P1253
Read the instructions below then
start the fault diagnostic procedure.
Symptom: CHECK ENGINE.
Idling speed incorrect.
Cruise control not working.
Engine does not start when DTC generated. Throttle does not open for starting.
Starting problems, especially when engine is cold.
Throttle Motor. Full PWM in Open Direction During Cranking.
Fault symptom
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Idling speed incorrect.
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Cruise control not working.
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Engine does not start when DTC generated. Throttle does not open for starting.
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Starting problems, especially when engine is cold.
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On-Board Diagnostics
Type of diagnosis:
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Continuous. But interrupted when fault criteria fulfilled and will not restart until next driving cycle.
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Enable criteria:
(Conditions that must be fulfilled before the diagnosis can be performed.)
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Crankshaft rotating but engine not yet started. Main relay voltage exceeding 5V.
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Fault criteria:
(After enable criteria have been fulfilled, the diagnosis checks whether fault criteria are fulfilled.)
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Throttle motor is receiving 100 % PWM in opening direction.
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Dependents:
(Occasionally after fault criteria have been fulfilled, a number of other diagnostics must report OK before the trouble code can finally be generated.)
System reaction to a fault:
(After fault criteria have been fulfilled, certain measures will occasionally be taken.)
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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.
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OK report:
(The diagnosis can be included as a dependent for another diagnosis and must therefore report OK even if it is continuous. The OK report is also used in fault handling to decrement the fault counter.)
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Accelerator pedal has been depressed at some time and then fully released. 120 s has expired since then without fault criteria being fulfilled.
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Fault handling:
(See “Fault diagnosis, general” for more information.)
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CHECK ENGINE goes on immediately and can be turned off only by clearing the trouble codes.
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Diagnostic help
A mechanical or electrical fault is preventing the throttle from opening during starter motor cranking. The main relay voltage supplied to the control module is OK.
Functions in the diagnostic tool related to the fault:
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Activation of output for throttle motor.
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See also the description of activating functions under ”Fault diagnosis, general” for more information.
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.
