Lost Communication With Navigation Control Module
Your car's main computer has lost connection with the navigation/infotainment module, like a phone losing WiFi to your home router. The systems can't talk to each other over the internal network.
The main ECU continuously monitors CAN bus communication signals from the navigation control module at regular intervals. It expects to receive valid data packets within specific timeouts; if messages stop arriving or are corrupted, a communication timeout fault is triggered.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| CAN Bus Message Timeout | Navigation module responds within 100-500 ms | No response for >3 consecutive communication cycles |
| Signal Integrity | Valid CAN checksum and data format | Corrupted or missing data packets detected |
Code U0163 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, U0163 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.