U1879 GMC 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 GMC 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.
Code U1879 GMC Description
What are the Possible Causes of the DTC U1879 GMC?
- 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 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 U1879 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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Frequently Asked Questions about U1879 GMC Code
1. What does OBDII code U1879 mean on a GMC?
U1879 indicates that the Drive Motor Control Module 2 has lost communication with the Engine Control Module (ECM), typically in hybrid or electric vehicles.
2. What are the common symptoms of code U1879 on a GMC?
Symptoms may include reduced engine or motor performance, warning lights such as the check engine light or hybrid system light, and potential loss of regenerative braking.
3. What causes U1879 to appear on a GMC vehicle?
This code is usually caused by issues such as a faulty drive motor control module, a failing engine control module, damaged wiring or connectors in the communication circuit, or software glitches.
4. Can driving with a U1879 code damage my GMC?
It depends on the severity of the communication failure. In some cases, it may lead to limited drivability or reduced performance, so it’s best to address the issue promptly.
5. How do I diagnose a U1879 code on a GMC?
Start by inspecting the wiring and connectors between the Drive Motor Control Module 2 and the ECM. Use a scan tool to check for additional codes and verify the communication status of the modules.
6. Can a software update fix the U1879 code?
Yes, if the issue is related to a software glitch, updating the ECM or Drive Motor Control Module software through the dealership may resolve the problem.
7. Do I need to replace the Drive Motor Control Module for a U1879 code?
Not necessarily. Replacement should only be considered after verifying that the module itself is faulty and other potential causes, such as wiring or software, have been ruled out.
8. How much does it cost to repair a U1879 code on a GMC?
Repair costs vary depending on the cause. Simple wiring repairs may be inexpensive, while module replacements or reprogramming can cost several hundred dollars.
9. Can a weak battery cause the U1879 code on a hybrid or electric GMC?
Yes, a weak 12V auxiliary battery or high-voltage battery issue can disrupt communication between modules, potentially triggering this code.
10. Is U1879 a common issue in GMC vehicles?
This code is less common and typically appears in GMC hybrid or electric vehicles, where multiple control modules must communicate seamlessly.
Discuss the causes and fixes for U1879 GMC OBDII Code
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