trailer Brake Control Module
Trailer Brake Control Module harness is open or shorted
Trailer Brake Control Module circuit poor electrical connection

How to Fix the DTC U0137 Cadillac?

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 U0137 Cadillac 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 U0137 Cadillac Code

1. What does the OBDII code U0137 mean on a Cadillac?

U0137 indicates a loss of communication between the vehicle's main control modules and the Trailer Brake Control Module (TBCM).

2. What are the common symptoms of code U0137 on a Cadillac?

Symptoms may include the trailer brake system not functioning, warning lights on the dashboard, or an inability to detect the trailer.

3. What causes the U0137 code to appear on a Cadillac?

Common causes include damaged wiring, a faulty Trailer Brake Control Module, poor electrical connections, or issues with the CAN bus network.

4. Can I still drive my Cadillac with the U0137 code?

Yes, you can still drive the vehicle, but the trailer brake system may not work, which can be unsafe if towing a trailer.

5. How do I diagnose the U0137 code on my Cadillac?

Start by inspecting the wiring, connectors, and fuses for the TBCM. Use a scan tool to check for additional codes and test the CAN bus network for communication issues.

6. Is a faulty Trailer Brake Control Module the only cause of U0137?

No, other causes include damaged wiring, corroded connectors, or a malfunction in related control modules.

7. How much does it cost to repair the U0137 code on a Cadillac?

Repair costs vary but can range from $100 for simple wiring repairs to $500 or more if the TBCM needs replacement.

8. Can I fix the U0137 code on my Cadillac myself?

If youâ€™re experienced with electrical systems, you can inspect and repair wiring or connectors. However, module replacement or advanced diagnostics may require a professional.

9. Does clearing the U0137 code fix the problem?

Clearing the code resets the system temporarily, but the underlying issue must be resolved to prevent the code from returning.

10. What tools are needed to address the U0137 code on a Cadillac?

You'll need an OBDII scanner, a multimeter for electrical testing, and potentially a repair manual for wiring diagrams specific to your Cadillac model.