I have a 2000 Jeep Cherokee Sport with ~210K miles on it. I have been getting a P0740 code for the last six months. The Jeep drives and shifts fine. Alas, I have to pass emissions so I have been trying to get this code to clear. I have drained the fluid in the pan and changed the filter. I have pulled the solenoids and checked the resistance (they all showed 15 ohms). I have checked the wire harness for the solenoids above the transmission for issues. So far everything has checked out fine. I am really beginning to struggle with what to check next. Any and all advice would be wonderful. Thanks !

 

When I first bought my 99 (223,000 miles) it was doing the same thing and I did the same stuff you did to yours but after changing the fluid 3 times and driving it for about 2 months it stopped throwing the code.Make sure your fluid is as clean and as red as the fluid is when its new in the jug.

 

Your tranny have overdrive? Does OD seem to function properly? Get up to 50+ mph and turn OD off (if possible) Then w/o letting off the gas, lift up on the brake pedal. You should feel the TC unlock or lock if the brake light switch is adjusted properly. The brake light switch affects OD on/off as well. You can check it the same way. My '93 had a similar issue that turned out to be a bad brake light switch. It didn't throw any codes tho.. just a thought

 

Not sure about older models but I know on my 99 you leave it in OD and you keep on the gas and push the brake peddle down to unlock the TC,your rpms should go up when applying the brake while holding the gas down.

 

Do this ^.

One of the first things on the diagnostics list is to check the brake switch.

This will tell you if you are actually going into Overdrive. Solenoid C could have good resistance but if the brake switch is bad the trans will not go into OD.

The brake swtch is not adjustable, and if defective, must be replaced.

 

Thanks for the ideas. I will check to make sure I have cycled all the old fluid out with another drain and fill. Also I will check the brake switch next.

 

I just wanted to post a final result on my issue. After cycling the fluid again. I went to take it out for an O/D test run and when I started the jeep the CEL was off. I drove it straight to the emissions testing center and passed. Thanks for the advice, so far so good.