Lost Communication With Restraints System Sensor E
Your vehicle's computer has lost contact with a sensor in the airbag/seatbelt system, like a phone losing signal from a tower. The safety system can't communicate properly and may disable airbags or warning features.
The ECU monitors CAN bus communication signals from restraint system sensors (seatbelt switches, occupancy sensors, impact detectors). It expects periodic heartbeat signals within defined time windows. If signals drop below threshold or timeout occurs, a communication fault is triggered.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| CAN Bus Signal Timeout | Signal received every 10-100ms | No signal for >200ms or bus error detected |
| Message Validation | Valid checksums and data integrity | Corrupted or missing message data |
Code U0174 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, U0174 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.