Torque convertor clutch circuit code came up

**Speedy_Gonzales** · 02-05-2008, 02:07 PM

My car is still sticking in 3rd and the local chevy dealer scanned it and it brought up this code: P0740................So I look it up and the code means , Torque convertor clutch circuit. What should the cost be to fix this and is it something I could do myself ?

**cabel** · 02-05-2008, 04:52 PM

Subject: MIL On, Transmission Stuck in Second or Third Gear, IPC Inoperative, DTCs P0740,P0753,P0758,P0785,P0787,P0973,P0976,P1860,P2 761,P2764 and/or P2769 Set (Verify and Repair Source of Voltage Loss #01-07-30-002E - (09/23/2005)

Models: 2006 and Prior GM Passenger Cars and Light Duty Trucks
2005-2006 HUMMER H2
2006 HUMMER H3
2005-2006 Saab 9-7X
with 4L60-E, 4L65-E, 4L80-E or 4L85-E Automatic Transmission (RPOs M30, M32, M33, MT1, MN8)

This bulletin is being revised to update model years, add additional models and add additional diagnostic information. Please discard Corporate Bulletin Number 01-07-30-002D (Section 07 -- Transmission/Transaxle).
Condition

Some customers may comment on one or more of the following conditions:
• The Malfunction Indicator Lamp (MIL) is ON.
• The transmission is defaulted to second gear (4L80/85-E).
• The transmission is defaulted to third gear (4L60/65-E).
• The instrument cluster is inoperative.

Upon investigation, one or all of the diagnostic trouble codes (DTCs) P0740, P0753, P0758, P0785, P0787, P0973, P0976, P1860, P2761, P2764 and P2769 may be set depending on the vehicle.
Cause

The most likely cause of this condition may be a loss of voltage to the transmission solenoid power supply circuit.

This condition may also be the result of an incorrect installation of an aftermarket electronic device such as a remote starter or alarm system.
Correction

Important: If the vehicle is equipped with an aftermarket electronic device and the DTCs are being set when the device is being used, verify that the appropriate fuse is being supplied battery voltage during operation. If voltage is not present at this fuse, these DTCs will be set due to lack of voltage at the solenoids. This condition is most likely to occur with an incorrectly installed remote starting system. If this is the case, refer the customer to the installer of the system for corrections. ANY REPAIRS DUE TO AFTERMARKET INSTALLATION OF ACCESSORIES IS A NON-WARRANTABLE ITEM.

1. With the ignition switch in the RUN position, test for battery voltage at the circuit fuse in the transmission solenoid power supply circuit. Refer to the appropriate SI Document for the transmission solenoid power supply circuit information.
2. If battery voltage is present at the fuse, inspect the ignition voltage circuit between the fuse and the transmission for possible opens.
3. If battery voltage is not present at the fuse, test for continuity between the fuse and the ignition switch. If NO continuity is between the fuse and the ignition switch, repair the open in that circuit.
4. If you have continuity between the fuse and the ignition switch, the most likely cause is the ignition switch. Replace the ignition switch using the appropriate Ignition Switch Replacement procedure in SI. Refer to group number 2.188 of the parts catalog for part description and usage of the ignition switch.

hope this helps. Sounds like a loss of battery power to the trans

**Speedy_Gonzales** · 02-05-2008, 05:04 PM

Originally Posted by cabel

Subject: MIL On, Transmission Stuck in Second or Third Gear, IPC Inoperative, DTCs P0740,P0753,P0758,P0785,P0787,P0973,P0976,P1860,P2 761,P2764 and/or P2769 Set (Verify and Repair Source of Voltage Loss #01-07-30-002E - (09/23/2005)

Models: 2006 and Prior GM Passenger Cars and Light Duty Trucks
2005-2006 HUMMER H2
2006 HUMMER H3
2005-2006 Saab 9-7X
with 4L60-E, 4L65-E, 4L80-E or 4L85-E Automatic Transmission (RPOs M30, M32, M33, MT1, MN8)

This bulletin is being revised to update model years, add additional models and add additional diagnostic information. Please discard Corporate Bulletin Number 01-07-30-002D (Section 07 -- Transmission/Transaxle).
Condition

Some customers may comment on one or more of the following conditions:
• The Malfunction Indicator Lamp (MIL) is ON.
• The transmission is defaulted to second gear (4L80/85-E).
• The transmission is defaulted to third gear (4L60/65-E).
• The instrument cluster is inoperative.

Upon investigation, one or all of the diagnostic trouble codes (DTCs) P0740, P0753, P0758, P0785, P0787, P0973, P0976, P1860, P2761, P2764 and P2769 may be set depending on the vehicle.
Cause

The most likely cause of this condition may be a loss of voltage to the transmission solenoid power supply circuit.

This condition may also be the result of an incorrect installation of an aftermarket electronic device such as a remote starter or alarm system.
Correction

Important: If the vehicle is equipped with an aftermarket electronic device and the DTCs are being set when the device is being used, verify that the appropriate fuse is being supplied battery voltage during operation. If voltage is not present at this fuse, these DTCs will be set due to lack of voltage at the solenoids. This condition is most likely to occur with an incorrectly installed remote starting system. If this is the case, refer the customer to the installer of the system for corrections. ANY REPAIRS DUE TO AFTERMARKET INSTALLATION OF ACCESSORIES IS A NON-WARRANTABLE ITEM.

1. With the ignition switch in the RUN position, test for battery voltage at the circuit fuse in the transmission solenoid power supply circuit. Refer to the appropriate SI Document for the transmission solenoid power supply circuit information.
2. If battery voltage is present at the fuse, inspect the ignition voltage circuit between the fuse and the transmission for possible opens.
3. If battery voltage is not present at the fuse, test for continuity between the fuse and the ignition switch. If NO continuity is between the fuse and the ignition switch, repair the open in that circuit.
4. If you have continuity between the fuse and the ignition switch, the most likely cause is the ignition switch. Replace the ignition switch using the appropriate Ignition Switch Replacement procedure in SI. Refer to group number 2.188 of the parts catalog for part description and usage of the ignition switch.

hope this helps. Sounds like a loss of battery power to the trans

yes it helps alot. I been doing some research and had found out it was the solenoid or the trans plug. The dealer did say it might be the ignition switch and I was a little worried that might be trying to screw me. But they read just what your posted. Where did u get that at ? Thanks for the post

**Speedy_Gonzales** · 02-06-2008, 12:25 PM

the chevy dealer said it needs a solenoid switch and the ignition switch. Parts/labor $375

**xtremetrans** · 02-06-2008, 07:25 PM

Most likely it is your wiring harness inside your trans.It includes the lock-up solenoid. The wires usually become brittle and short to ground. Usually when you have an ignition switch problem you get more than one code because the voltage coming from the ignition switch powers all the shift and lock up solenoids in the trans. I would have them do a resistance check on the lock up solenoid first.

**Speedy_Gonzales** · 02-06-2008, 07:33 PM

Originally Posted by xtremetrans

Most likely it is your wiring harness inside your trans.It includes the lock-up solenoid. The wires usually become brittle and short to ground. Usually when you have an ignition switch problem you get more than one code because the voltage coming from the ignition switch powers all the shift and lock up solenoids in the trans. I would have them do a resistance check on the lock up solenoid first.

thats what another dealer said when I called..........if it were the ignition switch it would be more than 1 code........they supposely checked both and they show bad.......now for some reason its taking longer than expected

**xtremetrans** · 02-06-2008, 08:41 PM

It does not make sense that both are bad. How did they conclude that the ignition switch was bad? They probably want to change both to cover their ass or to make more money on the ticket, but I rarely see both go bad at the same time.

**Speedy_Gonzales** · 02-07-2008, 03:03 AM

Originally Posted by xtremetrans

It does not make sense that both are bad. How did they conclude that the ignition switch was bad? They probably want to change both to cover their ass or to make more money on the ticket, but I rarely see both go bad at the same time.

they expalined why but I forget what he said exactly . I talked with the Service manager about all of it. This IGNTION SWITCH is $190 more.Getting screwed I guess.I will just be happy to get the car back and never go back there

**Speedy_Gonzales** · 02-07-2008, 02:51 PM

I got the car back today. $342 labor/parts............their explanation: Internal 3-2 solenoid damaged due to ignition switch voltage, replaced 3-2 solenoid and ignition switch

**Speedy_Gonzales** · 02-08-2008, 10:21 AM

Originally Posted by xtremetrans

It does not make sense that both are bad. How did they conclude that the ignition switch was bad? They probably want to change both to cover their ass or to make more money on the ticket, but I rarely see both go bad at the same time.

BAD NEWS.................headed to work this morning and car started doing the same thing. took it back to the chevy place. they said they would check it out and see whats going on. next thing I know the service manager comes out thinks he is going to bully me around and push me out the door. Long story short after going round and round with him and talking with the main manager they put my old parts back in and gave me my money back. The service manager and I did take it for a ride but of course it didnt act up while he drove it. Took it to another place but its Monday before they can look at it.

Question: They said they replaced solenoid 3:2. Is that the right one to replace if its in limp mode and stuck in 3rd ??????

Also I saw the pan and it did have some metal shavings in the bottom of the it. What does that indicate ?

**xtremetrans** · 02-08-2008, 08:57 PM

I dont know why they changed your 3-2 downshift sol. when you got a P0740. That has nothing to do with that code. If I were you I would take it to a good tranny shop so they can diagnose the problem once and for all.

**Speedy_Gonzales** · 02-08-2008, 09:08 PM

Originally Posted by xtremetrans

I dont know why they changed your 3-2 downshift sol. when you got a P0740. That has nothing to do with that code. If I were you I would take it to a good tranny shop so they can diagnose the problem once and for all.

Its at another shop right now, they are suppose to look at it Monday. With that code which one should have been replaced ?

**xtremetrans** · 02-08-2008, 10:02 PM

For a code P0740 you would change the TCC (lock-up) sol., but the internal wiring harness is attached to it, so you would have to change it too. Usually it is the harness that causes the problem because the wires become brittle and the wire is exposed and it shorts with another wire or shorts to ground on the valve body.

**Speedy_Gonzales** · 02-08-2008, 10:40 PM

Originally Posted by xtremetrans

For a code P0740 you would change the TCC (lock-up) sol., but the internal wiring harness is attached to it, so you would have to change it too. Usually it is the harness that causes the problem because the wires become brittle and the wire is exposed and it shorts with another wire or shorts to ground on the valve body.

the TCC is what another guy told me. The harness is it called a TRANS PLUG also ? The dealership tried their best to screw me over............sad part is they had lots of cars lined up for service

thanks for your replys

**Speedy_Gonzales** · 02-12-2008, 03:38 PM

the place my car is at now scanned it and this code came up: PO785

**xtremetrans** · 02-13-2008, 09:00 AM

The P0785 is for the 3-2 downshift sol.. Does it also have the P0740 or just the P0785?

**Speedy_Gonzales** · 02-13-2008, 03:57 PM

Originally Posted by xtremetrans

The P0785 is for the 3-2 downshift sol.. Does it also have the P0740 or just the P0785?

now it only has the PO785 in it.........the first shop I took it to replaced that solenoid for some reason even though they said P0740 came up. But the car still wouldnt shift into 4th

**Speedy_Gonzales** · 02-13-2008, 03:58 PM

Originally Posted by xtremetrans

For a code P0740 you would change the TCC (lock-up) sol., but the internal wiring harness is attached to it, so you would have to change it too. Usually it is the harness that causes the problem because the wires become brittle and the wire is exposed and it shorts with another wire or shorts to ground on the valve body.

the second place I took my car to tried to rip me off also. He wanted to charge me $400 and said all the solenoids needed replaced and the wire harness. I told him I would just pick my car up not to do anything else. When I asked him how the filter and bottom of the pan looked he said they didnt drop the pan only did pressure test on the solenoids. I paid him $55 to find out the problem but all he really did was scan for a code. Thats ok he didnt get anymore $$$ from me. On the way home since the service engine soon light was on I stopped by Auto Zone and had them scan it. I wanted to see if he was tellling the truth about what code came up. They scanned it and P0785 came up. The same one he said came up. I asked him if a bad wire harness could make codes go off for different solenoids and he said yes. Then he went on to say that I didnt need to just replace 1 solenoid that I needed to replace all of them, that it wasnt good to just do one. I think he was just wanting more money, wanting to put parts on I didnt need.

I went by a Chevy dealer and bought the TCC Solenoid w/ the wire harness. I am going to try that and see if it takes care of the problem. Performabuilt/Xtremetrans could you tell me again the steps to do in replacing the TCC and wire harness ? Will I need to clear out the code after the TCC install ? Any pics/diagrams would be very helpful. I have been searching online for write-ups on this subject but have had no luck.

__________________

**tctech1** · 02-17-2008, 07:57 AM

trans probs are the worst because obd2 was made for engine diagnostics such as drivability or emissions. the code gives little to go on. it could be a little thing like a sol. or wiring problem or it could be internal, clutch packs ect. i have heard bad things on the original wiring for that particular trans though and sol. do go bad but if you have metal in the pan its def. not a good sign and should start saving on a rebuild or even a new one. new is better, i never had any codes pop up before i had my trans rebuilt and now the light comes on once a week for a p0740. of course the shop says they cant find anything wrong with it and yet they wont try anything except hook up the scanner. good luck on finding a good transmission person they normally dont have diagnostic skills they just say " it needs to be rebuilt and we wont know how much its gonna cost until we get into it".lol

**Speedy_Gonzales** · 02-17-2008, 08:15 AM

Originally Posted by tctech1

trans probs are the worst because obd2 was made for engine diagnostics such as drivability or emissions. the code gives little to go on. it could be a little thing like a sol. or wiring problem or it could be internal, clutch packs ect. i have heard bad things on the original wiring for that particular trans though and sol. do go bad but if you have metal in the pan its def. not a good sign and should start saving on a rebuild or even a new one. new is better, i never had any codes pop up before i had my trans rebuilt and now the light comes on once a week for a p0740. of course the shop says they cant find anything wrong with it and yet they wont try anything except hook up the scanner. good luck on finding a good transmission person they normally dont have diagnostic skills they just say " it needs to be rebuilt and we wont know how much its gonna cost until we get into it".lol

I am in the process of replacing the wire harness, TCC solenoid, 3-2 solenoid and the filter. Sometimes the car wont shift into 4 sometimes it works normal. If what I have done doesnt fix it I did find a good tranny shop that is honest and does great work