I have a 1996 full size blazer thats showing a check engine code p1864 from what iv read it may be caused by a soleniod located on the tranny does hane one know how to check remove or test this soleniod? Or have a photo of what it looks like so i can get a place to start.

 

The 4L60e viewed from the bottom with the oil pan and filter off:


p1864 is the TCC Enable Solenoid - right hand side, labelled as 'lock-up solenoid (in pump)'

fyi - this isn't my pic - just a google - the part (mis)labelled 'Manual valve position switch' is actually a collection of pressure sensors to tell the computer what the transmission is doing, manually selected gear or not

 

Solenoid looks like this when removed:

 

Thanks for the photos do you have to remove/replace the PMW in order to get at the TCC soleniod? Any body have the steps required to replace the TCC i have an idea but keep reading different instructions on the internet.........

 

I seem to recall that you do have to remove it - pull the clip holding the PWM in(slot to the left of the part) and gently slide the PWM out - if you're very lucky it'll come all the way out and you can set it someplace clean, it's been a while since i was in mine and i can't remember if it slides right out or just enough to get at the bolt under it. once the two bolts on either side of the TCC are out and the wires are unplugged pull the TCC straight down out of the hole. The new TCC *should* have the right connector on it and o-ring installed. put it all back together fill 'er up and hope to hell the computer knew what it was talking about!

 

So i replaced the TCC soleniod and i am getting the same code from the computer. The blazer is also in limp mode. I Dont know were to go from here and could really use some advice The code is p1864 tcc enable soleniod circuit

 

ah - erm. (been away for a while) - beyond replacing the part.... I guess you'd be into wiring harness issues, assuming the solenoid circuit really is at fault. A transmission shop 'should' know what other issues might cause the TCC to ghost as the problem. My experience is largely with the physical take 'em apart and put it back together stuff. If it were me I'd darken the door of a proper trans shop and fish for some info - tell 'em what its doing, what you've done etc..... I'm trying to figure a way to to find out if power's actually getting to the solenoid but nothings really coming to mind..... it needs to have the pan on to run and the pan off to get at the wires....

You could I suppose try first to use a multimeter set to ohms to check between the wiring connector on the top of the transmission and the connections on the new TCC solenoid. Pin connections are detailed HERE fairly clear and concise - its the page for a megasquirt expansion but it does show which component links to which pin on the case.

I'd be very surprised if the wires have failed inside the case, but stranger things have happened.... again, a good trans shop should have some ideas - the issue sounds very electrical and all those parts are accessible with the trans in place so you shouldn't have to pay them to drop it out at least.

 

I was unable to read any power up top at the ECM connector terminal 10(brown wire?), i replaced the wire tan/Black by running a wire directly down to the tranmission and connecting it to the tan/black wire and splicing to the brown wire at the ECM, I was then able get voltage to the terminal end (10). I pluged the end back into the ECM started the blazer and got the same check enging code p1864. Is thier something coming off the tan/black wire other than TCC that would set off the check engine and pervent me from bypassing the tan/brown wire in the harness. Could the ABS system be setting the code off, abs light is on. I checked the TCC with a jumper wire and can hear it click so its working,,,,,,,,,,,,,,

 

I cut the old wire down at the tranmission tan/black and ran a wire directly from the tranmission up to the ECM and spliced it into terminal ten brown wire. i then checked it with a light up circuit tester and there was voltage at the end of the connector( brown wire). I checked across the pink and tan/black down at the tranmission prior to runing the the wire to make sure the power was coming though the solenoid. i believe the soleniod is working i can hear it click with the pink connected and running the tan/ brown to ground. not being the best at this i originally cut the tan wire up at the connector thinking it was termianl 10 realized i was worng and spiced it back together. Started the engine and am still getting the same check engine code.........I have no idea were to go from here the soleniod is working the wires are fine but the check light keeps coming on p1864