some years ago had to replace the srs ecu on my ZS. Pscan would not connect to it... and I also noticed that when turning the ignition on, the SRS did not flash off and then back on to indicate that it had detected a fault. bought a new ecu arrived next day, problem solved.
an iffy wire going to the solenoid can be fine for months, then every now and again, I have no click on the starter when turning key and have to open boot to wiggle cable on solenoid. Usually this works but sometimes no amount of wiggling will get it to work when on my own.
i had this for years on my v6 mg zs, eventually a change of starter and now fine.
hi, does not sound quite the same as what i had a few years ago. to fix it all i did was identify the srs ecu part number - having removed the parts needed to access it, then i bought a matching part number off ebay. changed it over, and it worked straight away and has been ok since. There are different part numbers for those cars with pass and driver airbags or just a drivers one.
i think you will also have to see what philip says about what pscan is doing..
I had a similar problem some years ago. the pscan had been connecting ok to my 03 mg zs v6, but one day the srs light came on, and when i connected the pscan it would not connect anymore. it turned out that the srs ecu had failed and once i replaced it ,it was fine again.
the pscan unit does more than just list a code, it comes up with some text that helps as well.
i had noticed when i had the problem - that when i turned the ignition on the srs did not flicker off then on again as it had done previously - which helped me to think it was trhe srs ecu that had failed.
i have used my pscan mainly for srs problems and it has been very useful.
tried this today on one of my 54 plate zr's - a 1.8 120hp. connected easily in iso and then tried bmw - also worked (had to turn ign off and on again as expected) results were the same... changing back from bmw to iso did not need to turn ign off and on again as i had expected to do.
my impression was that it connected slightly faster in iso mode, but not much in it.
i have 2 other zr's so could try it on those if you want, one is 54 plate 1.4 the other is a 02 1.8 120hp.
keith