• Welcome to The Truck Stop! We see you haven't REGISTERED yet.

    Your truck knowledge is missing!
    • Registration is FREE , all we need is your birthday and email. (We don't share ANY data with ANYONE)
    • We have tons of knowledge here for your diesel truck!
    • Post your own topics and reply to existing threads to help others out!
    • NO ADS! The site is fully functional and ad free!
    CLICK HERE TO REGISTER!

    Problems registering? Click here to contact us!

    Already registered, but need a PASSWORD RESET? CLICK HERE TO RESET YOUR PASSWORD!

WTF is this????

Michaeljp86

EVIL GENIUS
Messages
1,615
Reaction score
14
Location
MICHIGAN
Is this the computer that controls the transmission? I swapped computers with the one in my friends truck but I still have the same codes and still cant clear them. I checked for codes as soon as I plugged in the new computer, never ran the track or even turned the key before i checked the codes. If this isnt the transmission computer then where is it? This is the one that was behind the glove box.
 

Attachments

  • DSC00531.jpg
    DSC00531.jpg
    73.3 KB · Views: 52
On the '92-93's there is only 1 PCM computer and it's behind the dash like yours is. The issue with the codes is very strange or both PCM's are seeing the same issues.
Don
 
If you take off the back plate (its a torx) there is a chip inside that can be changed out. Here is a pic of the computer that came with my new engine. Look on the side down low there is a trap door..... Sorry i dont have a pic of it opened up....
 

Attachments

  • Pics.  3 08 2009 015.jpg
    Pics. 3 08 2009 015.jpg
    97.9 KB · Views: 24
The chip is for the motor, in a 92 or 93, the motor is mechanical, the puter is only to control the tranny. That is why no chip
 
Mikes is only a TCM, whereas in 94 we have PCMs. Now there were chips in TCMs, although my reference only shows it for some of the 2500 and 3500s.

The chip is that big blue thing in the picture. It comes out and can be swapped.

What is the 4 letter code on that blue chip.
 
I dont see a chip, I think only the obd2 had a chip

actuallu obd2 vehicles doesn't have chips, they have re programmable flash memory which is soldered to circuit board, obd1 ecm:s have chip, but so is in your tcm too, it is that blue box in your pic. it doesn't control engine, but there is calibration information for transmission like gear changing speeds, torque converter lock up and release speeds etc..
 
HAve you checked the circuits affected by the codes yet? *DTC 59 - Transmission Fluid Temp Circuit High and *DTC 81 - 2-3 Shift Solenoid Circuit Fault. Yes the blue part in the upper right of the PCM is the chip. It controls the tranny shift speeds, line pressure, and shift timing as well as glow time and advanced timing solonoid for the engine. Both of the codes you list can be thrown without starting the engine and would set almost immediatley after turning the key on. Is the tranny original? If so sounds like you need to replace the TCM plug and matching connector on the harness side to the updated ones. 92-93 have a known issue with the original plug having MANY problems like this and others problems as well. To upgrade you will need the internal and external wiring harness's for the tranny. Both can be had at GM and many online retailers as well as this site has them for what looks like a good price.

http://www.transmissioncenter.net/4l80e.htm

If you plug on your tranny doesn't look like this one, replace it with the new one.
HPIM1634.JPG
 
I was told by the guy I got the truck from that the transmission was rebuilt 1 year before he got it.

Mine looks somewhat like the one in the picture, did the stock plug look like that? I think the inside of mine is white not green.
 
The older plug is very similiar, but it will have a bolt through the center of it to hold it in place.
 
The older plug is very similiar, but it will have a bolt through the center of it to hold it in place.

I cant remember but I think mine did have a bolt. I'll have a look tomorrow, I have to park it in teh driveway because of the rain. The 2wd isnt any fun in the mud.
 
the older style plugs have a bad tendency to leak inside the plug itself. the seal they used was not a waterproof design, water resistant at best.
 
Back
Top