Ill be working on this 2001 gmc sonoma, 4.3 litre, 2 wheel drive truck soon. 1st is the ABS system, getting a bunch of codes all at the same time, CO265 (ebcmm relay circuit )then all the rest follow it, CO245,CO251,CO246,CO242,CO252,CO241. Is it possible this relay works until warm then acts up? The Abs works for about a few blocks to a mile then all these codes come backat the same time. I guess its been intermittent with weather but now is always a problem. Could this relay be acting up? Also any ideas on the PO410 (air injection system ) not too familiar with this system , looks to be a few different solenoid valves in the lines and a pump. He states it has made noise before but was also intermittant. I hope to have this one done before the weekend.