Dashboard Integrated Central Electronics (Dice)

Fault Diagnostics Strategy For the Electronic System

1 The customer's description of the problem is the basis for fault diagnosis strategy.
It is possible that the customer must demonstrate the problem on the car to avoid a misunderstanding.
2 In certain cases, the function may be operating correctly.
a A good product knowledge is required to be able to determine if this is the case.
b If the function is operating correctly, this must be explained for the customer.
3 If the function is judged to be faulty, it must be repaired.
Saabs fault diagnosis strategy is based on the technician's knowledge of the customer's description of the problem. Therefore, note the complaint and any additional information or the work order.
4 The technician reads out the diagnostic trouble codes from all systems.
A functional fault in one system may well be caused by a fault in another system.
5 There may be diagnostic trouble codes in the car that are secondary faults or that are incorrectly set.
a Compare the customer's complaint with the symptom descriptions of the different diagnostic trouble codes. EPSI has a quick search path for this.
b If the symptom description of a diagnostic trouble code corresponds with the customer's complaint, this diagnostic trouble code is probably caused by the primary fault.
Repair according to the instructions.
6 If there is no corresponding diagnostic trouble code, the fault can be diagnosed from the symptom.
a Search the EPSI under fault diagnosis of symptom in the system where the fault has occurred.
b If the symptom description in the system in question corresponds with the complaint, it is probably the correct fault diagnosis description.
Repair according to the instructions.
7 If there is no corresponding diagnostic trouble code or symptom, the technician must diagnose the fault himself.
A final check must be made after repairs.
A good technical product knowledge is required to solve this kind of problem.
8 The car is ready.

General fault diagnosis of electronic Systems

Control module
When the control module is supplied with current, the processor in the control module is activated. The processor then reads the instructions that are stored in the control module memory.
The control module is programmed to read the inputs and activate the outputs. If the control module is faulty, the diagnostic trouble code "Internal control module fault" is set.
In order for the system to function, the control module must be supplied with current. That the control module is supplied with current and that the processor is activated can be detected with the diagnostic tool as it can then make contact with the control module.

Outputs
The system controls a number of functions with the help of various actuator units, e.g. an injector or a bulb. If the system is to be able to carry out its functions, the actuator units must be activated. Therefore, they must be in contact with the control module and have the correct power supply or grounding.

Inputs
In order for the control module to be able to control the actuator units, the system sensors must supply the control module with the correct values.
The function of the sensors can be checked with the diagnostic tool.