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new pcm. hard downshift from 2nd to 1st at stops??

colindunn

colindunn

New member
put a new pcm in. dhp tuned. when im driving, go up to a stoplight or anything and under normal braking you feel it "bump" into first at around 6mph or so. feels more like just a harder shift i guess. now if i slow down as slow as i can, i dont feel it at all. and if im braking somewhat hard to a stop, i feel it even more. what is this and why? is it bad or normal? it didnt do this with my stock pcm.
 


Just a guess, but could probably be due to the increased transmission line pressure in the DHP tune.
 
does it matter since i do not have performance shift on my car so i cant enable it? also im not able to use my cruise control either. is that normal? not a big deal but wondering why
 
No...its not normal...they probably tuned it wrong...what year car was the PCM from? What year car is yours?
 


colindunn said:
whats not normal? the cruise control or downshifting or both?
Click to expand...

None of it actually... i have a DHP pcm on mine, other than intake its mostly stock and it doesnt do any of that, the shifts are firmer but i cant feel it downshift at a stop and everything on my car still works.... mines a 99gtp
 
okay. yeah mines a 2001. my tranny is fine. so the computer can actually cause that then with the tranny? i know the pcm is causing my cruise control to not work.
 
I sold Colin the pcm, nothing was done to it other than reflashed with the same file I have put on several other cars in the area. Not sure what is causing this, but I will take care of it Colin. You've got a PM.
 
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FWIW my 2001 you can feel the car bump into first when comming to a stop. Its been on the same trans flash for 4 years and I never worried about it. Trans still going strong
 
I'm going to send him a another pcm with a trans settings based off of my wife's tune's trans settings. I've never noticed anything other than perfect shifts in her car (stock trans) and her tune is completely custom tuned with HPtuners. The pcm he has now is all DHP 1.0.

His ABS and TC lights are both on, he says they have been on since he got the car but the cruise worked before. My GM service info says that cruise is disabled when either of the lights are active for more than 2 seconds. I seem to remember my cruise not working when my lights were on because of a bad wheel speed sensor. Can anyone verify?
 


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