Lost Communication With Body Control Module A
Your engine computer lost its connection to the body control module, like two walkie-talkies that can't hear each other anymore. This prevents the engine from communicating with systems that control lights, windows, and other electrical functions.
The ECM monitors CAN bus communication signals to the body control module (BCM) at regular intervals. If the ECM fails to receive expected handshake messages or data frames within a timeout period, it logs this fault code. Communication loss typically occurs when bus voltage drops below threshold or signal integrity degrades.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| CAN Bus Voltage | 11.5-12.5V (12V systems) | Below 9V or above 16V |
| BCM Message Reception Timeout | Message received every 10-100ms | No message received for >500ms |
Code U0141 is a moderate fault. You can generally drive to a workshop, but avoid long trips or high-load driving (motorway, uphill towing) until it is diagnosed. If the code keeps returning after clearing, or if you notice the symptoms listed above worsening, do not delay professional diagnosis. Many moderate codes have multiple possible root causes — a mechanic with live OBD data can identify the exact fault more efficiently than part-by-part trial and error.
Once the fault is repaired, U0141 can be cleared using any OBD-II scanner. Connect the scanner, navigate to "Clear Codes" or "Erase DTCs," and confirm. The check engine light turns off immediately.
The code will return if the root cause was not actually fixed. The ECM re-detects the fault within 1–3 drive cycles and sets the code again.