I recently acquired a 2014 ES350 (high mileage) and experiencing an intermittent transmission slip.. The check engine light did come on with code P0990 "Transmission fluid pressure sensor/switch E circuit high". Can anyone advise of what steps I can take to check or is the transmission toasted at this point?

 

How high is high mileage?
The "circuit high" usually means an open circuit possibly caused by a broken wire or other fault. The TCM is mounted directly to the side of the transmission so the problem is likely internal. The pressure switch is on the valve body inside the transmission and connected to the TCM with an internal wire harness. A good transmission shop should be able to diagnose the problem and replace the faulty part. Lexus/Toyota dealer service will likely want to replace the entire transmission.

 

Mileage is 273k. Lexus already tried to sell a transmission for $8,800+tax... hoping there is a better solution.

 

Should be several other alternatives. 1. Replace valve body with a refurbished one $200-300 plus labor 2. Replace transmission with used one $2,000 -3,000 plus shipping and labor. 3 Rebuild your transmission $?
The valve body can be changed without pulling the transmission out of the car, so labor charges would be minimal, but with your mileage a replacement or rebuild would be a better long term solution depending on how long you plan to drive the car.
Since your car is apparently still drivable Id suggest taking it to some local reputable transmission shops for quotes.

 

Try a transmission fluid change, there’s many a thread on the topic. Some opinions are dead against doing such a thing, claiming it’s lifetime fluid. In fact it’s reported that some Lexus dealers refuse to do it. I for one don’t believe the lifetime fluid claim. I had my ‘14 ES 350 trans fluid replaced at a Toyota dealer a year ago after experiencing some mild lazy shifts. No reoccurrence of that, and it’s running fine. The $270 (CAD) I paid is a small expense compared to a new tranny. Could be worth a try.

 

I would 1st do as mentioned the drain and fill, with Pan drop and new filter. If that does not work I would source from Car-parts and/or other a low miles Tranny. My friend had to put one in his 2014 about 3-4 years back. Only had 90k on it. The Tranny was only about $750 from a 18k miles wreck. Not such a tuff job either with Front wheel drive.

Normally the internal repairs of valve body and other don't resolve the issues. Whatever you do, just don't get a fluid machine Flush.

 

So I was planning to have the fluid changed and possibly replace the valve body, upon scanning codes again there is also a P2757 "torque converter clutch pressure control solenoid-control circuit performance or stuck off". To me, sounds again like a valve body concern but would like opinions. It is much more feasible to replace the valve body than the transmission but just wanting to make sure this isn't some kind of known issue where there is a known solution. Thank you in advance.

 

At 273,000 miles I would advise either a rebuild or another transmission from a wrecking yard. You can attempt a filter change, along with a drain and fill (only changing fluid that was lost). I am pretty sure your codes are being caused by dirty solenoid contacts. When you change the filter/fluid, the new fluid will start cleaning the internal parts. Another fluid/filter change may be necessary. It has happened to me in the past.

I will be very surprised if this original transmission life can be extended unless it has had regular fluid changes in the past. It will not cost much to try the filter/fluid change to see.

 

My 2013 does not have a Transmission dipstick. How do you fill it up after you have drained it?

I changed my 2006 Avalon with Valvoline Max Life. Runs like a dream. Dropped the pan and replaced the filter, and disconnected the trans cooler line outlet and drained the cooler by running for a few seconds then filling up the transmission again. Did this several time until the outgoing fluid was clean.

But I had a dip stick. So again I ask how do you refill it?

 

 

I had no idea Weber University had these YouTube Videos. Weber is 12 miles away. My youngest son received his Associates in Mechanical Engineering and his MBA from Weber. This is a great resource. Thanks again.

 

Hey danny,could you help me with p0990 with my lexus 2014 how fixing it 🙏

 

I will agree with what others have eluded to in the thread: If you have 273k miles on that tranny, you're better off replacing it with a lower-mileage used one from somewhere else. You could try to do a flush, but if it's never been serviced before, you're introducing more problems at that point. Drain-and-fill, and flushes only work well if they are done at regular intervals (every 30k-45k miles).