Lost Communication With Restraints Occupant Sensing Control Module
Your car's main computer has lost the ability to talk to the airbag and seatbelt sensor module, similar to a walkie-talkie losing its signal. This communication failure prevents the system from knowing if passengers are present or positioned safely.
The main ECU continuously sends CAN bus messages to the occupant sensing control module to verify connection status and receive passenger detection data. It monitors for valid acknowledgment responses within specific timeout windows. Loss of communication occurs when no valid messages are received for a defined period, typically 100-500 milliseconds.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| CAN Bus Message Response Time | 50-100 milliseconds | No response for >500 milliseconds |
| Occupant Sensor Signal Validity | Valid periodic updates received | No valid data frames detected |
Code U0154 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, U0154 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.