I have a 99 ram 2500 4x4 w/5.9L, I got a check eng. light and read the codes and got a P0138 which is a O2 sensor circuit high voltage bank-1 sensor-2 and the second code I got was a P0740 which is a torque converter clutch circuit malfunction. Now the ques. I have is, where do I start to fix this prob? I imagine replacing the O2 sensor after the cat might take care of the sensor prob but with the torque convert circuit malfunction I have no idea where to start with that. If anyone could help me out with this I would appricate it. Thanks..................

 

to start out, drop your battery cable off for 15 or 20 mins(just to make sure) to clear the trouble codes....see if they turn your light on again, could just have been a misread....

 

O2 sensors shoot codes for a couple of reasons, 1 they'er bad 2 your motor is due for a tune up and it is giving a bad 02 code. If you disconect the battery for 5 min you need to drive it for 60 miles that resets it and if the problem persists the light will come back on. If your motor was out of whak tune up wise and it shifted at all funny that would set the tranny code. if your motor was out of whak you should have retived P0300 codes for spark issues if your cat is bad that can give O2 codes and if it is chocking your motor to make it shift hard that would send those codes too.

 

you can also clean them. I've fixed a couple of o2's that were throwing codes. CRC electronic parts cleaner will do the trick.