Recurring check engine light issue on 2007 Toyota Matrix

I bought a 2007 Toyota Matrix new, and it now has 41,800-something miles on it. At 38K miles the check engine light came on while I was on vacation out of state. The nearest Toyota dealer checked it out, told me the check engine light code was P0741 - problem with the torque converter - but they didn’t see any obvious problem and the car drove fine for them and for me. They turned the light off but it went back on before very long. The car has now been to 2 different Toyota dealerships near my home because the check enginel light keeps turning on. They also report seeing the same code, also seeing nothing obviously amiss,and tell me I need my transmission replaced for $4000. This seems preposterous to me for such a low mileage Toyota.

In December, when the check engine light went on again, I discovered it would turn off if I filled the car with gas. It still comes back on; if I either fill the car with gas, or simply open and close the gas cap, the check engine light will turn off after 3 - 4 trips with the car.

I’m baffled. What does the gas cap have to do with the torque converter?

What’s really weird is that the light always comes on under the same conditions. Most of my driving is short trips, a couple of miles in town at around 30 mph. The light never comes on during “town” driving. My highway driving consists of trips of about 1 hour; parking for an hour or two; then returning home – again, about an hour’s drive. The check engine light always comes on when I’m doing highway driving on the trip home. I’ve clocked the mileage for the last 3 times the light came on. It came on after highway driving a total of 48, 51, and 48 miles, respectively.

I’d appreciate thoughts on what the problem could be, and what the solution might be, too. Do I really need a new transmission? As you probably suspect, I’m not terribly knowledgeable about cars; and the folks at Toyota probably suspect that, too…


Cat Fur (New York)

It is saying that your torque converter is not locking up properly. This could simply be a faulty TCC solenoid and should not cost much to repair. But I’d first look at the transmission fluid. Toyota claims this is a no maintenance item, but they are wrong. If the fluid is not red and clear, then it needs to be changed.

If you have ever had the transmission flushed, especially by a quick lube place, then you must immediately take it to the dealer and have them drain and remove the pan, clean the filter and replace the pan and refill. Then, if they have a fluid replacement machine, they can hook it up and finish flushing out the wrong fluid that is still in there. But the pan has to be dropped first or they will never get all the old stuff out, despite their claims that it does.

If they don’t have a fluid exchange machine, then go back a week or two later and have the ATF drained and refilled again, they won’t need to drop the pan the second time. But only Toyota T-IV fluid must be used, the universal stuff the quicky lube places use will cause problems like yours.

I suspect the CEL that is coming on after filling the tank (do not overfill as this can cause a CEL) or removing the cap is due to a different code. You will need to get that one read.

DTC P0741 TCC System Stuck Off

+1 to Keith’s excellent post.
Including the comment about there being a different code. The gas cap has absolutely nothing to do with the torque converter.

Thanks, folks. The CEL goes OFF after I fill the tank or re-do the gas cap. The last time I took it to Toyota they checked the trasmission fluid & said it was fine. I’m glad to hear my “suspicion” that the gas cap & torque converter don’t relate to each other. I wonder why they don’t want to fix the solenoid and insist on replacing the whole transmission?

Cat Fur

Find a good independent, non-chain transmission shop.
Try the “Mechanics Files” button at the top or
They should give an estimate to inspect or replace the solenoid.

A246E AUTOMATIC TRANSAXLE: AUTOMATIC TRANSAXLE SYSTEM: P0741; Torque Converter Clutch Solenoid Performance

The ECU compares the engine speed with the transmission output speed to monitor torque coverter lock-up. If slippage occurs this fault will set. It may be due to a sticking solenoid or a failed torque converter, usually the latter. The ECU doesn’t monitor the fluid pressure in this circuit so this is a rational fault.

If two shops have identified this as a torque converter failure I wouldn’t be optimistic about a solenoid failure. A transmission shop may be willing to replace the torque converter and clean the valve body, after a diagnosis. This would be far less expensive the installing a remanufactured transmission.

I am still concerned about the transmission fluid. I’m not sure that I trust the dealers evaluation, I suggest that you check it your self. If it is cloudy or any color but bright red, then it needs to be changed. If the ATF has been changed at any place but a dealer, then it is possible that the wrong ATF was used and that could cause the slippage.