Lost Communication With Radio
Your vehicle's main computer has lost the ability to talk to the radio module, like a phone losing connection to a Bluetooth speaker. The radio may not function properly, and other infotainment features could be affected.
The main ECU monitors CAN bus communication signals to the radio module at regular intervals. If the ECU fails to receive expected handshake messages or acknowledgment frames from the radio within a timeout window, it registers a lost communication fault.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| CAN Message Response Time | < 100 ms round-trip | > 500 ms or no response |
| Bus Signal Voltage | Dominant: 0-1V, Recessive: 3.5-5V | Stuck low or irregular transitions |
Code U0184 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, U0184 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.