165,000mi, automatic transmission. I've owned this car for 4 years, since 126,000mi.
For the past year, this car has been acting strangely, and has been getting stranger. It first started with the brake pedal dropping slightly; braking ability was not affected, but the car has been shifting strangely when parking ever since. The most noticeable thing is that shifting from P to D is delayed by a couple seconds if brake pedal is not fully depressed. Shifting from D to P is rough unless brake pedal is fully depressed. It seems to have a slight loss in power; acceleration isn't as snappy and RPM's sometimes go up to 6 during moderate acceleration (where it would only go up to 3 before). Shifting while driving is generally rougher, especially downshifting, but the car once upshifted HARD a few months ago; it felt like a newbie learning to drive a manual. It's never done that before.
I had the transmission flushed at around 140,000 miles, and the fluid was bright pinkish red when new. The fluid is now orange. This concerns me.

The check engine light came on today; the code is P1717, AutoZone recommended replacing the Neutral Safety Switch. The car has thrown the same code once before; the mechanic said everything was in normal range of motion and just cleared the code. Other codes: 13-13, 11-13, 18-22, and 65-21 (I think this one is old and the mechanic forgot to clear the code). The check engine light turned itself off after running errands for 3 hours. The ABS light frequently comes on during hard breaking, but it quickly turns off. When driving on a few occasions, including today, the D on the dash has flickered erratically; restarting the car fixes this.
I wonder if the car is just quietly eating its own transmission. Does getting a transmission flush and replacing the transmission range sensor sound like a good place to start?

 

Well, good news and bad news. The check engine light is on again and the D light is flashing. Restarting the car stopped the D flashing, but check engine light is still there. Luckily, a relative is going on vacation for a week and is lending me their car in the meantime. Ha ha, convenient!
Thanks in advance!

 

I’d do another transmission fluid drain and refill.

did you DIY the first time around or take it to a shop? Did you ensure to use OEM Honda/Acura ATF-DW1 fluid?

 

Yes, Thoiboi is absolutely correct w/ the OEM fluid. After I had some AT problems, have quit using the M shift option. Just didn't want to stress my AT in any way. Have you replaced your 3rd & 4th gear switches lately ?

Completely off topic, If Joe Namath rang my doorbell, I would strangle him on the spot!!!!!! These Medicaid commercials are killing me, HATE THEM !!!! Cheers

 

Thanks for the replies!
I had the trans flush done at an Acura dealership, and I believe OEM DW-something was mentioned (don't remember exact words said). None of the gear switches have ever been replaced to my knowledge, and I never use the M option.
I'm taking the car in today, mechanic was closed all weekend. The guy I go to now is good, but I'll make sure he uses the correct fluid.

 

Repairs so far: new OEM transmission position sensor and transmission flush with Honda Automatic Transmission Fluid ATF-DW1. According to my mechanic, all 4 wheels speed sensors are dropping diagnostic codes right now. He's going to clear them and test drive the car since it's strange that ALL of them are affected. Can wheel speed sensors mess with the transmission position switch? The ABS issues predate the trans switch issues.

 

Oh my god, the car is beautiful now!I think the transmission range switch had been slowly dying for the past 2 years, possibly for the entire time I've had the car. Everything is fixed; the loss in power, the rough shifting, and even the dropped brake pedal! Shifts and accelerates like a dream now, and it's never been so buttery smooth! Mmmmmmm...
As for the wheel speed sensors, the only answer I have right now is maybe gremlins. My mechanic couldn't get any new codes to appear after the repair, so he cleared everything. We'll wait and see.

 

How old is the battery? The mechanic can check the wheel speed sensor wire harness (or ABS Module, or VSA) connectors and see if there is any oxidation causing poor contacts between pins causing your issue.

 

The battery is 2 years old. I'll ask my mechanic to check the connectors if the abs light comes on again. Thanks!