With an ISAT Scan Tool

Fault diagnosis with an ISAT, LH 2.4 (M1990-)

Model year 1990 and later cars with a B202 engine and the LH 2.4 fuel injection system have additional diagnostic facilities and are consequently equipped with new control modules. A number of new fault codes have been added to the self-diagnosis function using ENGINE CHECK lamp flashes, and it will also be possible to carry out fault diagnosis by means of an ISAT.

However, use of the ISAT involves the addition of a number of control command codes by means of which the operation and current status of components can be checked.

As before, fault diagnosis can also be carried out by means of an LH system tester.

The fault diagnosis schedule with an ISAT does not include more fault codes than are incorporated in the self-diagnosis function, but will be fully developed for model year 1991 cars.






Before starting fault diagnosis

Note: Never unplug the connector from the control module or disconnect any of the battery cables before the contents of the control module memory have been transferred to the ISAT.

Apart from a thorough knowledge of the system, successful fault diagnosis on the LH system also requires the use of Saab's LH system tester or an ISAT diagnostics instrument.

Since the LH system's integrated self-diagnosis function continuously monitors and records the majority of possible faults, both permanent and intermittent, it is extremely easy to use an ISAT to identify the fault, rectify it and afterwards check that the system is in perfect working order.




The system's integrated self-diagnosis functions, combined with the facilities provided by an ISAT, make for faster and above all more accurate fault diagnosis. The risk of replacing good components is reduced while service and repair costs can be kept down.


Is the fault in the LH system?

Sometimes the LH system is suspected of being faulty when the fault really lies in the engine or some other auxiliary system. For this reason, remember to check the following points before starting fault diagnosis on the system.

- Battery condition
- Engine condition
- Charging system
- Other auxiliary systems
- Cable connections
- Grounding points