torque converter stuck on

[hammer2]

MIL recently came on (2000 grand prix) comes on intermittantly. the car was very jerky, especially when shifting. took car to autozone and read obd II code. gave me error PO742 Torque Converter Circuit Stuck On. Makes sense given symptoms. So does anyone know how hard to change solenoid on this particular car? Got under the car and couldn't find anything. There are 2 wire connectors near the linkage. Is the smaller one for torque converter. I may pull the plug on it for the time being. had same problem on my 87 somerset regal. It would stall when I stopped due to converter being locked up. I just unplugged circuit and actually gas mileage didn't seem to change?

Thanks
bill

[GTP Dad]

Don't unplug anything. The transmission in your current vehicle is much different than the one in your 87. The 87 had a plug just for the TCC solenoid but the 2000 does not have this plug. You must go inside the transmission to change the solenoid and there is no way to disconnect it.

[BNaylor]

Originally Posted by hammer2

MIL recently came on (2000 grand prix) comes on intermittantly. the car was very jerky, especially when shifting. took car to autozone and read obd II code. gave me error PO742 Torque Converter Circuit Stuck On. Makes sense given symptoms. So does anyone know how hard to change solenoid on this particular car? Got under the car and couldn't find anything. There are 2 wire connectors near the linkage. Is the smaller one for torque converter. I may pull the plug on it for the time being. had same problem on my 87 somerset regal. It would stall when I stopped due to converter being locked up. I just unplugged circuit and actually gas mileage didn't seem to change?

Thanks
bill

I agree with GTP Dad. All commands and signals from the ECU/PCM get to the 4T65E tranny via a GM 25 way plug. Its located on the driver's side of the side cover assembly (top). You cannot disconnect this plug without disabling all key tranny functions.

Your TCC PWM solenoid is probably defective. Its located under the side cover assembly and is typically not a DIY job. Tranny shops will charge around up to $500 to replace it.

In the interim you could add some tranny additive such as Lubegard and see if the solenoid unsticks. You've got nothing to lose at this point.

Good luck!




Thrasher CAI, DHP v1.0 PCM,
3.25 SC pulley, CAIT GMAF, Hi-Flow CAT,
u-bend delete, 160 TS, TB spacer,
MSD 8.5mm wires, Autolite 104 Spark Plugs,
Goodyear Gatorback Serp. & SC Belt,
Nitto NT555R Drag Radials

[hammer2]

Thanks all. Have to like technology advances. Old one-if goes bad just unplug it. New one- no way to unplug it and need a shop to to it! Hell, I don't think I could change the 3 rear plugs on this car. My arms aren't long enough! I had to be contorsionist to change the blower motor resistor. The days of DIY soon will be gone.
Bill

[hammer2]

actually went out and looked under hood and from underneath again. I see the large connector that a previous poster mentioned. But there are two other connecters, like I mentioned before. They are located right near the linkage. One is a flat 6 wire, the other is sort of square and has 4 wires. What are these for?
thanks
bill

[BNaylor]

Originally Posted by hammer2

actually went out and looked under hood and from underneath again. I see the large connector that a previous poster mentioned. But there are two other connecters, like I mentioned before. They are located right near the linkage. One is a flat 6 wire, the other is sort of square and has 4 wires. What are these for?
thanks
bill

Those connectors are for shift linkage only, etc.

The TCC lock and unlock commands go through the 25 way connector.

Tranny side (jack):
Lockup=pin 4
TCC release=pin 18

Case Connector Side (plug):
Lockup=pin T
TCC release=pin V

The wires should be color coded purple and brown.

There is a GM TSB out on certain year model 4T65E trannies for TCC related problems. It recommends disconnecting the 25 way plug totally and then re-connecting. You can give it a try but the odds that it will fix the problem are slim. Good luck!





Thrasher CAI, DHP v1.0 PCM,
3.25 SC pulley, CAIT GMAF, Hi-Flow CAT,
u-bend delete, 160 TS, TB spacer,
MSD 8.5mm wires, Autolite 104 Spark Plugs,
Goodyear Gatorback Serp. & SC Belt,
Nitto NT555R Drag Radials

[bens99gtp]

the plugs you are questioning are for the neutral saftey switch. they tell the computer what gear you have selcted and also the small connector has the wire that comes from you ignition switch to the starter so un plug either one will cause your car not to start. i agree the most common problem in the TCC solenoid. But i would also spend the 50 bucks and replace the EPC as well. If the EPC ( which controls the pressure in the transmission) is not working low fluid pressure will casue slow soft shifts and the TCC to actualy slip more than the computer want it to which in turn can cause it max pressure out making shifting and application very hard. This extra pressure can then cause the releif part of the TCC solenoid to stick not allowing the fluid pressure to escape so when the car shifts into 2nd gear or higher the TCC is already on causing a very jerky shift and slugish acceleration and sometimes cause hardpart failure when going into 4th gear when it shift real hard. My sujetion from an ASE master tech is replace all the solenoids and switches in the side cover of the transmission. the EPC is like 50 buck and the shift solenoids are like 25 each and tcc is a touch more. There is also a FPS looks like a flat board all these go bad all the time spend the few extra bucks and replace them all at one time. givenm the fact the cradle has to come down to do all this why would you want to pay or do it twice seening it takes me about 3 hours to do it on a rack and i have done hundreds or these. I also recomend to my customer installing a light shift kit as sold on ZZPerformance. www.zzperformance.com its 30 bucks the reason i sujects this is not to make the trans shift harder but quicker this is super easy kit with very clear sujection and instuction. If your clutches do have some wear and take too long to apply even with the new parts it could still get the same simptons. This kit allows the trans to shift quicker by limiting the distance the apply and cushion pistons have to travel and change the resistance on them by differant springs. If followed right the trans will shift quicker but not much harder or if you go wild on it it will shift hard too. But this quicker shift will take up some of the time needed to shift the transmission and might spoof the computer into thinking your trans is shifting quick enough and not trip the 1811 pr 742 codes

[BNaylor]

Originally Posted by bens99gtp

the plugs you are questioning are for the neutral saftey switch. they tell the computer what gear you have selcted and also the small connector has the wire that comes from you ignition switch to the starter so un plug either one will cause your car not to start. i agree the most common problem in the TCC solenoid. But i would also spend the 50 bucks and replace the EPC as well. If the EPC ( which controls the pressure in the transmission) is not working low fluid pressure will casue slow soft shifts and the TCC to actualy slip more than the computer want it to which in turn can cause it max pressure out making shifting and application very hard. This extra pressure can then cause the releif part of the TCC solenoid to stick not allowing the fluid pressure to escape so when the car shifts into 2nd gear or higher the TCC is already on causing a very jerky shift and slugish acceleration and sometimes cause hardpart failure when going into 4th gear when it shift real hard. My sujetion from an ASE master tech is replace all the solenoids and switches in the side cover of the transmission. the EPC is like 50 buck and the shift solenoids are like 25 each and tcc is a touch more. There is also a FPS looks like a flat board all these go bad all the time spend the few extra bucks and replace them all at one time. givenm the fact the cradle has to come down to do all this why would you want to pay or do it twice seening it takes me about 3 hours to do it on a rack and i have done hundreds or these. I also recomend to my customer installing a light shift kit as sold on ZZPerformance. www.zzperformance.com its 30 bucks the reason i sujects this is not to make the trans shift harder but quicker this is super easy kit with very clear sujection and instuction. If your clutches do have some wear and take too long to apply even with the new parts it could still get the same simptons. This kit allows the trans to shift quicker by limiting the distance the apply and cushion pistons have to travel and change the resistance on them by differant springs. If followed right the trans will shift quicker but not much harder or if you go wild on it it will shift hard too. But this quicker shift will take up some of the time needed to shift the transmission and might spoof the computer into thinking your trans is shifting quick enough and not trip the 1811 pr 742 codes

Welcome to AF and thanks for contributing to the forum.

However, please consider checking the date of the thread and last post before posting and resurrecting old threads. This one goes back over 4 years. No problem raising old threads and throwing your two cents worth in but try do it without looking foolish.

[tblake]

What are you hinting at Bob?

I was just sort of wondering what an EPC is....

[BNaylor]

Originally Posted by tblake

What are you hinting at Bob?

I was just sort of wondering what an EPC is....

......

The EPC is the Pressure Control Solenoid.

[hammer2]

Hey, this was actually my thread! I still have the car and it still has the problem occasionally. I think I put some additives in it years ago. don't remember if they did any thing. Every once in a while it will start having problem shifting with sluggish acceleration like it is hunting for which gear to be in then the light comes on. the shifts are very hard and I take it easy-like let off gas when it shifts to avoid the jerking. after car sits and cools down, the next time i drive it everything will be fine except light stays on for maybe a day or so. years ago when I looked for hayes manual for the car, they didn't have them. they kept saying they would, but never did. so I wasn't willing to try to tackle it myself and I can't remember the last time I paid someone to work on one of my vehicles-too cheap I guess!

[BNaylor]

Originally Posted by hammer2

Hey, this was actually my thread!

Yeah thanks for the belated (over 4 years) feedback.

[bens99gtp]

just cause this was an old posting do u think ppl still are not having the same or similar problem with cars they have owned for awhile or maybe bought in the last 4 years. Cause i work on these at least once a week for the same issues. Excuse me for tossing a little into the pot to help ppl out. Cause if you do a search for this info on google it still pops up so that must mean ppl are still reading it. If my professional info isn;t wanted please say so and i will keep it to myself. But if ppl would like to have an idea what could be causing there issues the info is there. Its not like i have 3 years or schooling then GM training then 15 years of in feild experiance as a business owner and a grand prix owner since 99 to fall back on. Aand hammer2 you need to replace the TCC solenoid and EPC that and the mild shift kit i talked about from ZZpermance will take care of it. But if i were you i would replace the shift solenoid and pressure switch while there. The shift solenoid are held in with 1 clip[ each and switch has a few small bolts on it. Cheap to do once in there only cost parts. If your luck is like mine you will not do it then a few month later have to redo it for them and cost even more time and money. But i would like to know if ppl would like to hear my info on this or if i should had butted out since it was an old post

[BNaylor]

Originally Posted by bens99gtp

just cause this was an old posting do u think ppl still are not having the same or similar problem with cars they have owned for awhile or maybe bought in the last 4 years. Cause i work on these at least once a week for the same issues. Excuse me for tossing a little into the pot to help ppl out. Cause if you do a search for this info on google it still pops up so that must mean ppl are still reading it. If my professional info isn;t wanted please say so and i will keep it to myself. But if ppl would like to have an idea what could be causing there issues the info is there. Its not like i have 3 years or schooling then GM training then 15 years of in feild experiance as a business owner and a grand prix owner since 99 to fall back on. Aand hammer2 you need to replace the TCC solenoid and EPC that and the mild shift kit i talked about from ZZpermance will take care of it. But if i were you i would replace the shift solenoid and pressure switch while there. The shift solenoid are held in with 1 clip[ each and switch has a few small bolts on it. Cheap to do once in there only cost parts. If your luck is like mine you will not do it then a few month later have to redo it for them and cost even more time and money. But i would like to know if ppl would like to hear my info on this or if i should had butted out since it was an old post

Obviously you don't now how to read either. You were thanked for contributing to the forum so what more do you want other than going on a rant and repeating what you had posted or telling us what we already know.

Originally Posted by BNaylor

Welcome to AF and thanks for contributing to the forum.

Now you have given me a reason to close the thread. Thread closed!