2003 Bonneville SE Torque Converter Clutch Solenoid

[Jaxstarke99]

Hi guys. New member here. I just spent $400 replacing the torque converter clutch solenoid in my 2003 Bonneville SE after

the Service Engine Soon warning light came back with a P0742 code (Torque converter clutch solenoid stuck on).

The repair didn't work. The transmission is still trying to go from first to third or fourth gear and won't downshift until

you nearly come to a complete stop and shifts really hard when it does decide to switch gears. I'm at a loss

as to what to check for next. Any ideas? Thanks.

[MKMike]

Welcome to the forum.

Did you go to a transmission shop and ask them to replace the TCC solenoid or was that their own diagnosis and recommendation?
If it was the latter, I would have them tell me why the transmission isn't working properly and the code is still setting.

There can be different causes, such as the 20 pin connector at the transmission, corrosion or poor contacts, detailed here in a TSB posted by Archon http://www.pontiacbonnevilleclub.com/fo ... ilit=p0742

IIRC, there have been instances of the issue being caused by the connector getting pulled on because of a bad transmission mount, causing contact problems.

The Factory Service Manual tells technicians to:

Inspect the connectors at the controller, the component and all other circuit connecting points for an intermittent condition. Refer to Testing for Intermittent and Poor Connections in Wiring Systems.
Inspect the circuit wiring for an intermittent condition. Refer to Testing for Electrical Intermittents in Wiring Systems.
Rapid fluctuation in line pressure could set DTC P0742.
An open condition in the TCC release circuit or switch would set DTC P1887. Open circuits are not diagnosed in DTC P0742.
Inspect for a pressure regulator condition.
Inspect for abnormal line pressure.
The customer may notice an engine stalling condition.

Let us know what the findings are.

[Jaxstarke99]

Thanks for the reply and suggestions MKMike. I took the car to Autozone after the car had been acting up and the Service Engine Soon light came on and the code came back P0742 for tcc solenoid stuck on so I just told the mechanic that and that's what he replaced. It drove fine for a few days of short (3-4 miles) back-and-forth to work driving but I took it out for a longer drive (40 miles one way) and it went back to doing the same things about 30 miles into it. I told the mechanic about it and he said they'd check the pan to see if there is anything in the trans fluid that might be clogging up the solenoid but I haven't had the chance to get back out there yet. I'll check the 20 pin connector and wires myself tomorrow morning and hit it with some electrical contact cleaner to see if that helps. If I have time I may head back to the mechanic again as well. Thanks again.