Lost Communication With Differential Control ModuleRear
Your vehicle's main computer has lost the ability to communicate with the rear differential control module, like a walkie-talkie losing signal. This prevents proper control of traction and all-wheel drive functions.
The ECM expects periodic communication messages from the rear differential control module over the CAN bus network. If no valid messages are received within a timeout threshold, the ECM sets this code and disables rear differential features.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| CAN Bus Message Timeout | Message received every 10-100 ms | No valid message received for 500-2000 ms |
| Message Checksum Validation | Checksum matches expected value | Checksum fails or message corrupted |
Code U0136 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, U0136 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.