This is a California car that won’t pass smog tests with a lit check engine light. I don’t know the specific code, but the description is that the torque converter is staying in the “off” position. Apparently the lock up torque converter is part of the emissions system in that if the torque converter does not lock up then the rpm’s are higher and that produces more pollutants.
1st step was to flush out the transmission and the flush made sure all the fluid in the torque converter was removed and replaced. After that was done the trans fluid has stayed nice and clean and pink for about 400 miles. The CEL was turned off after this service but came back on in a few days at about 200 miles. Next, the solenoid that activates the torque converter was replaced. The CEL was turned off again, an this time the CEL came back on after a hour of driving on local errands.
Me and my generally good mechanic are hung up now. We were betting the solenoid change out would solve the problem. Any ideas out there? It seems that the torque converter is in fact operating properly. The tranny shifts smoothly and the rpm’s drop at the proper times indicating the torque converter is locking up.