Last week my daughter's '05 Accord had error codes P0780 & P1731.
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I checked the trans fluid. It was at the right level but looked dirty.

I changed the transmission fluid and drove the car. It seemed fine again. This morning she went to drive it and started having shifting issues again.
Now it's showing error codes:
P0780, P0796, P1733

Error codes

i couldn't change the filter because there were none available anywhere near me. I need to order it.

​​​​​​What else do I need to do with this? Is this replace or clean the pressure control C solenoid? Or, is there something worse?

 

I think the filter is internal on that transmission where you essentially have to disassemble the transmission to replace. Does your accord have an in-line external filter?

When you changed the transmission fluid, did you do just one drain/refill? Each drain/refill takes ~3 quarts.

For the solenoid, you can try removing and cleaning any debris out of the solenoid. I don't know how difficult it is to access. You can also try supplying power to the solenoid to listen for a click.

 

Thanks for the reply.
Yep, it has an inline filter like this:


I did one drain/refill because I figured I needed to drive it a little to help clean out any dirt & debris that may have accumulated and blocked any solenoid screens from the 1st set of error codes. I planned on doing it again when I get the replacement filter this week.
I just don't know if it's just the "C" selenoid or if I have to worry about all of them.

 

I think the B and C clutch pressure solenoids are one assembly, so you can remove the solenoid(s) and look for any obvious debris that can cause your issues.

When you drained the trans fluid, did you see any metal shavings in it? To exchange most of the fluid, you should do 2 more drain/refills. Just do some driving in between to mix the new and old fluid.