P0740
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From: St.Peters, MO/ Carbondale, Il
P0740 Just put in a performabilt lvl2 that i bought off a member on here. I drove the car for a bit no codes or anything. Now it doesn't have overdrive. Went to get it tuned and my tuner couldn't force the tcc solenoid to work. I test the tan/black wire on the main harness going into the trans with the tranny in the OD position and key on ignition off and only found 2 volts. Anyone have any ideas?
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From: St.Peters, MO/ Carbondale, Il
From performabilt's website
We also eliminate the partial lockup function GM mistakenly engineered into the 4L60E transmission, thus eliminating converter shudder, premature converter clutch failure, and the well known code 1870, which causes high "line pressure", no fourth gear, and teeth cracking shifts at low throttle. Lockup is either OFF or ON, not slipping off and on as it did with the factory PWM working. This does not affect performance, but it does have the added advantage of increasing low speed fuel efficiency, which at today's fuel prices is like getting a bonus. In addition this mod along with others alow us to use later valvebodies on older units to improve performance and increase interchangability and reliability.
So how is this done and could it cause this solenoid to not work. Where does the solenoid ground to also? Is it a common ground?
We also eliminate the partial lockup function GM mistakenly engineered into the 4L60E transmission, thus eliminating converter shudder, premature converter clutch failure, and the well known code 1870, which causes high "line pressure", no fourth gear, and teeth cracking shifts at low throttle. Lockup is either OFF or ON, not slipping off and on as it did with the factory PWM working. This does not affect performance, but it does have the added advantage of increasing low speed fuel efficiency, which at today's fuel prices is like getting a bonus. In addition this mod along with others alow us to use later valvebodies on older units to improve performance and increase interchangability and reliability.
So how is this done and could it cause this solenoid to not work. Where does the solenoid ground to also? Is it a common ground?
Just put in a performabilt lvl2 that i bought off a member on here. I drove the car for a bit no codes or anything. Now it doesn't have overdrive. Went to get it tuned and my tuner couldn't force the tcc solenoid to work. I test the tan/black wire on the main harness going into the trans with the tranny in the OD position and key on ignition off and only found 2 volts. Anyone have any ideas?
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From: St.Peters, MO/ Carbondale, Il
i checked it at the trans connector. It had only 2 volts. My last trans kept destroying the 3-4 clutch pack. Lock up worked fine. Put the new trans in now i have no lock up. We couldnt force it to lock up with hp tuners or a tech two
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Ok the car is put away for winter and I'm attempting some diagnostic stuff on it. The PWM solenoid works as well as the tcc solenoid if tested at the solenoids. Now could the wiring leading to either of them be causing this issue? I have the harness out of my original trans that was known to work, but I'm having trouble getting the main connector out? How do I accomplish that? Is it possible without lowering the trans or anything?
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Well First with the key on and engine off the PCM would not have the solenoid grounded so you should see Battery voltage
the PCM grounds the tan/blk wire to engage lockup.
You can do a simple test with the car running in gear and brake applied ground the tan/blk wire this should lock the converter and either stall the car or bog down if bogs dont keep it that way.
If this does not happen, Then either you have a lockup solenoid issue or possibly the oring on the shaft was danaged during installation.
the PCM grounds the tan/blk wire to engage lockup.
You can do a simple test with the car running in gear and brake applied ground the tan/blk wire this should lock the converter and either stall the car or bog down if bogs dont keep it that way.
If this does not happen, Then either you have a lockup solenoid issue or possibly the oring on the shaft was danaged during installation.
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From: St.Peters, MO/ Carbondale, Il
Could this also be wiring related? I tested at the tan and black wire and only got 2 volts after I wiggled the wire. Before that it got 0. Could the harness in the trans have a high resistance or the solenoid itself be shorted?
Edit: I'm looking at the diagram right now. With the KOEO (off), shouldnt the solenoid be open? Meaning you would see 0 volts on the tan/black wire coming from the trans. If I'm reading what you're saying correctly I should see 12 volts at that tan/black wire with the KOEO. Sorry for all the double checking and stuff. I took my electrical diagnosing class like a year ago and havent had much practice at it since then.
Edit: I'm looking at the diagram right now. With the KOEO (off), shouldnt the solenoid be open? Meaning you would see 0 volts on the tan/black wire coming from the trans. If I'm reading what you're saying correctly I should see 12 volts at that tan/black wire with the KOEO. Sorry for all the double checking and stuff. I took my electrical diagnosing class like a year ago and havent had much practice at it since then.
Last edited by zed28camaro; Jan 12, 2011 at 08:00 PM.
The 12 volts to the solenoid is constant with the key on, and with no ground to the tan/black side you should see 12v batt volts if the circuits complete through the trans.
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From: St.Peters, MO/ Carbondale, Il
Just for people that might use this thread for future reference. I put a harness without those dumb bullet connectors for the solenoid in and now I have lock up all the time. I appreciate the feedback I did get in here just to confirm I wasn't swapping parts for no reason. I especially appreciate the help from Performabuilt seeing as they built the trans and giving great information as to what tests to perform.
