AutoCodes – GMC – U1838 GMC

U1838 GMC Code - Lost Communication With Battery Charger Control Module On High Voltage Energy Management CAN Bus

Quick Answer

The serial data circuit is the means by which the devices in the vehicle communicate with each other. Common causes include Faulty Battery Charger Control Module, Battery Charger Control Module harness is open or shorted, Battery Charger 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: U1838 GMC indicates Lost Communication With Battery Charger Control Module On High Voltage Energy Management CAN Bus.
Common causes: Common causes include Faulty Battery Charger Control Module, Battery Charger Control Module harness is open or shorted, Battery Charger 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.

Save to My Repairs My Repairs

AI answers can be wrong. Verify repairs with testing. Open full chat

Code Popularity 568

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 07, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
Add Comment

💬 Need more help? Ask Coddy for instant answers — it's free!

Code U1838 GMC Description

The serial data circuit is the means by which the devices in the vehicle communicate with each other. Once the scan tool is connected to the serial data circuit through the Data Link Connector (DLC), the scan tool can be used to monitor each device for diagnostic purposes and to check for Diagnostic Trouble Code (DTC). When the vehicle is ON, each device communicating on the serial data circuit sends a state of health message to ensure that the device is operating properly. When a device stops communicating on the serial data circuit, for example, if the device loses power or ground, the state of health message it normally sends on the serial data circuit disappears. Other devices on the serial data circuit, which expect to receive that state of the health message, detect its absence; those devices in turn set a DTC associated with the loss of the state of health of the non-communicating device. A loss of serial data communications DTC does not represent a failure of the devices that contain the stored DTC. The DTC will set when a supervised periodic message that includes the transmitter device availability has not been received.

OBDII Code U1838 GMC - Lost Communication With Battery Charger Control Module On High Voltage Energy Management CAN Bus - AutoCodes.com — U1838 GMC Code - Lost Communication With Battery Charger Control Module On High Voltage Energy Management CAN Bus

What does this mean?

What are the Possible Causes of the DTC U1838 GMC?

Faulty Battery Charger Control Module
Battery Charger Control Module harness is open or shorted
Battery Charger Control Module circuit poor electrical connection

How to Fix the DTC U1838 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 U1838 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.

Need more information about the U1838 GMC code?

Need more information on how to fix the U1838 GMC code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the U1838 GMC code diagnosed by a professional: Find a repair shop in your area

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 U1838 GMC Code

1. What are common symptoms of OBDII code U1838 in a GMC vehicle?

- Common symptoms include the check engine light illuminating, issues with the battery charging system, and potential loss of communication with the battery charger control module.

2. What are possible causes of the U1838 code in a GMC related to the battery charger control module?

- Possible causes may include a faulty battery charger control module, wiring issues, poor connections, or problems with the high voltage energy management CAN bus.

3. How can I diagnose the U1838 code in my GMC vehicle?

- Diagnosing the U1838 code usually involves using an OBDII scanner to retrieve the code and perform a thorough inspection of the battery charger control module, wiring, and connections for any visible damage or issues.

4. Can I still drive my GMC with the U1838 code present?

- It is not recommended to drive your GMC with the U1838 code present, as it can lead to potential issues with the battery charging system and other electrical components.

5. How can I repair the U1838 code in my GMC?

- Repairing the U1838 code often involves addressing the root cause, such as replacing a faulty battery charger control module, repairing damaged wiring or connections, and ensuring proper communication on the high voltage energy management CAN bus.

6. Are there any safety precautions to consider when working on the battery charger control module related to the U1838 code?

- Yes, it is important to disconnect the vehicle's battery and take necessary precautions when working on high voltage components to prevent electrical shock or damage.

7. Can a DIY enthusiast fix the U1838 code issue in a GMC?

- While some experienced DIY enthusiasts may be able to address the U1838 code by following proper diagnostic procedures and repair steps, it is recommended to consult a professional technician for accurate diagnosis and repair.

8. Will resetting the OBDII code by clearing it with a scanner fix the U1838 issue?

- Clearing the code with an OBDII scanner may temporarily remove the check engine light, but it will not resolve the underlying issue causing the U1838 code in the GMC.

9. What role does the battery charger control module play in a GMC's high voltage energy management system?

- The battery charger control module is responsible for managing the charging of the high voltage battery in hybrid or electric GMC vehicles, ensuring efficient energy utilization and system performance.

10. Is the U1838 OBDII code specific to GMC vehicles, or can it occur in other vehicle makes?

- While the U1838 code specifically references GMC vehicles in relation to the battery charger control module, similar communication issues with high voltage energy management systems can occur in other vehicle makes as well.