Powertrain, generic · Computer and auxiliary outputs

P0600 Serial Communication Link

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

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.

Likely causes

Internal module fault in the processor-to-processor link
Faulty module software (update available)
Open or short in a dedicated serial line between engine and transmission module (e.g. Subaru)
Low voltage, voltage dips or a poor ground or supply at the module
Fault in the transmission module at the other end of the line

Symptoms

  • 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

Repair estimate

DifficultyHardWorkshop job
Parts and labour€100–1,500
Time1–4 h

Typical range across vehicles; the real cost depends on what the testing finds.

What to check first

  1. Check battery voltage
  2. Check network wiring
  3. Scan all modules

Parts involved

engine control moduletransmission control moduleserial data line

Related codes

P0606P060AP0607P060CU0100U0101

References: law.cornell.edu, fordservicecontent.com, newtonnet.co.uk, fordservicecontent.com.