What's wrong with my A343F Transmission? (17 Viewers)

[Malleus]

That'll do it.

 

[Eyedaho]

Ok, so here's the update so far and the order in which I've done things. I figured the ECU problem might be the issue after malleus suggested it, but I wanted to check everything else first.

I tested continuity to the solenoids and couldn't find any damaged wiring anywhere near the transmission. So, this doesn't seem to be the root of the issue.

Then, I decided to see if there were any codes. I realized that I had never seen the check engine light in the life of the vehicle, so I didn't think this would do anything. I could not turn the diagnostic mode on (engine light should flash) on or turn the engine light on.

Some YouTube results showed that I should have seen the light turn on every time I started the car, but this has never been the case. So, I removed the instrument panel and checked for burned-out bulbs or nefarious previous owners. Nothing found.

Some googling about why dialogistic mode and/or the check engine light not working pointed potentially to the ECU and leaking capacitors.

So finally, I pulled out the ECU and found leaking capacitors (pictured, see the top right and bottom left). Now, I wait for a hopefully good second-hand ECU to show up and resume the repair.

View attachment 3819706

Capacitors are super cheap and easy to solder in if you want to go that route too.

 

[OBANGR]

Capacitors are super cheap and easy to solder in if you want to go that route too.

I have such sudden downshift issues in my 1st gen sequoia, can this be the cause? no error codes on scanning