My 06 rav4 has a code p0778 which is solenoid b eletrical. I have this problem now for more than a year. Not sure if it's the ecm or the wiring harness to the ecm. I changed the ecm 2 times with used one and nothing. Not sure what it can be.
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This might be helpful check it out: https://www.engine-codes.com/p0778_toyota.html
P0778 TOYOTA Possible Causes
Low transmission fluid level
Dirty transmission fluid
Faulty line pressure solenoid 'B' valve
Line pressure solenoid 'B' valve harness is open or shorted
Line pressure solenoid 'B' valve circuit poor electrical connection
Tech Notes
What does this mean?
When a transmission solenoid is malfunctioned, in most cases the problem is not the electrical part of the solenoid; the problem is foreign material obstructing the mechanical function of the solenoid or the flow of the fluid through the transmission valve body. If the transmission fluid is dirty, it's recommended to change the transmission fluid and if possible removing the transmission pan for further diagnosis. Excessive debris or metal particles on the transmission pan could be an indication that there is a mechanical transmission failure and that the transmission will need to be rebuilt or replaced.
I also forgot to mention that i have changed the transmission as well and still nothing.
My 06 rav4 4 cyl has the engine light on for a while now. The code is p0778 which is from the trans. It's solinoid b electrical. I already changed parts with used ones. I changed the trans with a used one and still has the same code. I also changed the ecm 2 times with used ones. Not sure if it can be the wiring harness to the computer. This problem first started when I changed the battery. It was having issues staring sometimes. I was forcing the car to turn on. Not sure if this could of started my problem.
please don't double post. Thank you.