Before getting out the Tech 1 you should perform a through visual inspection of the system. You may get lucky and find the problem. I do not know of any other way to get the error codes out except with a Tech 1, the right cable, and the specific cartridge. Guessing what is causing the light to go on can become expensive. Make sure all of the plugs are fully seated and both fuses are in. There is also a supplement to the manual you will need for the SIR system.I have to diagnose an airbag light on a V8 Esprit. I have a Tech 1, but not the Lotus cartridge. Is there PC software available, or some other way to read the codes for diagnosis?