AutoCodes – GMC – U1111 GMC

U1111 GMC Code - Lost Communication With Chime Module

Quick Answer

Modules connected to the class 2 serial data circuit monitor for serial data communications during normal vehicle operation. Common causes include Faulty Chime Module, Chime Module harness is open or shorted, Chime 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: U1111 GMC indicates Lost Communication With Chime Module.
Common causes: Common causes include Faulty Chime Module, Chime Module harness is open or shorted, Chime 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 637

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 24, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code U1111 GMC Description

Modules connected to the class 2 serial data circuit monitor for serial data communications during normal vehicle operation. Operating information and commands are exchanged among the modules. When a module receives a message for a critical operating parameter, the module records the identification number of the module which sent the message for the state of health monitoring/node alive messages. A critical operating parameter is one which, when not received, requires that the module use a default value for that parameter. Once an identification number is learned by a module, it will monitor for that module node alive message. Each module on the class 2 serial data circuit is required to send a Node Alive message every 2 seconds. When no message is detected from a learned identification number for 5 seconds, a Diagnostic Trouble Code (DTC) U1111 is set.

OBDII Code U1111 GMC - Lost Communication With Chime Module - AutoCodes.com — U1111 GMC Code - Lost Communication With Chime Module

What does this mean?

What are the Possible Causes of the DTC U1111 GMC?

Faulty Chime Module
Chime Module harness is open or shorted
Chime Module circuit poor electrical connection

How to Fix the DTC U1111 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 U1111 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 U1111 GMC Code

1. What are the common symptoms of OBDII code U1111 GMC (Lost Communication With Chime Module)?

- Common symptoms include a malfunctioning chime system, loss of audible alerts, and potential issues with other vehicle modules.

2. What are the possible causes of U1111 GMC code?

- The code U1111 indicates a communication problem between the vehicle's onboard diagnostic system and the chime module. Possible causes include wiring issues, a faulty chime module, or a malfunction in the vehicle's network communication system.

3. How can I diagnose the U1111 GMC code?

- To diagnose the U1111 code, start by checking the wiring connections to the chime module. Inspect for any visible damage or loose connections. You may also need to use a diagnostic scanner to read the codes and perform further troubleshooting.

4. Can I continue driving with the U1111 code present?

- While the U1111 code may not affect the drivability of the vehicle, it is important to address the underlying communication issue as it may lead to other problems with the vehicle's electrical system.

5. How can I repair the U1111 GMC code?

- Repairing the U1111 code typically involves fixing the communication problem between the vehicle's diagnostic system and the chime module. This may include repairing damaged wiring, replacing the chime module, or reprogramming the vehicle's computer system.

6. Is it safe to ignore the U1111 code?

- Ignoring the U1111 code may result in the loss of important alerts and notifications while driving. It is recommended to address the issue promptly to ensure the overall safety and functionality of the vehicle's electrical system.

7. Can a DIY enthusiast fix the U1111 code?

- Depending on your skill level and access to tools, you may be able to diagnose and repair the U1111 code yourself. However, if you are unsure or inexperienced with automotive electrical systems, it is best to seek professional help.

8. How much does it cost to repair the U1111 GMC code?

- The cost of repairing the U1111 code can vary depending on the underlying cause of the communication issue. It may range from a simple fix like repairing wiring to a more complex repair involving module replacement.

9. Will resetting the code make it go away permanently?

- Resetting the U1111 code may temporarily clear the warning light, but if the root cause of the communication problem is not addressed, the code is likely to reappear. It's important to diagnose and fix the issue to prevent recurring problems.

10. Can the U1111 GMC code affect other vehicle systems?

- Yes, the U1111 code indicates a communication problem within the vehicle's network system, which can potentially impact the functionality of other modules and systems that rely on the chime module for communication.