# Lost Communication with Battery Charger Control Module on High Voltage Energy Management Communication Bus

Source: https://obdlens.com/codes/u1838/
Last built: 7508d481ba6c398f25ed

[Diagnostic knowledge](https://obdlens.com/knowledge/) / U1838 — Lost Communication with Battery Charger Control Module on High Voltage Energy Management Communication Bus

U1838

U1838 is described as “Lost Communication with Battery Charger Control Module on High Voltage Energy Management Communication Bus” in the GM reference. 

Some scan tools (for example GM and Ford dealer tools) display this code with a failure-type suffix, such as U1838-00 or U1838:00; the base code U1838 is the same.

Manufacturer reference family

## GM: U1838

enLost Communication with Battery Charger Control Module on High Voltage Energy Management Communication Bus

Reference namespace: gm

Source revision: legacy-oem-dtc-r2-20260924

Reference family assigned by the production catalog. An entry in this family is not proof of a fault or ECU support on every listed vehicle.

## What should I check before using this definition?

Keep the full code, module, status and freeze-frame data. Confirm the vehicle’s make, model, year and current manufacturer service information before choosing a repair. This entry does not identify a failed part by itself.

[Organize a scan report or recording](https://obdlens.com/analyze/)

Source and applicabilityOBD Lens production library legacy-owner-2026-11-02-v84-evidence. This is a scoped technical reference, not a scan of your car. A catalog relationship does not certify that every ECU, year or engine returns the same signal or code definition.

[Read the reference method](https://obdlens.com/about/)

## What does U1838 mean?

Lost Communication with Battery Charger Control Module on High Voltage Energy Management Communication Bus. 1 reference families define this identifier: GM.

## Is U1838 a generic or manufacturer-specific code?

Check the reference scope shown above for this identifier.

## Can U1838 tell me which part has failed?

This entry does not identify a failed part by itself. Confirm the vehicle’s make, model, year and current manufacturer service information before choosing a repair.

## Continue with your vehicle

Use a specific profile to explore its enhanced signals and assigned code-reference families.

[Find a vehicle profile](https://obdlens.com/vehicles/)

## Read data from your car

Basic diagnostics and supported enhanced PID access remain free.

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OBD Lens reference library · catalog legacy-owner-2026-11-02-v84-evidence. [Sources and scope](https://obdlens.com/about/)

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Reference-family membership is not proof that a code applies to every listed ECU or vehicle. Runtime-ready definitions are not physical-vehicle validation. Unavailable readings must not be treated as zero. App and hardware sale availability must be checked separately.