P0600Serial Communication Link
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- P0600 means a serial data link that the module relies on has failed. At Ford it is the internal link between the main processor and the monitoring processor ('quizzer') of the electronic throttle safety concept: if data cannot be exchanged or check bytes are invalid, the code sets within about a second (diesel: 5 s), usually with the check engine and wrench lamps and a throttle failure mode such as an RPM limit. Subaru (also sold as Saab 9-2X) uses it for the dedicated serial line between engine and transmission module. GM does not use P0600. Lost CAN messages from a named module are reported separately as U0100 and following. Before replacing anything: check battery, grounds and supply, look for a software bulletin, reprogram with a stable power supply, and replace the module only if the code returns.
- What you may notice
- Check engine light, at Ford also the wrench lamp
- Reduced power or RPM limit (throttle failure mode)
- Harsh shifts or transmission limp mode where the line links engine and gearbox
- Other monitors such as the catalyst monitor do not run
- Likely causes
- LikelyInternal module fault in the processor-to-processor link
- PossibleFaulty module software (update available)
- PossibleOpen or short in a dedicated serial line between engine and transmission module (e.g. Subaru)
- PossibleLow voltage, voltage dips or a poor ground or supply at the module
- RareFault in the transmission module at the other end of the line
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Hard · Usually a job for a workshop.Typical cost: €100 – €1,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.