The nature of electronic failures.....

With the code for TCC shorted, think I would check local junkyards, and see if they have a PCM for ya.

 

May be a quick and cheapest way to determine if that's it or not for sure. But finding one for a 94 is what's gonna be the challenge.

 

Yeah, they are getting to be a bit on the Rare side..... Maybe Car-Part.com can source one for ya.

 

What are the odds the converter itself is going bad? I was just told that normally when you get the 37 code it means the converter is going and its telling the pcm not to send the ground signal to the lock up. How would I know for sure? I done some more testing today and if I unplugged the solenoid and test the wires with the key on the middle wire has 12v as it should, the overdrive wire and the TCC wire are both grounded. But when I plug the solenoid back in then the overdrive wire and the tcc wire turn to 12v hot wires and dont ground out.

 

Neither of the other wires should go to ground with ignition off, or any other time, other than when the PCM wants TCC, or O/D. PCM controls the ground side of the circuit to control the solenoids. The other two wires in the connector should show open while testing.

 

Okay, thank you. Im hoping I just found what's wrong with it earlier, do these transmitransmissions need the temp sensor for the TCC to function properly?

 

According to theory........ The PCM wants trans temp at 108 or above in order to engage TCC or O/D. In my experience, that simply isn't the case. I really don't think my trans is making it north of 100 degrees after being driven less than half a mile, on a sub-zero day, but, I still get TCC and O/D before I even make it to pavement. (about two miles away.) I don't warm up the truck in winter. It's parked in the garage, so, no scraping required. I just jump in, and go.

That said.... The PCM DOES care if the trans gets too hot. Above some temp that I can't recall right now, it will turn on the trans temp idiot light in the cluster, and disable O/D, (and the O/D Off light will come on.)

Of course, all of that only applies to the 96 and newer transmissions. On the 95 and older ones, the trans temp sensor was external, and only came as part of one of the 'heavy duty/towing/plow' packages. So, on a fair few of the older trucks, the PCM simply doesn't care about trans temp, as more often than not, it doesn't even know what it is.

 

Well my truck is supposed to have one and doesn't, could that be what is causing my tcc not to engage?

 

If there is a sensor, it *should* be in the trans line at the front of the trans, very close to the trans. Is there even a fitting there for it? Should be within 6 inches of the trans.

Are you getting a code for trans temp?

 

I read in the manual you told me to download that trans fluid temp sensor plays part in the functionality of the TCC, and my truck has the plug for one that's just hanging down by the transmission and the portion of line where the bung would've been for the sensor has been cut out of the line and replaced with compression fittings. It somewhat explains why my truck keeps burning up transmissions... when I was daily driving the truck a few years back I had the trans rebuilt 4 times in 4 years bc it was burning up.