Wow Eric, recently I’ve discovered that this very same method is actually used in my 1995 Citroen AX to read the codes from the ECU.
In my case the codes can be read by grounding one of the two pins (the one on the left, holding the connector’s spring downward) of the ECU diagnostic port for about 5 seconds; then the check engine light turns off, then blinks on once, then a pause, then twice (code 1-2 = start of diagnosis).
Then you have to ground the pin again , and it will start with the error codes (if there is any).
In the end the code will be two slow blinks (code 1-1 = end of diagnosis)
To clear the codes is as easy as grounding the pin for about 10 seconds 🙂
Very interesting!
And by the way, my code was 2-2 (two fast blinks, a pause, two fast blink) which meant I had a faulty idle control valve/stepper motor; I kinda already knew it was faulty, but wanted to counter-check my own diagnosis with that of the ECU 😆 before replacing the part!
I’d really like to do a video to explain the process, but I have some big hurdles
– very small and dark garage
– no real videocamera, only a cellphone or a camera (the one for the still-pictures)
– not very good english pronounciation 😛
I could post some pictures however 😉
For the moment…
…Live long and prosper (and stay dirty!)
10nico