4L80E 1993 6.2 no 1-2 shift

[jdla140]

Have you checked codes by just shorting out the correct pins on the obd1 connector? I don't know the exact symptoms on the 4l80e equipped mechanical diesels, but there is a chance you have a bad engine speed sensor. It caused all sorts of whacky stuff on my 93. Mine gave a code that I could only reference back to cruise control switch, but normally you should get a code 12 with the engine not running, if you get a code 12 with the engine running you probably have a bad ESS.

 

[Blue93cube]

Do they still service the 1993 plug? All of the case side kits I saw have a different pin setup that what’s on the truck currently and notes kept coming up about an updated plug. I don’t mind splicing in new truck side wiring if I have to.

Common issue but at least you know you dont have a mechanical problem in the case that would require overhaul.

Replace the transmission internal harness; many of them leak through the conmector and I never reuse those harnesses when building any trans that uses one...hopefully your external harness that comes from the pcm to the transmission isnt compromised...

 

[Blue93cube]

I haven’t tried the jumper since I replaced tcm, I thought ESS failure would throw SES? I really hope that’s not it given the prices of that piece..

Have you checked codes by just shorting out the correct pins on the obd1 connector? I don't know the exact symptoms on the 4l80e equipped mechanical diesels, but there is a chance you have a bad engine speed sensor. It caused all sorts of whacky stuff on my 93. Mine gave a code that I could only reference back to cruise control switch, but normally you should get a code 12 with the engine not running, if you get a code 12 with the engine running you probably have a bad ESS.

 

[Blue93cube]

Do they still service the 1993 plug? All of the case side kits I saw have a different pin setup that what’s on the truck currently and notes kept coming up about an updated plug. I don’t mind splicing in new truck side wiring if I have to.

Following up on early versus updated connector. Anyone know?