A couple Questions on a 2001 gmc sonoma 2 wd

big al

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#1
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.
 
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#2
PCM commands AIR at engine start , energizes AIR pump relay and commands vacuum control solenoid valve ON which applies vacuum to the AIR shut-off valve, pump air is sent to check valves and flows into exhaust system... Pre cat o2 sensors se the lean out condition and confirm AIR flow... all this BS just at start up..

The ABS - I do NOT see a relay in the system (I will check time prrmitting) trouble finding info....
I am thinking the EBCM is not getting 12v or its intermittent- the valves are also not seeing 12v and coding same lack of voltage...
 

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big al

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#4
I didnt make it lol. Ill see this thing again tuesday. Im starting to feel like i should be looking at the grounds. I want to start there. It seems like its getting power (just did a quick check with test light but should put a meter on it to see volts) then start checking everything else. Got a late start on it so wanted to just make a few quick checks and the info rattle around the brain for a bit. I think as far as the AIR system goes, itll need the vacuum switch and pump.