Engine speed dipping, DRIVE
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Engine speed dipping, DRIVE
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Fault symptoms
Engine idling speed drops when the selector lever is moved from P or N.
Conditions
Short circuit to ground or open circuit.
Diagnostic procedure
1 Check the output signal from the control module
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Connect the diagnostic tool.
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Turn the ignition to the ON position.
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Select "DRIVE". The diagnostic tool should display OFF with the gear lever in positions P and N, and ON with the gear lever in positions R, D, 3, 2, 1.
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Are the readings correct?
Proceed to point 4.
Continue with step 2.
2. Check the input signal to the engine management system
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Unplug the connector from the engine control module.
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Turn the ignition 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 correct?
Continue fault diagnosis in Service Manual 2:7 "Engine management system". Then continue with step 4.
Continue with step 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.
