Hi All, and thanks for the replies.
Sorry about the delay but wanted to be sure it was a reliable fix.
Dave, you are right about the ECU testing but my friend who sent the unit off wanted to do something, so that is what he did. Like I said I have not had to go this far into this system before, I will not get caught again (hopefully).
I did spend a lot of time searching the archives and Pico's website with no luck for some reason.
Anyway, made basic resistance tests of old cam sensor to find coil between 2&3 open circuit, so at least I new that one was faulty. Made resistance and inductance tests of new one. Between pins 1&2- 12.7 Ohms/ 1.15 mH, 2&3- 0.7 Ohms/ less than 0.03mH. On the basis of the resistance between 2&3 I recommended a new sensor. Before fitting it I measured again, the latest one was very close to the previous new one! It was fitted anyway and guess what, out went the light and the code could be cleared.
Intending to scope the first replacement sensor I got the scope out to warm it up and after a couple of minutes the display went blank, I did not manage to repair it until after the second replacement sensor was fitted, which did give results as per the samples Dave supplied. Due to time issues it was not possible to refit the first replacement and see what was wrong with it unfortunately.
I always preach to others "just because it's new does not mean it's a good one" and fell in the trap myself. Both sensors genuine GM by the way.
Yes, I would love to have a Picoscope but unfortunately financial constraints mean no chance at the moment. The scope I use is quite old, it's an HP 400Msample/Sec DSO, but I do have 3 of them, one to use and 2 for spares!
Thanks again for advice and info, Shaun.