How I resolved OBDII Code P0740 on my 2000 Honda Odyssey

Sat, 04/17/2010 - 02:18 |

admin

I have a 2000 Honda Odyssey that was having trouble shifting from lower gear to higher gear. Usually, it happened from 2nd gear to 3rd gear but occasionally happened from 1st to 2nd and 3rd to 4th. When this started happening, it felt like the van just wouldn't shift to the next gear and it would also rev high without shifting. Suddenly, the CEL (check engine light) came on. So I took it to AutoZone and they plugged in an OBD2 diagnostic tool (error scanner). It gave an error code P0740. They looked it up and it had something to do with the TCC (torque converter clutch). I couldn't believe this was happening! I had just bought the van a day ago from when it threw the CEL. I was in a panic. I called the mechanic who sold it to me AS-IS and asked about the problem. He couldn't give me a straight answer. :(

So I went on-line and researched this issue and found out that there were/are tons of people having the same issue with code P0740. In my research, I also ran into a website that was some kind of law suit against Honda for this very issue. The website is http://www.hondatransmissionsettlement.com. I read through all the documentation on the site but there was nothing that showed me how to fix my problem.

Feeling frustrated about this issue, I took it to an Authorized Honda Service Center. Before they can even look at my van, they made me agree to a $98 diagnostics fee. What other choice did I have if I wanted them to look at it? So I signed it. A regretful idea! Basically, all they did was plugged in a scanner just like AutoZone did and told me the same error code P0740. They also told me that it would cost me a little more than $3900 to replace the transmission and that that was the only way to fix the problem. I told them that I am entitled to a free repair according to the Supreme Court Settlement ruling (from the site I mentioned above). They called Honda Corp to try to get approval for the repair. Of course, Honda Corp turned it down because I was not the original purchaser of the van. :(

To say the least, I was feeling quite uncomfortable with all of this. But instead of just throwing the van away or selling it as junk, I tried to fix the problem myself. I'm not a certified mechanic but I am pretty handy with a wrench. :) From my research online, some mechanics were saying that it could be as easy as replacing a failed solenoid. So that's what I set out to figure out.

AT Solenoid There are about 6 or so solenoids on the transmission. I started with the most obvious solenoid which is called the AT Shift Solenoid. It was located on the upper side of the transmission directly under the throttle body intake valve. There's not much room to work around the solenoid so hopefully if you are going to do this, you should have the right tools. I used a 6 inch or so 10mm monkey wrench. I had to remove the air intake tube and airbox cover to allow somewhat more room to work around. After about an hour or so of fiddling around with taking the 3 bolts off of the solenoid, I was finally able to get it off. When I looked at it, the 2 screens were dirty especially the round one. I sprayed some carburetor cleaner on them and used some Q-tips as well. Now, they look very clean! Look at the picture I made. I installed everything back and resetted the ECU. Afterward, I took it for a 30 minute drive around town.

WOW!!! There's no more hesitations with shifting and no CEL either! It drove just as good as when I test drove it at the time I bought it! To think that the Honda Service Center was going to charge me almost $4K to replace the whole transmission, I really feel relieved that I didn't get ripped off more than the $98 they charged for diagnostics! WHEW!!!

If you found this article helpful, please let me know. Thanks! :)

This article was also posted to: http://www.odysseytransmission.com//ProblemCases?msgId=357

Comments

Submitted by admin on Mon, 04/19/2010 - 05:11.

Here's an update...

I drove the van for approximately 80 miles. It drove perfectly until one point after that, it began to give hints of the shifting problem although it was not as bad as it used to be before I cleaned the A/T Shift Solenoid screens. Also, the CEL came on shortly thereafter. I took it to AutoZone again and they said it was the same error code P0740. Of course, I expected that.

Even with the CEL on, it was still shifting pretty good with very little hints of hesitation which only occurred while shifting from 2nd gear to 3rd gear. Like I said, not too bad though. I suspect that the ATF (automatic transmission fluid) still has some "crud" in it; and probably that "crud" is getting caught on the screens gradually.

The next thing I will do aside from cleaning the screens (again) is to change the ATF. I read that my Odyssey holds about 12 quarts of ATF and that I am only able to drain out about 3 1/2 quarts each time. This means I must continue to change out the ATF about 7 times (each time after 30 minutes of driving) until it is flawlessly clean.* I may need to go through about 20 or so quarts of ATF, but hey it sure beats paying $4K for a new transmission especially knowing that my transmission still works fine so long as the AT Shift Solenoid screen is not getting clogged up!

*SIDE NOTE: According to the pro's, changing the ATF in this manner should be the only way to clear it up because getting a "flush" can potentially screw up the transmission completely! I also read that ATF should be changed once every 25K to 30K miles on Odyssey's. Whether this is true or not, it sounds plausible.

As painful as this all might seem, I guess it's worth rescuing my van from the junk yard! Anyway, I will update again after I have cleared out the ATF as mentioned above. Until then, drive safely!