Engine rpm dips, DRIVE
Fault symptom
Drop in engine idling speed when the selector lever is moved from P or N.
Condition
Shorting to ground or open circuit.
Diagnostic procedure
1 Check the transmission control module's output signal
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Connect the Scan tool diagnostics instrument.
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Turn the ignition switch to the ON position.
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Select "DRIVE". The diagnostics instrument should show OFF when the selector lever is in position P or N and ON when it is in position R, D, 3, 2 or 1.
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Is the reading correct?
Proceed to point 4.
Continue with point 2.
2 Check the engine management system's input signal
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Unplug the connector from the engine management system's control module.
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Turn the ignition switch to the ON position.
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Connect a test lamp to the connector as follows:
M4.1
to pins 86 and 58
M5.2:
to pins 69 and 54
Saab Trionic:
to pins 14 and 60. The test lamp should light up when the selector lever is in the P and N positions and remain off in the other positions.
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Is the signal OK?
Continue fault diagnosis as described in Service Manual 2:7 "Engine management system". Then proceed to point 4.
Continue with point 3.
3 Check the wiring
Check the continuity of the wiring between pin 11 of the transmission control module and pin 86 (M4.1), pin 69 (M5.2) or pin 14 (Saab Trionic) of the engine management system control module.
Is the wiring OK?
Continue with point 4.
Rectify the fault and continue with point 4.
4 Final check
Start the engine, move the selector lever to position D and check whether the fault symptom persists.
Does the fault symptom persist?
Continue with
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The remedial action taken was correct or the fault is of an intermittent nature.
