What P0600 means
Serial Communication Link Malfunction
How to diagnose
- Read freeze frame data. When P0600 set, your ECU snapshotted every sensor at that moment. This tells you what the car was doing when the fault triggered — RPM, load, coolant temp, throttle position, fuel trims. Almost always enough info to figure out the cause without further testing.
- Check for related codes. If you have P0600 plus other codes, fix the earliest one in the chain first — a single root cause often triggers multiple codes.
- Cheap fixes first. For most codes, the order is: inspect connectors + wiring (free), check for vacuum leaks (cheap), replace sensor (moderate), replace mechanical part (expensive). Follow that ladder before dropping money on parts.
Manufacturer-specific descriptions
Different manufacturers use P0600 for slightly different failure modes:
| AUDI | Defective PCM (Power Train Control Module), Defective PCM data bus wiring/connections, Defective PCM data bus ground circuit(s), Defective PCM or other control module controlled output devices, Defective CAN bus communication |
| BMW | Serial Communication Link |
| FORD | Serial Communications Link Malfunction |
| HONDA | Multiplex Control System Troubleshooting |
| MITSUBISHI | Serial Communication Link Malfunction; Serial communication link |
| NISSAN | Serial Communication Link Malfunction |
| VOLKSWAGEN | Serial Communication Link Malfunction |
Read P0600 on your own car
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