AutoCodes – GMC – C0291 GMC

C0291 GMC Code - Lost Communications With BCM

Quick Answer

The Body Control Module (BCM) sends a state of health serial data message to the Electronic Brake Control Module (EBCM) within 5.5 seconds after the ignition is turned ON. Common causes include Faulty Electronic Brake Control Module (EBCM), Electronic Brake Control Module (EBCM) harness is open or shorted, Electronic Brake Control Module (EBCM) 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: C0291 GMC indicates Lost Communications With BCM.
Common causes: Common causes include Faulty Electronic Brake Control Module (EBCM), Electronic Brake Control Module (EBCM) harness is open or shorted, Electronic Brake Control Module (EBCM) 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 5,688

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 18, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code C0291 GMC Description

The Body Control Module (BCM) sends a state of health serial data message to the Electronic Brake Control Module (EBCM) within 5.5 seconds after the ignition is turned ON. The EBCM fails to receive serial data from the BCM.

OBDII Code C0291 GMC - Lost Communications With BCM - AutoCodes.com — C0291 GMC Code - Lost Communications With BCM

What does this mean?

What are the Possible Causes of the DTC C0291 GMC?

Faulty Electronic Brake Control Module (EBCM)
Electronic Brake Control Module (EBCM) harness is open or shorted
Electronic Brake Control Module (EBCM) circuit poor electrical connection

How to Fix the DTC C0291 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 C0291 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 C0291 GMC Code

1. What are the common symptoms of OBDII code C0291 "Lost Communications With BCM" in a GMC vehicle?

- Common symptoms include malfunctioning power windows, door locks, and lighting systems, as well as intermittent issues with the vehicle's security system.

2. What are some possible causes of OBDII code C0291 in a GMC vehicle?

- The code C0291 can be triggered by a faulty Body Control Module (BCM), damaged wiring or connectors, a blown fuse, or a software issue within the BCM.

3. How can I diagnose the cause of OBDII code C0291 in my GMC vehicle?

- To diagnose the issue, you can start by checking the BCM for any visible damage or loose connections. It's also recommended to perform a thorough inspection of the wiring harness and connectors for any signs of wear or corrosion.

4. Can I still drive my GMC vehicle with OBDII code C0291 present?

- While it may be possible to drive the vehicle with the code present, it's not recommended as certain crucial systems controlled by the BCM may not function properly. It's advised to address the issue promptly.

5. How can I repair OBDII code C0291 in my GMC vehicle?

- Repairing the code C0291 typically involves either repairing or replacing the faulty BCM, addressing any wiring issues, or resetting the BCM software using a diagnostic scanner.

6. Will disconnecting the battery reset OBDII code C0291 in my GMC vehicle?

- Disconnecting the battery may temporarily clear the code, but it's not a reliable long-term solution. It's best to diagnose the root cause of the issue and address it directly.

7. Is it possible to reset OBDII code C0291 in my GMC vehicle without a diagnostic scanner?

- While disconnecting the battery may clear the code temporarily, using a diagnostic scanner is the most effective way to reset the code and ensure the underlying issue is properly diagnosed and addressed.

8. Are there any common mistakes to avoid when dealing with OBDII code C0291 in a GMC vehicle?

- One common mistake is overlooking simple wiring or connector issues that could be causing the communication loss with the BCM. It's important to conduct a thorough inspection before replacing any major components.

9. Can extreme weather conditions cause OBDII code C0291 to trigger in a GMC vehicle?

- Yes, extreme temperatures or moisture exposure can sometimes lead to electrical issues that trigger the code C0291. It's essential to keep the vehicle's electrical components well-protected.

10. How can I prevent OBDII code C0291 from occurring in my GMC vehicle in the future?

- To prevent the code from occurring again, it's crucial to ensure regular maintenance of the vehicle's electrical system, including checking and cleaning connectors, securing wiring harnesses, and protecting the BCM from environmental factors.