The AD 400 Tech 2 scan tool

The 'Daddy' of all special SAAB tools, however, is the AD 400 Tech 2 Scan tool. In effect, this is a hand held computer which uses PCMCIA cards onto which software is loaded for the appropriate GM family model (SAAB, Vauxhall, Suzuki etc). The scan tool is connected to the vehicle via the On Board Diagnostic (OBD) or CANBUS (controller area network bus) socket and draws power from the car.

It is hard to work on SAAB cars regularly without access to a Tech 2 scan tool because the engine management systems have evolved since the days of the early 9000. Then, turning on the ignition and waiting for the management light to flash a certain number of times gave technicians a good idea what was wrong.

Now, cars like the 9-5 have two interconnected bus systems: iBus and pBus. The iBus is basically concerned with instrumentation while the pBus related to the power unit, monitoring the engine and transmission. Sensors on the pBus are interrogated all the time by the Trionic management system and if an unexpected value is returned or no signal is received, a diagnostic trouble code (DTC) is triggered.

The Tech 2 can retrieve DTCs: example P1805 and they can be looked up with the Workshop Information System (WIS) in the case of 9-5s or with later 9-3s, it pays to have the Tech2 connected directly to a laptop, so the fault can be read directly by WIS.

In addition to being able to retrieve and clear DTCs, a Tech 2 can also be used to reset service messages, alter locking logic, recalibrate the speedometer (when 16“ wheels are changed to 17” or vice versa), clone security chips for keys or update engine management software. A common need for a Tech 2 arises when a SAAB is being dismantled - it is pointless recovering the radio/cd/cassette head unit unless it has been divorced from the car it was originally fitted to. Head units are married to individual cars and cannot be unlocked or decoded after they have been removed. A Tech 2 is required, of course, to marry a unit that has been divorced from another car to a different vehicle. Be advised that a Tech 2 kit with extras and software will cost around £3000 - for this reason, dealers will habitually charge owners for reading or clearing fault codes.

If you decide you cannot undertake a specific job on your SAAB without using special tools, you need to consider whether it isn't more prudent to engage a SAAB specialist to carry out the job for you. This is because the tools are fairly pricey and are unlikely to be held in the UK (special order). Suppliers advise us that there is likely to be a long lead time for tools because there is no way to escape expensive carriage costs and the only sensible way to go is to place a consolidated order for a number of tools.

Source: SeriousSAAB