Description of On-Board Diagnostics

SPECIAL TOOL
The Saab ISAT scanner, or an aftermarket equivalent, is needed to perform this procedure.

FAULT DIAGNOSIS WITH THE ISAT SCAN TOOL
The ISAT Scan Tool is primarily designed for diagnosing faults in electronic systems incorporating self-diagnostics circuitry. In systems of this kind, both permanent and intermittent faults are diagnosed and stored in the system's control modules by means of the ISAT Scan Tool, the stored information is copied and the fault presented in the form of a five-digit code on the ISAT Scan Tool display.

DATA LINK CONNECTORS AND SYSTEM NUMBERS
The ISAT Scan Tool should be plugged into the GREEN data link connector located under the right-hand front seat. System 7 is used for fault diagnosis on the airbag system.

ISAT Command Codes:

ISAT SCAN TOOL COMMAND CODES
When the ISAT Scan Tool is used for simulating signals or functions by sending command codes to the control module, the result is shown on the display in the form of an alphanumeric code (a combination of letters and numbers).

IMPORTANT:
^ Use the green data link connector located under the right-hand front seat.
^ System number 7 applies to the airbag system.
^ Obtain readouts and make a note of all the stored diagnostic trouble codes before disconnecting the battery or control module.
^ If communication cannot at first be established between the ISAT Scan Tool and the control module, make several fresh attempts (wait about 40 seconds with the ignition switched OFF - then try again). If communication still cannot be established, check the wiring between the control module and the data link connector.
^ When the contents of the system's fault memory have been transferred and stored in the ISAT Scan Tool, the diagnosis itself has been completed. The faults are then available in the form of 5-digit trouble codes. Fault diagnosis can now be continued in accordance with the recommended diagnostic procedure for the system in question.
^ To avoid damaging the control module, always check that the ignition is switched OFF before unplugging the connector.
^ When diagnosing faults, it is recommended that you first check that the control module is properly grounded and that all supply voltages are correct.
^ Unplug connectors and check that the connections and pins are undamaged.
^ When first detected, each fault is assigned a trouble code signifying a permanent fault. If the fault disappears, the fault is instead assigned a trouble code signifying an intermittent fault.
^ Since all signal levels around 12 V are proportional to battery voltage, they should be used as guidance only.