Check Engine Light -- P0740 Torque Converter Clutch Solenoid Circuit, on 2002 Chrysler

Hi all

I drive a 2002 Chrysler Sebring convertible with about 130,000 miles on it.

I was driving down the highway in early November when the check engine light came on my car. I took it to Aamco who did some diagnosis and replaced a solenoid assembly in the transmission. The light went off and I was on my way. I never got the exact code.

About a month after that, the light came on again. This time, I got a low end code reader and scanned it myself. I got a “P0700” code, which I’ve read is a generic code that the transmission system sends to the computer or something. So I used my reader to erase it. However, the light came on 2 days later while I was driving down the highway at about 70 MPH.

So I went to an auto parts store to get a more detailed scan with a better tool. This one came up “P0740 Torque Converter Clutch Solenoid Circuit”.

This feels weird, because the solenoid assembly was just replaced a month ago (and is still under warranty).

The car seems to drive okay. I don’t notice any actual problems in shifting. The tachometer seemed to get up to about 3000 RPM on the highway. But I’ve seen practically new cars do that. The last time I had serious transmission problem it would rev up to about 5000 or 6000 RPM on the highway and still only getting up to about 40 MPH. That was 3 years ago and at the time I had a fairly expensive transmission repair (which included a new torque converter).

But like I said, the car seems to be driving okay. I don’t drive much. Maybe 100 miles a week? And even that is mostly optional in town driving. I’m not looking to keep this car for more than another 20,000 to 25,000 miles though for the time being I cannot afford a new one.

What are the possible causes here? What are the consequences of ignoring this? Like I said, it’s still driving fine and as the old saying goes “if it’s not broke, don’t fix it”.

Probably torque converter clutch isn’t working (ie isn’t locking up at highway speed. Normally it should lock up at 45+ mph).The result is slightly higher engine RPM on the highway and worse gas mileage. You don’t absolutely need to fix it, but your highway mpg will suffer. And it won’t make any difference at all below 45 mph or so, since the TCC doesn’t lock up below that anyway.

Hmm. If worst case scenario is that my gas mileage is going to get even worse on the rare occasion that I do take it out on the highway, I think I can live with it. Right now I’m in college and starting my last semester in January, hoping to get back to the workforce after that and am strongly considering getting a new car within a year. I only put about 7500 miles a year on this thing. is a good site that specializes in Chrysler Corp. vehicles. I have found it helpful with questions about my minivans. You might inquire there.

If the code indicates a problem in the circuit, that could mean wires and connectors, etc., not the solenoid assembly itself. Maybe Aamco missed something in their diagnosis.

Given your limited driving and plan to sell it within the year, I wouldn’t spend money to fix it. But if you could get it fixed under warranty (you said the solenoid was replaced a month ago) it might help resale value when you sell it.

You may have a hard time selling it with the light on if you are in an area that requires a smog inspection before the sale. A check engine light will be a failure.

You state that a solenoid was replaced by AAMCO last month. Was the solenoid that was replaced the one in question now?

If not, you could consider adding a can of Berryman B-12 to the transmission fluid on the offchance that a solenoid, plunger, or check ball is sticking the valve body.
The B-12 could possibly clear up something like this. It’s also cheap and easy.

I wasn’t really planning to resell it actually. My plan is, once I have the money to get a replacement car, to drive this one until something catastrophic happens and sell it to a salvage yard, or just donate it to NPR or something.