98' Monte Z34 elec problems HELP!!

With 97k on this car and not one single problem. Then alt goes out, then the battery. I replace them both. Ran great for 3 weeks. One day the Anti-Lock light comes on. 15 min later the Volts lights came on. Then the Airbag light comes on. Then the car will not accelerate and dies. I turn it off and try to start it, "dead". I go to work, 8hrs later, car starts I drive home fine. I had the Alt tested. everything is fine. output = 14.00v, diode is good. Put a OBD II reader on it NO CODES. Battery has 12.00+ volts. Disconnect the Batt and clear ECM runs great for 3 days and starts all over. Any ideas out there? Nothing has been altered on this car whats so ever. No changes.

With 97k on this car and not one single problem. Then alt goes out, then the battery. I replace them both. Ran great for 3 weeks. One day the Anti-Lock light comes on. 15 min later the Volts lights came on. Then the Airbag light comes on. Then the car will not accelerate and dies. I turn it off and try to start it, "dead". I go to work, 8hrs later, car starts I drive home fine. I had the Alt tested. everything is fine. output = 14.00v, diode is good. Put a OBD II reader on it NO CODES. Battery has 12.00+ volts. Disconnect the Batt and clear ECM runs great for 3 days and starts all over. Any ideas out there? Nothing has been altered on this car whats so ever. No changes.

Now there is a error code P0742 = Torque Converter Clutch Circuit Stuck On. From what i've read is a generic error code. any ideas ???

I have had this happen to my moms 92 lumina Euro. The tcc is being stuck on for some reason, either the driver in the PCM is shorted and making it come on or the tcc is sticking in the transmission. The TCC will NOT engauge until there is a steady throutle and the PCM is in a CLOSED LOOP. (Warmed up). It is like stopping a car that is stick shift without putting the clutch in. It stalls the engine. But from what you said it sounds like it is shorting out, causing the car to die and voltage to drop. If it isn't a 4 speed transmission you can unplug the tcc. It will rev about 200 rpms higher when going down the road and a little less gas mileage. But if it is a overdrive transmission a wire has to be cut. But in some transmissions if the TCC isn't engaged the fluid won't cycle thru the transmission cooler and will lead to transmission faliure. I am pretty sure yours is a D 3 2 1 transmission. Check with a transmission shop to make sure about that. Let me know if you need more help with this.

Matt McCain

To see if it is disengaging correctly, try this. When you are driving down the highway, steady speed. Just lightly tap the brake pedal while you foot is on the gas at a steady speed. You should hear the engine rev up a bit and when you release the brake a few seconds later it should kick back in.

Matt