AutoCodes – GMC – U012A GMC

U012A GMC Code - Lost Communication With Chassis 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 Chassis Control Module, Chassis Control Module harness is open or shorted, Chassis 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: U012A GMC indicates Lost Communication With Chassis Control Module.
Common causes: Common causes include Faulty Chassis Control Module, Chassis Control Module harness is open or shorted, Chassis 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 3,138

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 01, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code U012A GMC 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 are needed 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) sets when a periodic message from the Chassis Control Module has not been received.

OBDII Code U012A GMC - Lost Communication With Chassis Control Module - AutoCodes.com — U012A GMC Code - Lost Communication With Chassis Control Module

What does this mean?

What are the Possible Causes of the DTC U012A GMC?

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

How to Fix the DTC U012A 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 U012A 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 U012A GMC Code

1. What are common symptoms of the U012A GMC OBDII code?

- Common symptoms include issues with the stability control system, traction control system, and ABS system. The dashboard may display warning lights related to these systems.

2. What does the U012A GMC code "Lost Communication With Chassis Control Module" mean?

- This code indicates a communication problem between the vehicle's main computer system and the chassis control module, which manages various safety systems.

3. What are possible causes of the U012A GMC code?

- Possible causes include faulty wiring connections, damaged wiring harnesses, a malfunctioning chassis control module, or issues with the vehicle's main computer system.

4. How can I diagnose the U012A GMC code?

- Diagnosis typically involves conducting a thorough inspection of the wiring connections, checking for damaged wires or connectors, and using a diagnostic scanner to communicate with the chassis control module.

5. Can I still drive my vehicle with the U012A GMC code present?

- It is not recommended to continue driving the vehicle with the U012A code present, as it may affect the proper functioning of safety systems like ABS and traction control.

6. How can I repair the U012A GMC code?

- Repair options include checking and repairing any damaged wiring, replacing the chassis control module if necessary, and ensuring all connections are secure and free of corrosion.

7. Is it safe to clear the U012A GMC code without addressing the underlying issue?

- Clearing the code without addressing the underlying communication issue may temporarily turn off warning lights, but it will not resolve the potential safety concerns associated with malfunctioning safety systems.

8. Can a DIY enthusiast fix the U012A GMC code issue?

- Some aspects of diagnosing and repairing the U012A code may be within reach of experienced DIY enthusiasts, but dealing with complex wiring and electronic systems may require professional expertise.

9. How much does it cost to repair the U012A GMC code?

- The cost of repairing the U012A code can vary depending on the specific issue causing the communication fault. Costs may include parts, labor, and diagnostic fees.

10. Will the U012A GMC code affect my vehicle's performance?

- While the U012A code itself may not directly impact performance, it can lead to safety system malfunctions that could affect overall vehicle handling and safety.