Before control module replacement
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Before control module replacement
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When all checks have been carried out in accordance with the diagnostic
procedure and no fault has been detected, it is natural to assume that the control module is
defective.
In view of the fact that the control module is a high-quality component and also a costly
one, it is important to make as accurate a diagnosis as possible.
Check through the following points extremely carefully before you definitely pinpoint the
control module as the cause of the fault.
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1.
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Go over all the points once
again, checking the operation of systems and components, and also check that all points in
the relevant code's fault diagnosis schedule have been covered.
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2.
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Study the wiring diagram of the appropriate circuit and learn how it works. If
necessary, consult relevant parts of the technical description and the description of electrical
circuits and their operation in Service Manual 3:2 "Wiring diagrams".
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3.
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Check all grounding points. If you have already done so, check them
once again.
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4.
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Check the power supply and the control module fuses.
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5.
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Experience gained from model year 1993 cars shows that the majority of all
control modules returned in connection with repairs carried out under warranty were in perfect
working order.
Be restrictive with the replacement of control modules.
Unnecessary replacement of control modules represents a major expense for Saab
Automobile and Saab dealers. Carefully consider all possible causes of the fault before
changing the control module.
After fitting a substitute control module for testing purposes, always refit the original
control module.
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6.
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If the original fault still persists in spite of all this, the control module will have to
be changed.
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