Chevy code co321

[dlbleak]

my 06 z71 shows the ‘service 4wd’ message. Almost all of the info on the web and YouTube is info for the co327 code. I already replaced the push button component on the dash with no luck. I’ve seen videos where the guy replaced all four components and it still ended up being a short though. Has anyone gotten the 321 code and what was your fix? Thanks

 

[NightShade]

https://www.justanswer.com/chevy/4545k-code-c0321-service-4wd-light-will-not.html

https://www.tahoeyukonforum.com/threads/service-4wd-c0321-code.94059/

So check the tccm which sounds like it is in the kick panel and check the solenoid.

May also try clearing the codes and see if it will try to function or immediately come back.

 

[dlbleak]

I’ve been all over the net and YouTube. The 321 code description it pretty vague. It more or less says you have a short someplace. The 327 code is almost always the encoder motor. I’m not good with troubleshooting electrics, I’m a nuts and bolts guy!

 

[NightShade]

Most of the times it's in the connectors or right next to them. I had an issue with the camshaft position sensor in my 4.7l Replaced it with a cheapo unit and it still had issues. Started to do some testing and found it had a broken wire right next to the connector. Rebuilt the connector and extended the lines and it was better. Found out that the aftermarket sensors are not as sensitive as they should be for that purpose so bought an OEM one and it has ran perfectly ever since.

Find a wiring manual and pull the connector, then test the connections for which one is potentially grounded but should not be. But honestly if it's a short it is probably not in the wiring but the devices. The TCCM would then likely be the culprit. But you can still test each end by looking up the wiring diagrams pull battery and check the tccm for something that is grounded but should not be. Same goes for the other connection points. A multimeter is worth it's weight in gold when it comes to potential electrical issues.

 

[NightShade]

And if you want some help let me know. You are not far away from me anyway I will give you a hand.

 

[dirtrider73068]

It could be simple as a bad ground or corroded connector if water or moisture got into it. I was a mod on a truck forum group but lately can't get on the website was shut down with out notice and alot of good guys in there loved helping those work on their trucks. Its going to be a pain but it sounds like its going to be tracing wire time, get a diagram a true one that tells what colors are what and follow wires, see if one is shorting to ground or a bad connection somewhere, even a wire that has some how gotten pinched or even knicked which again allows moisture to enter the wore and corrode it causing unneeded resistance and in todays worlds of touchy electronic systems in vehicles won't take much to set off a code.