I have a 1999 toyota Rav4 awd automatic with the A540H transmission and have not been able to resolve an issue. The check engine light came on with a P0755 code which is the shift solenoid B malfunction. I know that the 2001 and later models suffered from an ECU issue but mine does not fall into that. Anyhow I have replaced the shift solenoids, the ECU, the trans fluid and filter and thought that it was fixed. I did not rebuild the valave body but thats next on my list but I dont think thats the issue and here is why.
If I put the car into the D position the car shifts from 1 to 2 and from 2 to 3 just like it should. if I have the overdrive on its shifts to 4th and if i turn off OD it goes to 3rd so it seems fine. But if I start in 2nd it will not shift from 1 to 2 at all, i know this from taking it to 5k rpm. I also have no passing gear so if I am driving and put the pedal down the car revs like its in neutral. Now it just revs it does not slip at all and if i let off the gas it goes back into 3rd no problem. I have been looking for answers and have done the tests where I unhook the ECU from the transmission and if i start in 1 and shift to 2nd it goes to overdrive just like it should for the test.
Since this is an ECU control transmission I know it gets info from the TPS and maybe even the VSS but like I said if I put it in D the car accelerates fine and shifts fine minus passing gear. I checked the linkage and since it has never been off dont think it could be out of adjustment as when i put it in park, reverse, neutral, 3, 2, 1 it seems to be fine. I plan to check the electriacl ohm reading from the ECU to the transmission to see if maybe I have an issue there but I am stumped why the engine light keeps coming back on with the same error. I like to think im pretty mechanical and have the toyota service manual but all it says is test the solenoids which work fine. I know toyota has a special service tool that controls the transmission but didnt want to spend the money only to have them tell me something i already know.
I also read about the 2nd gear clutch pack but I would assume that if it was bad that the car would slip when accelerating. So I am at a loss and witts end so any help would greatly appreciated.