no change with the o2’s disconnected

 

now I was popping codes for both o2’s and getting this on the reader when check engine came on

 

Not just disconnected. Physically removed from the exhaust system. Only concerned about the pre-cat sensors. (there may only be one......)

 

removed the pre cat o2 and no changes, additionally I’ve been noticing a chatter when it idles. I plan on reading out the engine coolant temp sensor wires as someone mentioned above, trying to figure out where c1 is (connector 1 on the pcm?) so I can read it out

 

I also noticed when I was looking at the pcm that it may have been replaced, it’s not mounted correctly, if the seller were to just slap another 1500’s pcm in this truck could it cause some of these issues? (I had a feeling the mileage was too low)

 

I think the cluster keeps track of mileage, though the PCM should know as well.

The replacement PCM would also have to be flashed to the correct vin, or abs, and srs lights would constantly be on. PO probably just got one from some mail order company, for whatever reason, and replaced it himself.

There should be a pic of which connectors are where in the service manual. (connector locations.....)

 

abs light constantly on, even if I try to flash the codes

 

What about the SRS lite? (air bag.)

2 or 4 wheel abs? Lots of interesting little problems can turn on the lite, and you need a decent reader to get abs codes.

 

air bag too, yeah my reader doesn’t do that

 

I got a few new things to add to think that the last seller replaced the PCM without flashing, borrowed a friends abs reader and found these codes..

63 shuttled reset switch concern
66 power relay short
84 mismatched VIN
37 rear sensor signal erratic
35 rear sensor circuit malfunction
78 base brake system incident