OK. Just come from the Chevy guys. They ran the scan tool only to find no codes! Strange since I had my CEL on for a while before going off of it's own accord & the fact that I was not able to engage the 4x4.

The guy pressed the 4x4 buttons a few times to try activate it but the lights just blinked back then, after a while, he got a code (C0387 I think he said) Said it simply meant "4x4 not working". I left a bit dissapointed with still no clue of what or where the problem is. On the way home, the Service 4wd light came on & all lights on the dash switch went off. I returned to the shop & restarted the truck . . . surprise! the lights wre working again & no service 4wd light. Even though I was in 2wd, only the 4hi button was blinking. We were all confused so I booked the truck in to be checked & quoted - Jan 21st nearest appointment, so no 4x4'ing this weekend. I could be in for anything up to 1000 bucks!

By the way, I've done a search on both this & the .net forum but could not find this code.

At the same time I met a guy who recently bought a Blazer (he was buying parts for his waterpump). Tells me he had the same problem & the dealer he bought from sent it out to got it fixed. I went to the car yard but they had no recollection of the sale. I had asked John to sign up here & on .net so hopefully I can check with him & get the details again.

 

I cant remember your other threads, but I take it you checked out the TCCM in the passenger kick panel?

I dont think the vacuum actuator or anything with the front axle trips the C-code.

 

When I press the switch I hear the clicking from the TCCM (pass side under dash).

 

C0387 - Unable to Complete Shift

I would definitely start by checking the connection at the TCCM. I am not sure if it is still located in the right side kick panel with the RHD and everything, but I guess start there.

 

Thanks Kyle. I'll check & make sure connections are clean. And yes the TCCM is in the pass kick panel.

Also, the guy in the shop had some TCCM's lying around so if cleaning does not work I'll swap overwith one of his. If it works it'll only cost me 180 bucks.

In swapping over will code need to be reset? Another thing - before I unplug the TCCM do I need to disconnect the battery? The Haynes book seems to require disconnection.

 

The code will go away on its own, but can be cleared by pulling the battery connection for 10-15 minutes. You may want to try that first as well and see if that influences your problem.

 

Thanks again Kyle. Wow this exchange is as good as a phone call.

 

Update: I went out intending to disconnect the battery & remembered the power drain on my battery so I decided at the same time to check the engine compartment light which was a suspect.
As I pulled on the wiring harness I noticedthe vacuum hose from the vacuum actuator (junction thing on the firewall at the back of the engine)had been rubbing on a hose fitting & was worn through. The one that heads down to & under the battery tray.So I rushed out & after visiting a number of suppliers found the same size pipe. Will replace first thing in the morning. Engine & sun too hot right now. Hope this solves my problem. Will have to start a vac pipe replacement program. LOL

 

Managed to replace the pipe this evening but still no luck.
I can now get a solid light on auto4wd & 2hi. but no action on 4hi or 4lo. I still hear the clicking on the TCCM but no clunk or whatever sound from the t/case.
I'm wondering now if the TCCM is okand maybe the problem is in the actuator thing under the battery. I'll see if I can get a used one & swap it out with mine. I'm not looking forward to it being the switch on the t/case as they want $675 for a reconditioned one.

 

Took the truck in on Tuesday & they've still got it.

They found the transfer case selector switch was defective & replaced it but still could not get any action.
They suspected that the selector shaft fork thingy inside was broken & the box needed opening to find out what & why.
They told me that as far as they were concerned the transfer case was a "mechanical breakdown" & I need to contact my insurers which I have now done.
The insurers have asked for a report on the internals before issueing a purchase order. If they're ok with that I'll be in for an excess of $350 instead of a bill for around $2000.
I am not optamistic about getting it back by tomorrow (Friday). Unfortunately Monday is a public holiday so I may have a long weekend withoutthe black beast.