Fault diagnosis strategy for electronic systems: Notes
- The customer's description of the problem constitutes a basis for the fault diagnosis strategy.
If necessary, the customer must demonstrate the trouble on the car to avoid misunderstandings.
- In certain cases, the function may be correct.
- 2.a. Good product knowledge is required to decide this.
- 2.b. If the function is correct, this must be explained to the customer.
- If the function is judged to be faulty, the car should be repaired.
- 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.
- The car may contain diagnostic trouble codes which are secondary faults or which have been incorrectly generated.
- 5.a. Compare the customer's complaint with the symptom descriptions for the various diagnostic trouble codes. EPSI has a fast search path for this.
- 5.b. If the symptom description for a diagnostic trouble code matches the customer's complaint, this diagnostic trouble code is probably caused by the primary fault.
Repair as per instructions.
- If there is no match with diagnostic trouble codes or symptoms, the technician must diagnose the fault himself.
- 6.a. In EPSI, search under fault diagnosis on the basis of symptoms in the system where the fault has occurred.
- 6.b. If the symptom description in the current system matches the complaint, the right fault diagnosis description has probably been found.
Repair as per instructions.
- Certain fault symptoms can be remedied by reprogramming the control module.
- 7.a. Does the customer complaint stem from a known software problem in a programmable control module?
- 7.b. Reprogram the control module following the instructions in SPS.
- 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.
- The car is ready.