Fault Conditions

P1670

Limp-home Relay, Open Circuit Or Short To Ground







NOTE: The relay/electrical circuit that activates the throttle's limp-home function is faulty.

Fault symptoms
^ CHECK ENGINE.
^ Cruise control not working.
^ Throttle control may go into mechanical limp-home mode. P1251, P1260 or P1263 could be generated as a secondary fault.
^ Starting problems, especially when engine is cold

On-Board Diagnostics

Type of diagnosis:
^ Continuous. But interrupted when fault criteria fulfilled and will not restart until next driving cycle.

Enable criteria:
^ Engine running. Main relay voltage exceeding 10V. Output not active.

Fault criteria:
^ Output voltage below 2V for more than 1 s.

Dependents:
^ None.

System reaction to a fault:
^ Cruise control blocked.

OK report:
^ Enable criteria fulfilled and fault criteria not fulfilled within 60 s.

Fault handling: (For more information, Fault Handling III, Other Emission-Related Components and Function)

^ Type III.

Diagnostic help
Fault diagnosis concerns electrical fault in connecting leads or in the relay.

Checking the wiring
Jiggle the wiring harness at several points and in different directions to detect intermittent breaks and short circuits. Observe the multimeter, diagnostic tool or test lamp during the check.