AutoCodes – Cadillac – U1838 Cadillac

U1838 Cadillac 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 Cadillac 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.

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Code Popularity 478

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

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 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 U1838 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.

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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 U1838 Cadillac Code

1. What does the OBDII code U1838 mean on a Cadillac?

The U1838 code means there is a lost communication issue with the Battery Charger Control Module on the High Voltage Energy Management CAN bus.

2. What are the common symptoms of the U1838 code in a Cadillac?

Symptoms may include the check engine light being illuminated, charging system malfunctions, reduced or no electric vehicle operation, and possible warning messages on the dashboard.

3. What causes the U1838 code in a Cadillac?

Common causes include a faulty Battery Charger Control Module, damaged or corroded wiring or connectors in the CAN bus, a software glitch, or a blown fuse related to the charging system.

4. Can the U1838 code cause the vehicle to stop working?

Yes, this code can lead to reduced functionality or even a failure of the high-voltage charging system, impacting the vehicle's drivability.

5. How do you diagnose the U1838 code in a Cadillac?

Diagnosis involves scanning the vehicle with an OBDII scanner, inspecting the wiring and connectors for damage or corrosion, checking for blown fuses, and testing the Battery Charger Control Module.

6. Can you drive a Cadillac with the U1838 code?

Itâ€™s not recommended to drive the vehicle with this code since it could lead to further damage or leave you stranded if the charging system fails entirely.

7. How is the U1838 code fixed in a Cadillac?

Repairs typically involve replacing or repairing damaged wiring, cleaning corroded connectors, updating module software, or replacing the Battery Charger Control Module if itâ€™s defective.

8. Is the U1838 code exclusive to Cadillac electric or hybrid vehicles?

Yes, this code is specific to Cadillac vehicles equipped with high-voltage energy management systems, such as hybrids or electric models.

9. Can a software update fix the U1838 code on a Cadillac?

In some cases, a software update to the Battery Charger Control Module or related systems can resolve communication issues and clear the code.

10. How much does it cost to fix the U1838 code on a Cadillac?

Repair costs vary depending on the issue, but they can range from $100 for minor wiring repairs to over $1,000 if the Battery Charger Control Module needs replacement.