AutoCodes – Generic – U1879

U1879 Code - Drive Motor Control Module 2 Lost Communication With Engine Control Module

Quick Answer

Devices connected to the serial data circuits monitor for serial data communications during normal vehicle operation. Common causes include Faulty Engine Control Module (ECM), Engine Control Module harness is open or shorted, Engine 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: U1879 indicates Drive Motor Control Module 2 Lost Communication With Engine Control Module.
Common causes: Common causes include Faulty Engine Control Module (ECM), Engine Control Module harness is open or shorted, Engine 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 1,452

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 U1879 Description

Devices connected to the serial data circuits monitor for serial data communications during normal vehicle operation. Operating information and commands are exchanged among the devices. The devices 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 device as an availability indication of the transmitter device. Each message contains the identification number of the transmitter device. The Diagnostic Trouble Code (DTC) will set if a supervised periodic message that includes the transmitter device availability has not been received.

OBDII Code U1879 - Drive Motor Control Module 2 Lost Communication With Engine Control Module - AutoCodes.com — U1879 Code - Drive Motor Control Module 2 Lost Communication With Engine Control Module

What does this mean?

What are the Possible Causes of the DTC U1879?

Faulty Engine Control Module (ECM)
Engine Control Module harness is open or shorted
Engine Control Module circuit poor electrical connection

How to Fix the DTC U1879?

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 U1879 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.

Need more information about the U1879 code?

Need more information on how to fix the U1879 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the U1879 code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

U1879 Buick — Drive Motor Control Module 2 Lost Communication With Engine Control Module
U1879 Cadillac — Drive Motor Control Module 2 Lost Communication With Engine Control Module
U1879 Chevrolet — Drive Motor Control Module 2 Lost Communication With Engine Control Module
U1879 GMC — Drive Motor Control Module 2 Lost Communication With Engine Control Module

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 U1879 Code

1. What are common symptoms of OBDII code U1879?

- Common symptoms include the Check Engine Light (CEL) illuminating, loss of power, rough running engine, and potential issues with vehicle performance.

2. What can cause OBDII code U1879 to trigger?

- This code can be triggered by a communication breakdown between the Drive Motor Control Module 2 and the Engine Control Module, which may be caused by wiring issues, faulty modules, or software glitches.

3. How do I diagnose the cause of U1879 code?

- Diagnosis typically involves checking the wiring connections between the modules, testing the modules for functionality, and using a diagnostic scanner to retrieve additional fault codes and data.

4. Can I still drive my vehicle with code U1879 present?

- It is not recommended to drive your vehicle with this code present, as it may lead to further issues with engine control and performance.

5. How can I repair OBDII code U1879?

- Repairing this code often involves fixing any wiring issues, replacing faulty modules, updating software as needed, and clearing the code with a diagnostic scanner.

6. Is it possible to prevent code U1879 from recurring?

- Regular maintenance, checking and maintaining wiring connections, and addressing any related issues promptly can help prevent the recurrence of this code.

7. Can a DIY enthusiast fix OBDII code U1879 at home?

- Depending on your mechanical skills and access to tools, you may be able to address some aspects of this code at home. However, more complex issues may require professional help.

8. Are there any safety concerns associated with code U1879?

- While this code itself may not pose immediate safety risks, driving with unresolved communication issues between critical control modules can potentially lead to unsafe driving conditions.

9. Is it necessary to reset the code after repairs are made?

- Yes, it is important to clear the code after repairs are made to ensure that the issue has been resolved and to prevent further confusion during future diagnostics.

10. How much does it typically cost to fix OBDII code U1879?

- The cost of repairs for this code can vary depending on the underlying cause, parts needed, and labor charges. It is recommended to obtain quotes from different repair shops for accurate pricing.