Fault Conditions

P1253

Throttle Motor. Full PWM in Open Direction During Cranking.










Fault symptoms
- CHECK ENGINE.
- Idling speed incorrect.
- Cruise control not working.
- The engine does not start when the DTC appears. The throttle does not open during the start attempt.
- Starting difficulties, especially when the 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
- Crankshaft rotating but engine not yet started. Main relay voltage exceeding 5 V.

Fault criteria
- Throttle motor receiving 100% PWM in opening direction.

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 refer to "Fault diagnosis, general". Description of On-Board Diagnostics)

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

Diagnostic help
A mechanical or electrical fault is preventing the throttle from opening during start. Main relay voltage supplying the control module is OK.

Functions in the diagnostic tool related to the fault:
- Activate output for throttle motor.

For more information, refer to scan tool testing. Menu Read Values

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.

Proceed to Diagnostic Procedures Diagnostic Procedure