The engine management system has a built in diagnostics plug (Assembly Line Diagnostic Link – ALDL) which is mounted in the passenger footwell on both LHD and RHD cars.
Stored fault codes can be read by Bridging terminal A (Black wire) & terminal B (white wire) with the ignition off
The simplest way to do this is by using a short piece of wire or paper clip. Lotus also supply a bridging plug p/n T000T0909. Turn the ignition on and monitor the amber Check Engine Light on the instrument cluster. It should emit a series of flashes with a short pause between them.
1 flash followed by 2 flashes indicates code 12. (no faults found). This will be repeated 3 times and then any stored fault codes will follow. Each will be repeated 3 times. After the last code is displayed code 12 will be displayed. Check any displayed codes against the list.
By using ElanScan. It is possible to see real time readings for the sensors using a laptop (running windows 95 or higher operating system). and either purchasing or making your own ALDL interface cable
Once you have installed the software and connected the cable to the ALDL plug you can start logging and saving the information into a file. To see the kind of data available.You can download a typical log file taken from my car earlier this year.