AutoCodes – Buick – U1879 Buick

U1879 Buick 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 Buick 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 419

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 Buick 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 Buick - Drive Motor Control Module 2 Lost Communication With Engine Control Module - AutoCodes.com — U1879 Buick 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 Buick?

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 Buick?

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 Buick 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 U1879 Buick Code

1. What does the OBDII code U1879 mean on a Buick?

U1879 indicates that the Drive Motor Control Module 2 has lost communication with the Engine Control Module.

2. What are the common symptoms of code U1879 in a Buick?

Symptoms may include reduced engine performance, warning lights on the dashboard (such as the check engine light), and potential drivability issues like hesitation or stalling.

3. What causes the U1879 code to appear in a Buick?

The code can be triggered by faulty wiring or connectors, a malfunctioning Drive Motor Control Module 2 or Engine Control Module, software issues, or electrical interference.

4. Can I drive my Buick with the U1879 code active?

Driving with this code is not recommended, as it may lead to reduced performance or further damage to the vehicle's control modules.

5. How do I diagnose the U1879 code in a Buick?

Start by inspecting wiring and connectors for damage or looseness, perform a scan tool diagnostic to check for related codes, and test communication between the modules.

6. What tools are needed to troubleshoot the U1879 code?

A professional-grade OBDII scanner with bidirectional capabilities and a multimeter are essential tools for diagnosing this communication issue.

7. Can the U1879 code be caused by a software issue?

Yes, outdated or corrupted software in the Drive Motor Control Module or Engine Control Module can cause a loss of communication and trigger this code.

8. What repairs might fix the U1879 code in a Buick?

Repairs could include fixing or replacing damaged wiring, cleaning or reconnecting loose connectors, updating module software, or replacing the faulty control module.

9. How much does it cost to fix the U1879 code in a Buick?

The cost varies based on the issue, ranging from $50â€“$100 for minor wiring repairs to $500 or more for module replacement and reprogramming.

10. Can a bad battery cause the U1879 code?

Yes, a weak or failing battery can cause voltage irregularities that disrupt communication between the Drive Motor Control Module 2 and the Engine Control Module.