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sprinkles08, ASE Certified Technician
Category: Car
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Experience:  ASE Master and Advanced level certified. Factory trained with 17 years dealership experience
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Volvo C70: I have a 2004 Volvo C70 Conv. the check engine light

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I have a 2004 Volvo C70 Conv. the check engine light and flashing arrow keep coming on, so I took it in and they replaced the valve body and the light still comes on with a different code this time 0740 . the first code was always 0700.
the car runs and shifts perfectly fine until this light comes on. When I take the code out it runs fine again. It usually happens at speeds over 50 MPH.

Hello and welcome to JustAnswer!


P0700 sets in the engine controller when there is a code stored in the trans controller. The one in the trans controller and pointing to the actual problem is the P0740.


This code sets when there is an issue on the torque converter clutch solenoid's control circuit. The converter clutch solenoid is on the valve body, I'm assuming that when the valve body was replaced it came with solenoids. If not, the converter clutch solenoid is the most likely cause for the code.


If the solenoid is new then it can be wiring between the trans and trans control module, or it could be the module itself. The next thing that would need to be done is test the wiring.

Customer: replied 4 years ago.

Hi, thanks for your reply, I was waiting to see if your advice was correct before the rating. I took the info to my mechanic. I should be able to rate by tomorrow I hope. Thanks for your patience

You're welcome!
Customer: replied 4 years ago.

It wasn't any of the things you mentioned in your answer??

I'm not confident in the diagnosis then. What did they tell you was wrong?
Customer: replied 4 years ago.

don't know yet that's where I was hoping you might help. They say they have to rebuild the transmission now.

What kind of shop is the car at? Dealer, trans shop, independent?

Have they told you what the actual failure is?

Customer: replied 4 years ago.

Berts Automotive Transmission Repair, Vancouver,B.C. Canada


I don't think they know. It seems to be a Sensor of some sort that keeps turning on the check engine light at any sustained speeds over 55 mph.

Before committing to any repair it wouldn't be a bad idea to get a second opinion. If they don't know what is wrong with it they shouldn't be selling you a major repair.

Customer: replied 4 years ago.

This was actually a third opinion. the original Volvo shop said I should replace the transmission. The other transmission shop said I should replace the valve body and so did these guys. So now I am stuck already for 3 grand and now it looks like another 3 grand, and that's with a break in labour supposedly. That's why I was reaching out to this forum to see if anyone has gone through this procedure before.

It sounds like everyone is guessing. Has noone tested the converter clutch solenoid's electrical circuit?

Was there debris in the pan when you remove it to replace the valve body?
Customer: replied 4 years ago.

no debris, he said that it looked like the transmission had been partially rebuilt before and he has to measure some rod and check a couple of other parts, but has to go into the transmission to do so. I am not sure if they tested the converter clutch solenoids electrical circuit. are these the solenoids that came with the new valve body? or something else

I would have expected the solenoid to come on the valve body if it was a new part.
Customer: replied 4 years ago.

they did, I wasn't sure if you might have been referring to some other solenoids. I am going to make sure that they test the converter clutch solenoids. are these the same solenoids as the ones on the body valve, because new ones did come with the body valve as well as wiring I believe

If the solenoid has been replaced then the solenoid's wiring in the engine/trans wiring harness needs to be tested. THis wouldn't be something that came with the valve body.
Customer: replied 4 years ago.

I will see if they have checked that possibility out. Thanks

You're welcome!
Customer: replied 4 years ago.

no one even mentioned the possiblility of it being the torque converter

The code is for the torque converter clutch's control solenoid circuit.
sprinkles08 and 3 other Car Specialists are ready to help you
Customer: replied 4 years ago.

Thanks for your answers, I have another shop going to change out the torque converter, as he checked all the electrical and it seems okay. He says the torqued converter is the only other possiblility. Hope he is right What do you think?

Customer: replied 4 years ago.
Relist: Incomplete answer.

There's no need to relist the question, simply hit the reply button if you need more help. I never got notification of your last reply because the question closed.


If all electrical components have been ruled out then it's possible that the converter could be the issue.