I though I'de share this piece of knowledge with eveybody

After driving for about a mile the yellow car/spanner indicator light came on but the vehicle ran OK with no apparent problem. This went on for about a month, start the car OK, after a mile the light would come on again. Took it to my local non-Vauxhall garage to see if the could read the ECU error codes and point me in the right direction to where the fault might lie but they could only read the general codes.

I checked the usual suspects listed in the Haynes manual and found nothing so I gave up.

One thing I did notice was that when I started there was a puff of black smoke, normal running there was no smoke, so decided to check the glow plugs. Checking the plugs with a multimeter I found one of them had gone open circuit, so I fitted a new one.

This action stopped the puff of black smoke when the engine was started and it also cured the yellow car/spanner indicator light coming on.