P1605

Read the instructions below then start the fault diagnostic procedure.

Symptom: CHECK ENGINE. Idling speed incorrect. Cruise control not working.

P1605

Fault symptoms

•	CHECK ENGINE.

•	Idling speed incorrect.

•	Cruise control not working.

On-Board Diagnostics

Type of diagnosis:

-	Continuous. But interrupted when fault criteria fulfilled and will not restart until next driving cycle.

Enable criteria:

-	Ignition in ON position.

Fault criteria:

-	Serial communication error between processors 339 and 592.

Dependents:

-

None.

System reaction to a fault:

-	Throttle control goes into limp-home mode. The limp-home solenoid will be activated 5 times in succession each time the ignition is turned on until the fault has been rectified and the trouble codes cleared.

OK report:

-	Accelerator pedal has been depressed at some time and then fully released. 120 s has expired since then without fault criteria being fulfilled.

Fault handling: (For more information, see .)

-	CHECK ENGINE goes on immediately and can be turned off only by clearing the trouble codes.

Diagnostic help

Fault diagnosis concerns internal control module fault.