Shifting Related Check Engine Light

2015 Toyota Sienna Limited AWD model
Symptoms in order of appearance:

1. Upon lifting the throttle while driving around town, a rapid clicking sound is heard. Pressing the gas causes it to stop. It seems the rate of clicking is faster with speed, but with 3 women all talking in the car I was unable to really hear it.
2. Driving longer distance (to home), vehicle shifted into neutral when accelerating from a stop, not sure of which gear shift was missed. Lift of throttle, and it shifts into gear and continues normally
3. Babying it now...on highway, light accelerating after slowing for traffic, occasional hard shifts
4. Stop to gas up, no leaks seen under car, slight oil shown leaking from engine pan. Dipstick seems to get covered in oil as you move it in and out, unable to get a good read.
5. Dried coolant seen on area around cap, but it's hot and we're moving so I don't try to open it. I haven't opened the hood in probably a year...no idea how old this residue might be.
6. Same as in #3, more missed shifts, have to go REALLY light on the throttle to get it to shift. Again, it's hard to tel when this thing shifts at low throttle, but I suspect it's the 2nd to 3rd shift...
7. Engine light comes on, traction control is turned off, dash indicators show ONLY the front wheels are applying power.

Note the coolant temp gage on the dash was right in it's typical normal temp the entire drive. I had no other trouble code lights.

Diagnostics done so far this AM:

• Trouble code F07933
• Check coolant reservoir empty and dry
• Check under coolant cap, no coolant visible
• Check under vehicle for leaks on cardboard put out yesterday, no drips

Late December work on my own:

• 2" Traxda Lift kit installed on all 4 corners

Wheel works: 12/26/23, 113,028 miles:

• New Tires installed (went up one size)
• Alignment done, shop indicates front control arm bushings need replacement (maybe from install of lift kit? Over torqued them?)
• Bouncing at highway speeds started...
• Installed TPMS sensors that had failed, and rebalanced tires
• Still have bouncing on highway, but realize it's intermittent. Perhaps the front bushings?

2 weeks ago, 114,585 miles:

• Oil Change done.

I would have thought checking the coolant would be included in an oil change, but this was done by Wheel works, and I checked my invoice, they didn't list any checks.

I'll have to add coolant next.

Any recommendations on what to check next? I wasn't able to find a transmission fluid dipstick under the hood.

Trouble code was wrong. I have two DTC's:
P0793
P0793 P

P0793: Intermediate shaft speed sensor A malfunction.
It appears that service of the intermediate shaft speed sensor requires removal of the valve body from the transmission.
If you have a scanner that displays transmission data, you may be able to watch that particular sensor on a test drive, but the computer has all ready flagged it as a problem, so I wouldn't be surprised to see it acting irregular. If you have a scope, you could scope the speed sensor, but again, with that code, I would expect it to be irregular. Really, all you're left with is to check the wires from the transmission to the computer for chaffing or poor connections. Anything else must be done inside the transmission.
 

Thank you - I've picked up the manual from an ebay seller. It's likely either the sensor itself or the transmission control unit. I don't want to break open the transmission myself so I'm going to bring it into a shop. I don't have any of those scanning tools.

Definitely start with a transmission fluid level and condition check. The level gets checked with the standpipe in the transmission pan at 104 - 113 degrees fluid temp. If you find a bunch of metal or converter material in the fluid sample, stick a fork in 'er.

1. Upon lifting the throttle while driving around town, a rapid clicking sound is heard. Pressing the gas causes it to stop. It seems the rate of clicking is faster with speed, but with 3 women all talking in the car I was unable to really hear it.

With respect to 'Wheel Works' or whoever, but the sound you're describing is classic loose wheel. Check all the lug nuts before you go on another test drive.

Thanks Tyler for the response. I've checked the wheel lugs and they're all properly torqued. I think I'll bring it in to do the rest of the checks.

Updates on the van.
1. Toyota dealer service person they put between customers and the mechanics meant this was a wasted $200. He's also terrible at his job. He apparently did not write down the symptons I told him about, and only told the mechanic things I did NOT say (that another shop diagnosed the transmission as bad).
2. Toyota dealer master technician, is good at identifying obvious things that need fixing, but couldn't find any concrete things that point to the transmission being a problem. And apparently he was unable to replicate any of the symptoms.
3. Driving away from the dealer, the clicking noise was obvious upon lifting of the pedal. I was able to determine that the noise gradually fades, when you shift into neutral. i also confirmed the noise doesn't change when you press the brake pedal (since the dealer was telling me it was the brakes). I went back immediately, told the service writer the noise was happening right then, and he wasn't interested in talking with me. Told me to come back any time if I want them to look at it again, told me it was the brakes, and tried to show me a model of a brake caliper.
4. New symptom, when shifting into reverse, nothing happens about 50% of the time.

Bringing it to a trnasmission specialist shop next week.

Transmission shop said it needed a replacement transmission. That this one is the worst transmission design from Toyota - it has a design flaw that causes case wear, which sends aluminum throughout the transmission. By the time I got it to the shop, I was stuck in 2nd gear only.

$8000 or so, for the replacement plus replacing both front lower control arms whose suspension bushings were torn and ready for replacement already at 115,000 miles.

CA location

Wow, that sounds pretty heavy. I never spent $8000 to buy a car let alone fix one.
Best of luck to you

Yeah vehicle costs are skyrocketing. Even used are still expensive. The clutch replacement and other items while they were in there on my 2004 civic si back in 2022 was $3000. The dealer is asking $64k for what would be a used 2023 replacement Sienna Platinum. And I really like my Sienna, it is what I want for comfort, transporting my sports equipment, and for road trips. I drive smoothly and don’t have a heavy foot so it suits me. I already added a lift kit and just put good tires on it in the last 4 months. It’s ready for a road trip. I pick it up today.

Well, at least you got your ride back in action. All up from here