Expert: Roland Finston - 1/8/2012

Question
obd 2 scanner gave me a reading 0743 torque converter circuit on my 1995 dodge neon. Where is the location of this torque converter circuit and what is fix to remedy the problem. thank you very much.

Answer
The torque converter clutch is operated by an electrical solenoid which is attached to the valve body inside the transmission. The solenoid is activated by the powertrain control module by its grounding an orange/black wire that connects between pin 17 of the pcm plug and pin 2 of a three pin plug located on the side of the transmission that faces the front of the car, at the forward end of the transmission near the bell housing for the torque converter. You will see the wire harness that goes to it on that side of the transmission which faces the front of the car. The circuit is basically a 12v supply from fuse 10 (which powers many things when the key is in the run position) to the solenoid on a light green/black wire to pin 1 at the solenoid plug at the transmission. When the pcm grounds pin 17 the solenoid is activated to lock up the torque conveter input and output turbines.
Does the engine refuse to turn over, which may be due to the converter being locked up when it shouldn't be (similar to trying to start a manual transmission while in gear with the clutch pedal released), or does it turn over fine but just won't start?
If it is locked up, then either the wire from the clutch plug is shorted to ground all the time (mesure whether that is true with a volt-ohm meter or a continuity tester between the orange/black wire on pin 17 and ground), or the solenoid is stuck in the closed position (which probably means that the valve body should be removed from inside the transmission and the solenoid be replaced.
I don't specifically have the troubleshoot for 0743 code but that is what I would believe that it is about.
Roland