DuoDS

Putting a TH400 in my project and would like to know what I can do to keep the SES light from being lit all the time because of no speed sensor and/or transmission connections. I would like to use the SES light to alert me to trouble with my engine / sensors / tune.

Project is a custom sand rail by the way, with a 98 LS1. PCM has been flashed and wiring harness rebuilt, but I think the guy I had do it didn't undertand where I was going or exactly what I wanted to do. Heck, I don't even know if you can flash the PCM with a transmission "delete".

If I just need to cap the wires and deal with the SES, that is fine, but it would be nice for it to function "correctly" and warn me to trouble.

Thanks for any advice in advance.

WeeWolf

iTrader: (16)

The tuner should be able to delete trans and if not can set all the trans codes to not trip the light.

NastyC6

iTrader: (77)

The computer needs to see movement in the vehicle.this is what i use.

http://www.dakotadigital.com/index.c...rod/prd109.htm

H-FIELD

The way I understand it is the computer needs to be programmed if it is being used in front of a Manual transmission to make it work with a th350 or th400. I'm using a TH350 but I lucky and got the engine from a manual car so I hope to be good with the tuning in that aspect.

gofastwclass

iTrader: (2)

Yes, the computer needs to know when the vehicle is moving - it doesn't need to be completely accurate but it needs to know - especially in a manual transmission vehicle. Part of the logic of the tune requires this and can not be "turned off."

I would bet you have experienced some intermittent surging, low idle or occasional stalling on deceleration. Having the VSS hooked up will eliminate these issues. I would say if you haven't experienced at least one of these symptoms you are in the extreme minority and should buy a lottery ticket. At $30 the DD box is a good investment.

DuoDS

Thanks for this information, this is exactly what I need. Exactly how do you hook up this speed sender to the PCM?

jkade72

iTrader: (23)

The wiring harness had a plug with a yellow and purple wire that you would hook this up to or at least that was the color on my 98 harness.

DuoDS

Thanks, I have one on order. I will let you know how it works out.

texas82blazer

I have a th350 behind my 5.3 just had the tuner turn off all the trans codes and used the dd box it installs easily just screw it on where the speedo cable hooks up. I think it was a purple and yellow wire on mine as well check out lt1swap he has all the wiring diagrams on his site for the diff years.

MeanYellowZ

iTrader: (19)

Hooking up the VSS is a good idea as the PCM uses it for a few functions as stated above. Now with that said, I have done a handful of swaps with no VSS and my daily driver truck doesn't have the VSS hooked up and it can be programmed out as far as a check engine light and with some proper adjustments I have had no issues related to not having the VSS, although I still don't recommend it.