AutoCodes – GMC – U189A GMC

U189A GMC Code - DC To DC Converter Control Module 'A' Lost Communication With Hybrid Powertrain Control Module

Quick Answer

Modules connected to the class 2 and high-speed General Motor Local Area Network (GMLAN) serial data circuits monitor for serial data communications during normal vehicle operation. Common causes include Faulty Hybrid Powertrain Control Module, Hybrid Powertrain Control Module harness is open or shorted, Hybrid Powertrain 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: U189A GMC indicates DC To DC Converter Control Module 'A' Lost Communication With Hybrid Powertrain Control Module.
Common causes: Common causes include Faulty Hybrid Powertrain Control Module, Hybrid Powertrain Control Module harness is open or shorted, Hybrid Powertrain 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 611

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

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Table of contents Created and updated by William Orellana on Jun 09, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code U189A GMC Description

Modules connected to the class 2 and 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 Diagnostic Trouble Code (DTC) is reported on a class 2 link to the scan tool by Powertrain Control Module (PCM) even if they may be set by different modules. The DTC will set when a node alive message has not been received from an identified module within the last 5 seconds after establishing class 2 serial data communication, or a supervised high-speed GMLAN message has not been received.

OBDII Code U189A GMC - DC To DC Converter Control Module 'A' Lost Communication With Hybrid Powertrain Control Module - AutoCodes.com — U189A GMC Code - DC To DC Converter Control Module 'A' Lost Communication With Hybrid Powertrain Control Module

What does this mean?

What are the Possible Causes of the DTC U189A GMC?

Faulty Hybrid Powertrain Control Module
Hybrid Powertrain Control Module harness is open or shorted
Hybrid Powertrain Control Module circuit poor electrical connection
Faulty DC To DC Converter Control Module 'A'

How to Fix the DTC U189A 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 U189A 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 U189A GMC Code

1. What are the common symptoms of OBDII code U189A in a GMC vehicle?

- Common symptoms include loss of power, poor fuel efficiency, warning lights on the dashboard, and difficulty starting the vehicle.

2. What causes the OBDII code U189A in a GMC vehicle?

- The code U189A is typically caused by a communication error between the DC To DC Converter Control Module and the Hybrid Powertrain Control Module.

3. How can I diagnose the OBDII code U189A in my GMC vehicle?

- Diagnosis usually involves using a diagnostic scanner to retrieve the code, checking for any related codes, and inspecting the wiring and connectors between the modules.

4. Can I continue driving my GMC vehicle with the OBDII code U189A?

- It is not recommended to continue driving the vehicle with this code present, as it can lead to further damage and potential safety issues.

5. How can I repair the OBDII code U189A in my GMC vehicle?

- Repair options may include checking and repairing any damaged wiring, replacing faulty modules, updating software, or reprogramming the modules.

6. Is it safe to clear the OBDII code U189A using a diagnostic scanner?

- Clearing the code temporarily may turn off the warning lights, but it is important to address the root cause of the issue to prevent it from recurring.

7. How much does it typically cost to repair the OBDII code U189A in a GMC vehicle?

- The cost of repairs can vary depending on the extent of the issue, the need for parts replacement, and labor charges. It is recommended to consult with a professional mechanic for an accurate estimate.

8. How long does it take to repair the OBDII code U189A in a GMC vehicle?

- The repair time can vary based on the specific diagnosis and required repairs. Some cases may be resolved quickly, while others may take more time for thorough troubleshooting and repair.

9. Can a DIY enthusiast fix the OBDII code U189A issue in a GMC vehicle?

- While some basic troubleshooting steps can be performed by DIY enthusiasts, diagnosing and repairing communication issues between control modules often require specialized tools and expertise best handled by a professional mechanic.

10. Are there any preventive maintenance tips to avoid encountering the OBDII code U189A in a GMC vehicle?

- Regular maintenance, such as checking the vehicle's electrical system, keeping connectors clean and secure, and addressing any warning lights promptly, can help prevent communication errors that lead to the U189A code.