AutoCodes – Cadillac – U1879 Cadillac

U1879 Cadillac 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 Cadillac 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 570

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

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 Cadillac?

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 Cadillac 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 Cadillac code?

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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 Cadillac Code

1. What are the common symptoms of OBDII code U1879 in a Cadillac related to Drive Motor Control Module 2 Lost Communication With Engine Control Module?

- Common symptoms include engine misfires, reduced engine performance, illuminated Check Engine light, and difficulty starting the vehicle.

2. What are the possible causes of OBDII code U1879 in a Cadillac?

- Possible causes include faulty wiring or connections between the Drive Motor Control Module 2 and the Engine Control Module, a malfunctioning control module, or software issues.

3. How can I diagnose OBDII code U1879 in my Cadillac?

- Diagnosis typically involves using an OBDII scanner to retrieve the specific error code, checking for any related codes or pending codes, and conducting a thorough inspection of the wiring and connections between the affected modules.

4. What are some repair tips for addressing OBDII code U1879 in a Cadillac?

- Repair tips may include checking and repairing any damaged wiring or loose connections, resetting the control modules, updating software if necessary, and conducting a thorough system reset.

5. Can I drive my Cadillac with OBDII code U1879 present?

- It is not recommended to drive your Cadillac with this code present, as it can lead to further damage to the vehicle and potentially unsafe driving conditions.

6. How much does it typically cost to repair OBDII code U1879 in a Cadillac?

- The cost of repair can vary depending on the specific underlying issue causing the code. It is recommended to consult a professional mechanic for an accurate diagnosis and cost estimate.

7. Is it possible to clear OBDII code U1879 in a Cadillac without fixing the underlying issue?

- Clearing the code without addressing the underlying problem may temporarily turn off the Check Engine light, but the issue will likely reoccur, leading to potential long-term damage.

8. Can a DIY enthusiast fix OBDII code U1879 in a Cadillac?

- While some basic troubleshooting steps can be performed by a DIY enthusiast, diagnosing and repairing this code often requires specialized tools and expertise, so it is advisable to seek professional help.

9. How long does it typically take to repair OBDII code U1879 in a Cadillac?

- The repair time can vary depending on the exact cause of the code and the extent of the repairs needed. It is best to consult a mechanic for a more accurate estimate of the repair duration.

10. Are there any preventive measures to avoid OBDII code U1879 in a Cadillac?

- Regular vehicle maintenance, including checking and cleaning electrical connections, can help prevent issues that may lead to OBDII code U1879. Regularly scanning for codes and addressing them promptly can also help prevent more serious problems.