CHECK ENGINE - requirements
Symptom: The CHECK ENGINE lamp (MIL) does not light up in spite of a transmission fault that activates the limp-home mode (emergency operation program).
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CHECK ENGINE - requirements
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Fault symptoms
The CHECK ENGINE lamp (MIL) does not light up in spite of a transmission fault that activates the limp-home mode (emergency operation program).
Conditions
A fault in the ongoing drive cycle generates a diagnostic trouble code and causes the CHECK ENGINE lamp (MIL) to light up.
Diagnostic help
The CHECK ENGINE indicator lamp can be activated from the transmission control module with the diagnostic tool. Select "AUT TRANSMISSION". Select "ACTIVATE". Select "CHECK ENGINE".
Diagnostic procedure
1 Check the transmission control module output
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Connect BOB to the engine management system connector but do not connect the control module.
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Connect a test lamp to pins 61 and 60 (Saab Trionic), pins 65 and 58 (M4.1) or pins 39 and 54 (M5.2).
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Turn the ignition key to the ON position. The test lamp should go on for about 1 second and then go out. If there is an OBD II trouble code stored, the test lamp will flash. Otherwise, the lamp will remain off.
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Is the lamp functioning correctly?
Continue fault diagnosis in Service Manual 2:7 "Engine management system". Then continue with step 3.
Continue with step 2.
2 Check the wiring between the transmission control module and the engine control module
Check the continuity of the wiring between pin 5 of the transmission control module and pin 61 (Saab Trionic), pin 65 (M4.1) or pin 39 (M5.2) of the engine control module.
Is the wiring OK?
Continue with step 3.
Rectify the fault and continue with point 3.
3 Final check
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Connect the diagnostic tool.
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Select "CHECK ENGINE". The lamp should start flashing.
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Lamp flashing?
The remedial action taken was correct.
Continue with
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