OldJudge

I have california origin 1993 jeep grand ltd with a 42RE autotrans and it seems to be stuck in default 3rd gear.

History:
1. fuel pump gets no signal from relay
2. PCM is bad
3. Tried to get it home from Montreal
4. Lost power, gauges turned off, tranny dropped in a low gear - no restart
5. broke down going uphill - Thank you AAA for the 103 mile tow home
6. pcm recieved via Auto Computer exchange - plugged it in
7. fuel pump worked, it started right up - thrilled!
8. transmission would NOT shift
9. no previous transmission problems either despite 223,500 miles on it
10. o/d button does not work b/c it seems to be "Default"

with a breakdown, pcm repair, and a default code - assuming the transmission is still okay - is there a way to RESET a DEFAULT CODE?

I know the 42RE is electronically controlled - the PCM is the exact chip of the original so it is the correct computer... is there a way to reset the TCM or the solenoid or something.

How do i get my jeep out of Default 3rd

thank you to anyone who can help!

-Anton

mike37

unplug the TCU its under the dash right under the glove box
then you can shift it manually

ol"blue

Check in here, there might be something that will help.>>--> 93ZJ Secc 21 Transmissions and Transfer Cases
And Welcome to CF.
Dan

ol"blue

I found this info.>>->http://www.asashop.org/autoinc/july98/techtips.htm
Check the codes as stated here using the OD light.

mike37

I found this TSBal Service Bulletinsechnical Service Bulletins

http://www.wjjeeps.com/tsb/tsb_wg_2100908.pdf

http://www.wjjeeps.com/tsb.htm

ol"blue

Great finds Mike, but those don't apply to his '93.
Dan

mike37

guess not thought it said 93 when I read it

OldJudge

Gentlemen - thank you - I just had it scanned today with another pcm and it "does not see the trans" it is the OEM #56027813 and i've tried OEM 56027285 pcm and ...488. but it seems that the 1993.3 with 42re only wants 56027813pcm - which i have - but its in really bad shape inside and the "Auto Computer exchange" cannot fix the fuel pump circuit (the original problem) after 2 attempts?!!? i don't see why its so hard? ...but lets say the computer OEM #56027285 which is currently running the fuel pump fine (but not the transmission) actually can see the transmission and I'm not 100% sure that the 56027285 is defective in seeing the trans - it might and maybe the problem is in the transmission electrical circuit (although - the problem would have had to been caused when the original 813 pcm died)

my brain is fried on this 93.3 42re JGC - lol ...ahh!

i'm ready to just buy a new jeep - like the one with the nice diesel engine mmM... yeah ... lol - except for that fact that i don't like when i can't fix a perfect jeep because i don't know the electrical circuits... and... if i could, i would take the pcm to computer PC shop have the geeks make a new circuit on my original PCM for the fuel pump... but the circuit diagrams are like TOP SECRET chrysler files only a psychic can access.

thanks for the input on the output... };-.)>

ol"blue

If it were me I would get a reman PCM from the dealer and start enjoying the truck. You happen to have the two ZJ model years that seem to have lots of comp. issues. The first and the last. I wonder why that is?
If you go on NAGCA http://www.nagca.com/forum/index.php
you might be able to locate a used PCM with the #s that you need. Good luck.
Dan

mike37

unplug the trany from the PCM right at the drivers side of the trans
and see if it shifts manually

OldJudge

It does shift manually - 1-2, 2-3... but it stops at 3. there is no 3-4

and this is the interesting question for me about the "default 3rd" - I didn't even know the 42re trans had a default until now.

**The Original OEM#56027813 has been rebuilt twice now and I just sent it back to "Auto Computer Exchange" for a 3rd time. They have failed to fix the fuel pump circuit on the pcm twice - and twice is a lot unless they really puzzled over my 93... they might be looking at the 93 repair diagram and not realizing that there is a 93.3 or 94 diagram - they could be fixing the wrong circuit not knowing its not the fuel pump - which i explained in a letter to them for a 2nd time! :-S

lol - (and thats a crazed LOL)

OldJudge

We'll see - i'm going to scout out some used pcm's from the yard - hope to find an ...813

if that fails - and i still have a pcm that doesn't see the trans on the scanner... then... i dunno - i'll have to go to a dealership and say make my transmission and fuel pump run at the same time.

the **** of it is... the 93 is perfect - everything on it even the tires - but its worth 2,000$ ish and lets say i put a new transmission and pcm in well thats 1500 for the trans and Torque converter and 700 for a NEW computer and LOL - well for 2200$ i could put that down on one of those nice diesels - lol - sigh ...but i won't.

OldJudge

and i'm to attached to the jeep - its like getting in a fight then having a beer with the guy you fought - thats how i see the jeeps - they're like a part of the family... i mean i even feel like i have a soft spot for these things... lol - we grew up together.

enough said -

thank you for the time and information - Cherokee Forum is great and i will recommend it for other jeepers.

mike37

what state are you in

ol"blue

As a stop-gap measure you could use the PCM that makes the trans function properly and then just run a separate fused power line for the fuel pump. JMO
Dan