CHECK ENGINE request
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).
Fault 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).
Condition
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 lamp can be activated from the transmission control module by means of the diagnostics instrument. Select "AUT TRANSMISSION". Select "ACTIVATE". Select "CHECK ENGINE".
Diagnostic procedure
1 Check the transmission control module output
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Plug a BOB into the engine control module's 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 switch to ON. The test lamp should now come on for about 1 second and then go out. If there is one.
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Does the lamp work OK?
Continue fault diagnosis as described in Service Manual 2:7 "Engine management system". Then proceed to point 3.
Continue with point 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 point 3.
Rectify the fault and continue with point 3.
3 Final check
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Connect the Scan tool diagnostics instrument.
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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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