Backstory first. this may get confusing.. back in november i was tuning my ve tables with hp tuners logging trips to work and back and then changing tables not really messing with anything else in tune. Well on thanksgiving day my gf and i were in my car headed to my dads house for dinner when my front wheel fell off, yeah thats right fell off! Lol we wont get into that but long story short i put the car in my garage to fix the damage done by this and then since the weather was getting colder i decided to just leave it in the garage and do some interior work over winter. Now here is my issue.. i recently got the car back together and decided to get it out and drive a little. I took it on about a 20 min drive and everything seemed ok but i still had the maf unplugged from the ve tuning. Well since i wasnt too far into the tuning i decided to temporarily reflash the pcm with the stock tune and plug the maf back up until i do some other mods i have planned.. i downloaded the newest version of hptuners which i had never used before and went to flash the pcm i got an error message about failed connectiin the first attempt but tried again and it worked (or seemed to) but now when i take off from a stop my car feels like its taking off in 3rd gear and then shifts to od.. if i manually select 2nd gear it seems to work but if i select 1st it still feels like 2nd.. everything ive read says this is caused by a faulty shift solenoid but can it be coincidence that it happened right after flashing the pcm? Is it possible i bricked the pcm? Or could it be something that happened while the car has been in the garage over the past few months? How do i determine what is wrong?

Sorry this is so long, and if im posting in the wrong forum feel free to move... any all ideas welcome.

 

Are you doing the "write entire tune" Long or "write short tune" short to the PCM? You should be using the short one. But since your having issues now it would probably be a good idea to load up a stock tune and do an entire rewrite since you already are having issues. I have ordered an extra PCM for tuning issues (and smog ) from ebay for $90 as a backup PCM. The seller even loads up your VIN number... probably a good idea.

 

Ive always used "write calibration" with no issues, but i did try writing the stock bin with "write entire" after the problem started. Didnt make a difference. Do u think its a pcm problem tho? Or just coincidence a solenoid died at same time?.. not throwing any codes btw, i read that a blown fuse would cause same symptoms but throw codes, and ive checked every fuse in the car with a meter just to be sure they are good

 

ah ok good, that's what I was asking. as far as the solenoid dying at the same time... I seriously doubt that would happen. hmm though I don't see any other way to figure this issue out without having another PCM to test with. I'm thinking the PCM is possibly damaged, but that's just my thought.

 

Well luckily me and my gf both have 98 TAs so i guess i could swap my pcm into her car and see if the issue follows or vice versa.. what exactly would i have to do to make my pcm work in her car? Just bolt it in and then write her vin to it?

 

You should be able to just drop it in and go. The BCM handles the VATS system.

 

Well.. I put the suspect pcm from my car in my girlfriend's car today and it works fine.. which is good to know my pcm is ok, but i was kinda hoping we had it solved... the search continues, i think i will try swapping the 1/2 and 3/4 solenoids around next and see if i lose 3rd / 4th and gain 1st / 2nd.. if this dont work, what else could it be?

 

Well good thing you have another bird to play with, sounds like she is a keeper . hopefully just a failed solenoid. GL, make sure to post your results after you get into your trans.

 

Havent swapped solenoids yet, probably try it this weekend but i did remember something else. Maybe unrelated but after the wheel mishap i mentioned in original post i changed my front lug studs to arp studs and forgot to plug the speeds sensors back in when i put the hubs back on.. when i first got my car out of the garage my "abs inop" light was on and i figured out what it was pretty quick, but now that i think about it the trans problem started right after i plugged those sensors back in.

 

Check for any DTC's and clear them if found. It sounds like your tranny may be in limp mode. If so, something is triggering it.

 

Not throwing any codes, but ive been reading about limpmode and thinking that too

 

I'm going to move your thread over to the A4 forum where you're much more likely to get fresh ideas.

I've had limp mode with no DTC's both with a stock converter and with my SS3600. Having a dealer do an update reflash solved the first, and tuning out some error codes solved the latter.

What year is your car?

 

Thanks revgto, wasnt sure where to post bc i wasnt sure what was going on.. car is a 98

 

If the 2-3 shift solenoid was stuck...It would take off in 4th, Shift to 3rd, Then shift back to 4th.

What is the PCM commanding the shift solenoids to do?

 

I'll check as soon as i get the chance. I really haven't got too far into diagnosing yet, other than testing my pcm in a different car.. i've mostly been reading and trying to get opinions on where to look so far.. i do have a question about limp mode tho, ive been reading all the possible causes and even though it wouldnt make much sense, can the airbag induce limp mode? Reason i ask is b/c during all the interior work i took the stock wheel and airbag out and replaced with a grant wheel, im going to wire in a resistor to turn off the airbag light in the dash but havent done that yet.

 

I keep thinking about the front wheel speed sensors too, car was ok with them unplugged and then problem started when i plugged them in.. was there anything i shouldve done after plugging them back in? Or could they be bad and causing this? I may try unplugging them again and see what happens

 

ABS wheel speed sensors do not effect transmission operation.

 

I have no knowledge that when the computer sees "airbag deployed" it commands limp mode, but it wouldn't surprise me if that was the case. Limp mode seems to be commanded in a variety of circumstances when the car is perceived to be in an abnormal operational state.

 

Airbag/SRS is 100% stand alone on 4th gen F-bodies.

 

. I got the resistor in light is out, still in limp mode if indeed that is whats going, still no codes.. ive got a couple solenoids ordered, maybe thats it.. ill kerp u all posted.. any more ideas in the meantime tho id love to hear them