Contour Enthusiasts Group Archives Forums General Troubleshooting Help with code P0743

prior history


Took car to the tranny man
Got the codes check and came up with this.
P0743 Torque Converter Clutch System Electrical failure.
Can someone tell me what this means?
The guy also said that he was not getting a good reading
on the VSS.????????
He drove the car and he himself is not so sure that the tranny is bad. HE is going to run a pressure test
on it. Do any of you know what the pressure test is? He said that it would tell him if the tranny was good or not.
If tranny is good he is going to start testing the sensors.
If the tranny is bad the cost he gave was close to 3000.00
for new one.Does this price sound about right?

edit: link added.

well for 3 grand you can get your current tranny rebuilt by level 10 with an upgraded and more efficent (and can handle more power) torque converter and other parts that are better. I know you can find remanufactured CD4e's on ebay for 800 or so, and than it would probably cost 800-1200 for labor to get it put in. I think 3grand is expensive for a regular CD4e tranny, however it is brand new. what is the warranty he is giving to you with that?

VSS = Variable Speed Sensor. Basically tells computer how fast car is going to help it figure out what gear tranny should be in.

You don't state the symptoms, but the code is an electrical problem trouble code. Don't believe pressure test possible although flow test thru' atx fluid cooler is, but would IMO be irrelevant unless overheating a concern.

VSS=Vehicle Speed Sensor, there is also a
TSS=Turbine shaft Speed Sensor.

I'd get 2nd opinion before agreeing to any major expense, particularly if car still driveable. Sometimes these elect. problems are transient and resetting computer is all that's necessary. Sensor wiring is subject to moisture, which can cause this type of transient problem.

Cost of installed rebuilds can vary depending on warranty and best to have rebuild provided by installer since labor is major expense if it has to come out to be fixed during warranty period.

EDIT: See later post by unisys12 re pressure test.

i dont know much about ATX contours, but i agree with horseydug on this one. get a 2nd opinion. does the car shudder at all or make any noise on acceleration?

maybe you added bad ATF? that can ruin your whole day.

Is 743 the only code he got?

The TCC solenoid is basically a solenoid body that is mounted on the valve body. It controls a pistion that engages the clutch for the torque convertor. Here is how it works... When conditions are right, the PCM grounds the solenoid, which in turn moves the piston in the valve body into a position that allows flow of the ATF, at a high pressure, to the Torque Convertor. The higher pressure is needed to actually allow the clutch for the torque convertor to lock. Hince the torque convertor locks and does its job. When conditions change, the ground is removed from the solenoid and the piston comes back to its home position and the pressure of the fluid to the torque convertor is droped, hince the torque convertor unlocks.

Now! That said... This thing is not as simple as just a ground. Actually there is no ground present on the terminals. I found all this out here. Pay close attention, because this was a learning experience for me. I found out that 1)my connector was upside down; 2)I have the wrong solenoid body installed in my CD4E (IDIOTS!! )

On to my point, the reason you have a P0743 is because the PCM is detecting a problem with the solenoid body during a self test. The second time it fails the self test, it sets this code. It could be any number of things with the solenoid body, wiring harness or PCM. I don't think you have a problem with anything mechanical or hydralic. If the solenoid is bad... well it is just bad. It either switches or it doesn't. If your TC was locked all the time, your car would shut off not long after starting and if it was not locking, you would see some decrease in gas milage, might find that you have to work a little harder to get up hills and a surgeing feeling. So maybe we can rule out the solenoid itself as being bad. Given that we are getting funky signals from the VSS could be the culprit, but I am not sure because the PCM relies on a combination of information for the Turbine Speed Sensor (TSS), Vehicle Speed Sensor(VSS) & the Throttle Postion Sensor(TPS). So it is possible that some wires have been damaged in someway. Somewhere down the line, the PCM thinks that the information that it is recieveing from the solenoid body is wrong.

Here is a great article that explains in a lot more detail about the use and operation of the Torque Convertor Clutch in ATX's... Torque Convertor Clutch Learning Curve - Sonnax

As for the pressure test... He is basically going to hook up some ports, which are located on the front of the valve body to check the overall condition of the hydralic system. It is a way to see how things are working inside the valve body or on of the many other lines inside the tranny. Look at it like you checking your blood pressure... well sort of!

I hope that some of this helps you out... I am a wordy little bugger ain't I??