Lost Communication With Vehicle Immobilizer Control Module
Your car's main computer has lost its conversation with the immobilizer security module, like a radio losing its signal. Without this communication, the immobilizer can't verify your key is authentic, preventing the engine from starting.
The ECM expects periodic CAN bus messages from the immobilizer module confirming key authorization status within a set timeout window. When no valid signal arrives after multiple polling attempts, the ECM sets a communication fault and blocks fuel injection and ignition.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Immobilizer CAN Message Timeout | Message received every 100-500 ms | No valid message for >1 second |
| Immobilizer Authorization Signal | Valid key recognized, signal active | No signal or invalid/expired authorization code |
Code U0167 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, U0167 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.