# Electronic Brake Control Module Lost Communication with Engine or Transmission Control Module

Source: https://obdlens.com/codes/u186a/
Last built: 7508d481ba6c398f25ed

[Diagnostic knowledge](https://obdlens.com/knowledge/) / U186A — Electronic Brake Control Module Lost Communication with Engine or Transmission Control Module

U186A

U186A is described as “Electronic Brake Control Module Lost Communication with Engine or Transmission Control Module” in the GM reference. 

Some scan tools (for example GM and Ford dealer tools) display this code with a failure-type suffix, such as U186A-00 or U186A:00; the base code U186A is the same.

Manufacturer reference family

## GM: U186A

enElectronic Brake Control Module Lost Communication with Engine or Transmission Control Module

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 U186A mean?

Electronic Brake Control Module Lost Communication with Engine or Transmission Control Module. 1 reference families define this identifier: GM.

## Is U186A a generic or manufacturer-specific code?

Check the reference scope shown above for this identifier.

## Can U186A 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.

[Explore OBD Lens App](https://obdlens.com/app/)

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

---

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.