9-3 Coupe (9400) L4-2.0L Turbo (B204) (1999)
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EDC 15 And DAH
EDC 15 and DAH are each connected to the data link connector pin 7 through a communications lead. The diagnostic tool communicates digitally and
serially with the selected system. Digitally means that the voltage difference between the lead and ground has only two values, in this case about 0 V and
B+. The information is coded so that different combinations of 0 V and B+ pulses have different meanings, like which system is to be called.
Serial means that the information is sent in packets" which are transmitted one after the other in rapid succession.
Diagnostics
If none of the systems can be contacted, the fault may be either in the car or the diagnostic tool. If the diagnostic tool can contact one of the systems
concerned in another car, then the fault is in the car.
In this case, first make sure that the control module is awake (as described in the technical data). If it is awake then the fault is probably in the lead
between the data link connector and the control module.