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Discussion Starter · #1 ·
Gentlemen-
Forgive me as I haven't posted on here since it was the old board! I used to answer my share of electrical and mechanical questions for the newbies and now it's my turn to ask one... I swapped my 1996 2.7 from auto to manual back in early 2003 and haven't had a single reason to look back or mechanical problem with it since. Someone on here may still have the data sheet I compiled with parts that do and do not interchange as well as my writeup on the swap.

History:
I fudged the truck through inspection 2 years ago and now it's time for it again. NJ has cracked down and wants an OBDII scan and won't pass me if the MIL is on. Time for inspection so time to fix the truck... I show codes for shift solenoids A, B, and E as well as the P/N position switch (2 trip logic) and tranny temp sensor. All are understandable codes for the trans swap and as such I was going to dummy the sensors out with the proper value and wattage resistor. That won't cure the A and B codes though, because there's logic associated with them instead of a straight resistance check. Here's the twist: A few days ago I acquired and installed a computer from a 5 speed truck, same year, same engine. I should have known better thinking that would solve the problem...

Problem:
With the new M/T computer installed it throws the same (A/T) codes! In addition to that, the 'O/D Off' light flashes (didn't with the auto computer). What is interesting about this to me is that even though it's a 'manual' computer it still registers 'automatic' codes and recognizes them! Something, downstream of the ECM, tells it that the truck is 'supposed' to be an automatic. What is that part? Here are my ideas: P/N Position switch is still in place, possible offender. No clutch switch to enable the starter (always enabled due to constant 'N' position on P/N switch) Is there a separate ECM anywhere that an A/T truck would have and a manual wouldn't? I only know of the main ECM. Can anyone think of the differences in wiring from a manual to automatic truck besides the obvious trans related items? I'm particularly interested to know what wiring the manual truck has that the auto doesn't so I can replicate it.

I sincerely appreciate anyone who's read my long-winded post and has the knowledge and courtesy to respond. I'm stuck! Thank you!
 

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Have you look at the FSM? It will have both auto and manual wiring. With some Compearasion of the two, you should beable to find the difference. Here is the link for the FSM:
http://www.ncttora.com/fsm/index.html
Hope this helps. Best of luck. Keep us posted on what you find.
 

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Discussion Starter · #3 ·
Hello-
Thanks for the reply. I did check the manual and it shows that the pinout for every connector on the ECM is slightly different from manual to auto. I've just dummied out the sensors for now to get me through inspection then I'll see what else it takes to figure it out. At least I'll buy a little time. Thanks!

Greg
 

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bump to keep this thread alive. I'd like to know the outcome/solution
 

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Without lookig at the FSM the only thing I can think of is did you also remove the A/T ECU? If it's still wired in to the harness it will send signals to the ECM.

I'm not too hip on 96' but I believe there is an ECU for the ECT(Electronic Controlled Transmission) That should be disabled.

This also reinforces my theory that the ECM's are the same for A/T and M/T as far as the insides are concerned. I think the main difference is the California spec ECM's and Non Cali.

It just doesn't make sense from a manufacturing standpoint. It would cost twice as much to make two ECM's for the same year. It would be much cheaper to make the changes in the wiring harness.
 
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