Lost Communication With Battery Energy Control Module B
Your car's main computer lost contact with the battery management module, like a walkie-talkie losing signal. This prevents proper power distribution and energy management in the vehicle.
The ECM monitors CAN bus communication signals from the Battery Energy Control Module B at regular intervals. It expects valid data packets within specific timeframes; failure to receive these signals triggers a timeout fault. The module controls auxiliary battery charging, power distribution, and energy management functions.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| CAN Bus Message Timeout | Valid message received every 10-100ms | No valid message received for >500ms |
| Module Response Status | Module responsive with valid checksums | No response or corrupted data packets |
Code U0112 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, U0112 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.