Action before changing electronic control module
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Action before changing electronic control module
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When all checks have been completed according to the diagnostic procedure described for each diagnostic trouble code and no malfunction has been found, it is natural to assume that the control module/instrument is defective.
Considering 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.
Therefore, work through the following points very carefully before definitely pointing to the control module/instrument as the cause of the malfunction.
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1.
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Check once again that all points in the schedule for checking the operation of components, or all points in the diagnostic procedure for each diagnostic trouble code, have been completed.
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2.
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Study the wiring diagram of the circuit in question and make sure you understand how it works. Relevant parts of the technical description and the descriptions of operation explaining how components function electrically in Service Manual 3:2 "Wiring diagrams" may be helpful during this work.
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3.
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Check all grounding points. If you have already done so, do it once again.
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4.
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Check the power supply and the fuses for the electronic control module.
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5.
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Work through the points in "Keep in mind when fault tracing" on
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6.
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If the original malfunction still persists in spite of this, a new control module will have to be fitted.
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