TCC Control Problem: ECM Gurus step inside please.
- Thread starter DaveP
- Start date
JSM
Active member
Re: TCC Control Problem: ECM Gurus step inside please.
I would agree a loose connection somewhere, or even bad ECM.
I wonder if you put an ohm meter on TCC signal to ground and watched it what would happen, you could ground the ecm side as a test and start to wiggle connections.
At one time there was schematics of the internals of the ECM on the net, I am sure they can be found if we look hard enough. I think guy's site that put them up was named Lucas.
Found the site: http://www.exatorq.com/ludis_obd1/1227749schematic.html
I would agree a loose connection somewhere, or even bad ECM.
I wonder if you put an ohm meter on TCC signal to ground and watched it what would happen, you could ground the ecm side as a test and start to wiggle connections.
At one time there was schematics of the internals of the ECM on the net, I am sure they can be found if we look hard enough. I think guy's site that put them up was named Lucas.
Found the site: http://www.exatorq.com/ludis_obd1/1227749schematic.html
DaveP
Active member
Re: TCC Control Problem: ECM Gurus step inside please.
Brake switch is OK. First thing I tried when it first did it a couple of days ago.
With my light across the ALDL, a loss of power from the brake switch would be a loss of power to the light. So the TCC solenoid would go off, but the light would stay off too. Because there's no power to it. Because the light is flickering, it's a control-side issue. Not power side.
Thanks for the thoughts.
Brake switch is OK. First thing I tried when it first did it a couple of days ago.
With my light across the ALDL, a loss of power from the brake switch would be a loss of power to the light. So the TCC solenoid would go off, but the light would stay off too. Because there's no power to it. Because the light is flickering, it's a control-side issue. Not power side.
Thanks for the thoughts.
Gnocide
turbo game burt reynolds
Re: TCC Control Problem: ECM Gurus step inside please.
Dave, does this sound like your issue below?
if the switch is going bad
it will lock and unlock randomly- using cruise control At 45MPH will make it kick in and out.
my grand national did this for about a month.
if this sounds like it, IF...
you just need the switch for about $15 FROM BULKPART.COM http://www.bulkpart.com/2/product/4L60-700R4solenoid/54425B.html
if not, disregard everything i just posted.
Dave, does this sound like your issue below?
if the switch is going bad
it will lock and unlock randomly- using cruise control At 45MPH will make it kick in and out.
my grand national did this for about a month.
if this sounds like it, IF...
you just need the switch for about $15 FROM BULKPART.COM http://www.bulkpart.com/2/product/4L60-700R4solenoid/54425B.html
if not, disregard everything i just posted.
Last edited:
warmpancakes
New member
Re: TCC Control Problem: ECM Gurus step inside please.
I had same issue with my truck I had too low of a T-stat in truck changed to 180 problem solved
I had same issue with my truck I had too low of a T-stat in truck changed to 180 problem solved
DaveP
Active member
Re: TCC Control Problem: ECM Gurus step inside please.
Right now, I don't think it's the brake switch. I want to drive it with a jumper in the ALDL terminals, which will lock the TCC =ON. If the ECM control is responsible for the jumping in and out, then this will override the ECM. If it does it with it locked ON, then it could be the brake switch.
Thanks for the input.
Right now, I don't think it's the brake switch. I want to drive it with a jumper in the ALDL terminals, which will lock the TCC =ON. If the ECM control is responsible for the jumping in and out, then this will override the ECM. If it does it with it locked ON, then it could be the brake switch.
Thanks for the input.
DaveP
Active member
Re: TCC Control Problem: ECM Gurus step inside please.
I had it on an Auto-X-Ray scanner this afternoon. CTS was 182º. It's a stock PROM, so 182º should be fine.
Thanks for the input.
That's a really good reminder, Ken. I forgot about CTS influence.
I had it on an Auto-X-Ray scanner this afternoon. CTS was 182º. It's a stock PROM, so 182º should be fine.
Thanks for the input.
Gnocide
turbo game burt reynolds
Re: TCC Control Problem: ECM Gurus step inside please.
IM TALKING ABOUT THE SOLENOID IN THE TRANS NOT THE BRAKE SWITCH.
SORRY for confusion
see picture above
IM TALKING ABOUT THE SOLENOID IN THE TRANS NOT THE BRAKE SWITCH.
SORRY for confusion
see picture above
warmpancakes
New member
Re: TCC Control Problem: ECM Gurus step inside please.
I had the issue with a 160 stat, and cannot remember what coolant temp must be for lockup to occur
I had the issue with a 160 stat, and cannot remember what coolant temp must be for lockup to occur
Gnocide
turbo game burt reynolds
Re: TCC Control Problem: ECM Gurus step inside please.
i run a 160 t stat for 13 years and never had a lock up problem.
lock up occurs at 42-44mph stock- the trans will kick it in and out if the tcc switch is bad.
i run a 160 t stat for 13 years and never had a lock up problem.
lock up occurs at 42-44mph stock- the trans will kick it in and out if the tcc switch is bad.
dgoodhue
BuSTeD 4.3
Re: TCC Control Problem: ECM Gurus step inside please.
I looked at the factory schematic for the TCC lockup. It looks like you have it wired to circuit 422. I agree that if it was an issue in the solenoid, trans temperature switch or Brake switch it would flicker all the time, not only when the TCC locked. (BTW I didn't realized their was a 1 Ohm resistor or blocking Diode in the 420 circuit until today either, I imagine those are in the wire harness somewhere.)
I looked through the 749 schematic, Usually there should be analog and digital grounds, the different grounds aren't differentiate on that schematic. The F4 pin uses a digital ground (it basically goes through a NAND gate, a digital circuit). Looking at the two grounds, It should be 551 (G108) since the 450 goes to the O2 Sensor which an analog input. I think that is the cylinder head ground.
I looked at the factory schematic for the TCC lockup. It looks like you have it wired to circuit 422. I agree that if it was an issue in the solenoid, trans temperature switch or Brake switch it would flicker all the time, not only when the TCC locked. (BTW I didn't realized their was a 1 Ohm resistor or blocking Diode in the 420 circuit until today either, I imagine those are in the wire harness somewhere.)
I looked through the 749 schematic, Usually there should be analog and digital grounds, the different grounds aren't differentiate on that schematic. The F4 pin uses a digital ground (it basically goes through a NAND gate, a digital circuit). Looking at the two grounds, It should be 551 (G108) since the 450 goes to the O2 Sensor which an analog input. I think that is the cylinder head ground.
DaveP
Active member
Re: TCC Control Problem: ECM Gurus step inside please.
Thanks, Dave.
Good thoughts on the digital vs analog grounds. That kind of thinking is above my pay-grade. I'm going to look at the ECM connections later this morning. Thanks for the feedback.
Cir 551 G108 (tan/blk) is at front-center of engine.
Cir 413 G107 (tan) (O2 sensor ground) is LR of engine (cyl head).
I've found the blocking diode in 422 purple TCC power wire when working on engine harnesses. It is located in the main trunk, about under the wiper motor. Wrapped in tape, and looks like a splice, but only one wire in, one wire out.
Thanks, Dave.
Good thoughts on the digital vs analog grounds. That kind of thinking is above my pay-grade. I'm going to look at the ECM connections later this morning. Thanks for the feedback.
Cir 551 G108 (tan/blk) is at front-center of engine.
Cir 413 G107 (tan) (O2 sensor ground) is LR of engine (cyl head).
I've found the blocking diode in 422 purple TCC power wire when working on engine harnesses. It is located in the main trunk, about under the wiper motor. Wrapped in tape, and looks like a splice, but only one wire in, one wire out.
dgoodhue
BuSTeD 4.3
Re: TCC Control Problem: ECM Gurus step inside please.
I looked through tunerpro for TCC lockup contreol. The ECM TCC does have minimum temperature to enable TC lockup, its about 140 degrees. There are few scalar for decelaration for unlocking they are all based on Speed or TPS%. I found a load vs speed for 3rd gear lock up.
The only two sensors I could see affecting the ECM commanding the TCC is an intermittent TPS or Coolant Temperature.
I looked through tunerpro for TCC lockup contreol. The ECM TCC does have minimum temperature to enable TC lockup, its about 140 degrees. There are few scalar for decelaration for unlocking they are all based on Speed or TPS%. I found a load vs speed for 3rd gear lock up.
The only two sensors I could see affecting the ECM commanding the TCC is an intermittent TPS or Coolant Temperature.
DaveP
Active member
Re: TCC Control Problem: ECM Gurus step inside please.
I've blown 3 more fuses testing this thing. I'm now leaning towards it being a bad TCC Solenoid. Genocide gets the SyTy bucks. I think what's happening is the solenoid is semi-shorted internally. The resistance gets low enough that the ECM can't sink the increased amperage to ground, and the solenoid drops out. If I over-ride the ECM with the jumper to ground, the increased current blows the fuse.
I'm taking it to Reno for Thanksgiving to spend the holiday with my transmission builder buddy and his family. I'll leave it at his shop, and he and I can go down on Friday and change the solenoid out after its cooled off. I don't feel like messing with it before I leave on Wednesday morning.
Thanks for the help and interest.
I've blown 3 more fuses testing this thing. I'm now leaning towards it being a bad TCC Solenoid. Genocide gets the SyTy bucks. I think what's happening is the solenoid is semi-shorted internally. The resistance gets low enough that the ECM can't sink the increased amperage to ground, and the solenoid drops out. If I over-ride the ECM with the jumper to ground, the increased current blows the fuse.
I'm taking it to Reno for Thanksgiving to spend the holiday with my transmission builder buddy and his family. I'll leave it at his shop, and he and I can go down on Friday and change the solenoid out after its cooled off. I don't feel like messing with it before I leave on Wednesday morning.
Thanks for the help and interest.
skwayb
NWSTP
Re: TCC Control Problem: ECM Gurus step inside please.
The F4 Pin controls the TCC.
http://www.nwstp.com/chips/P4_docs/749sunbird3.jpg
Pinouts.. Check the ones labeled Ground...
http://www.nwstp.com/chips/P4_docs/749sunbird6.jpg
http://www.nwstp.com/chips/P4_docs/749sunbird6.jpg
The Brake Switch and Solenoid are the only things that could cause it besides the ECM.
F4 is an output on the quad driver.
http://www.exatorq.com/ludis_obd1/1227749sheet5.gif
Upper left corner you will see quad out.
I would try the brake switch.. It caused mine to have a problem before.
The F4 Pin controls the TCC.
http://www.nwstp.com/chips/P4_docs/749sunbird3.jpg
Pinouts.. Check the ones labeled Ground...
http://www.nwstp.com/chips/P4_docs/749sunbird6.jpg
http://www.nwstp.com/chips/P4_docs/749sunbird6.jpg
The Brake Switch and Solenoid are the only things that could cause it besides the ECM.
F4 is an output on the quad driver.
http://www.exatorq.com/ludis_obd1/1227749sheet5.gif
Upper left corner you will see quad out.
I would try the brake switch.. It caused mine to have a problem before.
Gnocide
turbo game burt reynolds
Re: TCC Control Problem: ECM Gurus step inside please.
i finally get to help you for a change?
makes me feel good about all the stuff Ive read and used from you in a ton of your posts.
you know like cladding paint number-WA 8798 for a certain typhoon redo!
i finally get to help you for a change?
makes me feel good about all the stuff Ive read and used from you in a ton of your posts.
you know like cladding paint number-WA 8798 for a certain typhoon redo!
TYRODD
My ass. Look at it.
Re: TCC Control Problem: ECM Gurus step inside please.
I saw this post while in GA...needed some input on my problem.
My truck has the ON/OFF/ON/OFF TCC issue also, but it is only when under load.
On the highway cruising, the TCC engages and acts normal. However when I punch the gas to pass, the clutch will unlock and lock in a very "controlled" manner, it is not random.
Built trans and a BH/2800 9/11. Imagine how wild it gets on a drag strip when my RPMs are jumping 300rpm back and forth, truck tries to bounce of the rev limiter if I keep my foot down. Of course I can keep my left foot down just enough to press the brake switch and keep the clutch disengaged, but what's the point of that?
I've also replace the solenoid-no change.
I saw this post while in GA...needed some input on my problem.
My truck has the ON/OFF/ON/OFF TCC issue also, but it is only when under load.
On the highway cruising, the TCC engages and acts normal. However when I punch the gas to pass, the clutch will unlock and lock in a very "controlled" manner, it is not random.
Built trans and a BH/2800 9/11. Imagine how wild it gets on a drag strip when my RPMs are jumping 300rpm back and forth, truck tries to bounce of the rev limiter if I keep my foot down. Of course I can keep my left foot down just enough to press the brake switch and keep the clutch disengaged, but what's the point of that?
I've also replace the solenoid-no change.