Fault diagnosis strategy for electronic systems
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Fault diagnosis strategy for electronic systems
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1.
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The customer's description of the problem constitutes the basis for the fault diagnosis strategy.
If necessary, the customer must demonstrate the trouble on the car to avoid misunderstandings.
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2.
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In certain cases, the function may be correct.
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2.a.
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Good product knowledge is required to decide this.
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2.b.
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If the function is correct, this must be explained to the customer.
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3.
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If the function is considered faulty, the car should be repaired.
Saab's fault diagnosis strategy assumes that the technician is familiar with the customer's description of the problem. So note the customer's complaint and any other observations on the work order.
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4.
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The technician obtains a readout of the diagnostic trouble codes from
all
systems.
A malfunction in one system can often be caused by a fault in another system.
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5.
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The car may contain diagnostic trouble codes which are secondary faults or which have been incorrectly generated.
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5.a.
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Compare the customer's complaint with the symptom descriptions for the various diagnostic trouble codes. EPSI has a fast search path for this.
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5.b.
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If the symptom description for a diagnostic trouble code matches the customer's complaint, this code is probably caused by the primary fault.
Repair in accordance with the instructions.
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6.
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If there is no match with the diagnostic trouble codes, fault diagnosis on the basis of symptoms can be carried out.
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6.a.
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In EPSI, search under fault diagnosis on the basis of symptoms in the system where the fault has occurred.
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6.b.
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If the symptom description in the current system matches the complaint, the right fault diagnosis description has probably been found.
Repair in accordance with the instructions.
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7.
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If there is no match with diagnostic trouble codes or symptoms, the technician must diagnose the fault himself.
A final check must be carried out after the repair.
Good technical product knowledge is required to solve this type of problem.
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