limp mode
 

hi ,my 94 z28 does this,1,2,3,harsh then no o/d or lock up,then manual 3 and 2,then i turn it of and it does 1,2,3 same again,if i disconnect the battery its all ok ,kick and everything,then it will go back to limp,some times after 10 miles or 3 miles,or less.trans has 2000 miles since rebuild,scan said 3/2 down shift feed back fault,bell tested from pcm to pan ,ok,changed 3/2 solinoid,still same,new tps and map,by passed ignition as well,i have 5 volt ref on tps,and 0.65 throttle up,then 4.57 wot,engine not running,with it running its 0.66 at 1100 revs then 1,80 volts at wot,is this correct ?help ,i dont know what to do next,thanks

Re: limp mode
 

Seems that you may have the same problem as another member:

https://www.camaroz28.com/forums/sho...d.php?t=793300

Re: limp mode
 

By same thing do you mean you are still getting the same DTC84 for the 3-2 solenoid?

Re: limp mode
 

no, i havnt had it scanned since i changed solinoid,i got stuck into thinking it was the ignition switch,at the moment i cant under stand tps volts i believe tps can send it to limp

Re: limp mode
 

I highly suggest anytime you have a problem, that scanned faults be the first thing you attack. Then go after the symptoms that have no faults. Not the other way around. You should have a way to scan it yourself.

Re: limp mode
 

thanks,can you just confirm should tps volts be the same with engine running ,volts are to spec not running

Re: limp mode
 

Yes use the KOEO reading.

Re: limp mode
 

o.k tps volts ok,i have been looking at this trans problem for some time now,i have read the replys on brandon 94 lt1, and the pcm wires volts checks were all ok, but i have opened the harness near to trans filler tube and checked volts on pink wires,the pink feed to trans has always got 12 volts can you confirm the correct volts on the other pink wire,my chilton manual shows it returns on red/black, i havent checked this,should i get 12 volts between these two or to ground? i have had trans plug out seems ok thanks

Re: limp mode
 

You need to reset the PCM and rescan it after having taken it for a ride

Re: limp mode
 

o.k, i have got to buy a scanner as no body near me has obd1,its going to cost less to buy an auto x ray,my battery is,12.12,then 11.52 cranking and 14.58 engine running,is there a way to eliminate shift solinoids a and b ,they were replaced at rebuild,i will scan and be in touch ,thanks ,scott

Re: limp mode
 

i have now got tts data scan and it works great,this is what i have found,1st cleared codes,them start engine 5 seconds latter code84, then i drive ,it then shows in trans status bits chart ,on bottom line which refers to 3/2 downshift open circuit,the red and green squares flash alternating very fast,the car then shifts normaly for about 2 miles then stuck in 3.then i switch ignition,when i switch back on it gives a code51,disscon battery and it does it all again,also the tcc control open line flashes green red about every second,i think the red/green indicates the solinoid is opening and closing very fast,it does this all the time ,all through 1,2,3,4 ,i have repeated this about 6 times with same results,by the way the code 84 comes up when its still in park,hope someone can help.thanks

Re: limp mode
 

Let me save you some time, find a pcm that's the same as yours, swap it. From what your saying, it's just like what I was able to compile on my car. You need a pcm. Lol 3-2 shift solenoid is the tell tale here. I replaced the A,B, 3-2, barometric pressure manifold. And all along it was the pcm. Mine threw the 3-2 and then the computer would go nuts and then it was only 3rd starts with a manual pulldown to second. Another possibility is your pigdtail going to the tranny. Check it for tranny fluid seeping into the plug, also even though it's a pain to do, use an inspection mirror and check the plug on the tranny for problems with pin alignment. Also check the pins of the harness itself. So scan it and find out that u have a 3-2 problem that goes away after a reset, might get a good series of upshifts and the u go into limp. It's your pcm. Welcome to the club, oh does the car by chance do anything else? Listen to the overall tone of the exhaust when u fire it up, and then when it goes to limp. My car also got terrible fuel milage and then it started to run rich, I attributed that to a header leak, it was paertly due to that, but the vast majority was due to the pcm taking a nose dive. Anything else just yell. Hope this helps, god knows it was frustrating to chase my tail all that time. Hope u won't have to. And the really hard shifts, that's another sign also.

Re: limp mode
 

o.k sorry i didnt reply i havent loged because nobody was replying, yes i have checked it all out i have a remanufactered pcm on the way,i do get a change in tone on the engine so i just hope this sorts it out thanks for the help,the car is great apart from this ,i think i would get a 6 spd next time,scott

Re: limp mode
 

Hey its cool. I just had the same problem with my formula. The fun part was running all the connections down and always finding nothing new, plus I got to know the internals of my 4l60E pretty well. I've done as much digging as I can, and the 94-95 yearmake pcm is very reliable. However since having my problem, and the help of some friends here on the forum, and some off, I found that my pcm went rogue. But the good part, if there is a good part, is that the symptoms are pretty much all alike. The bad part is that its looking like more and more 94 pcm's are starting to do this. I've helped 4 people get their F-bodys back on the road, a couple of the cars had been stored for over a year because the dealerships here were unable to diagnose the issue(I had the same outcome). So Idk, maybe its just the flu for 94 F-body pcm's????

Re: limp mode
 

Hey scott, did the PCM fix your problem like it did brandons?

My 95 Z has been acting exactly like yours for the last few weeks. I've replaced the VSS, 1-2 and 2-3 shift solenoids, as well as a fluid / filter change but nothing. Trans shop said that it sounds like a bad 3-2 but it's not throwing any codes.

I have a forum on ls1lt1.com.. http://www.ls1lt1.com/forum/automati...tml#post413554

trans fluid has seeped into the large pin connector on the top of the transmission, would that cause this? I had a bad disconnected ground to the PCM (on the side of the engine block) that i found about a week ago, could the PCM be fried?