P0755 out of nowhere

[mrHUGE]

No Overdrive!

I just bought my 2001 4Runner 3 months ago from a guy who took great care of it and it has just over 103k miles. I was driving on my lunch break when I noticed I was at 2500-3000 rpms going 60 down the highway. I stopped at a business and started her up again and once I went back on the highway I greeted with my Check Engine Light. I promptly had my code read (P0755) Solenoid "B" Malfunction. This occurs with 2 trip logic and it is tripped by the ecm knowing the transmission is not in the gear it should be. I have replaced the solenoid with no success. The pan was pretty clean when I pulled it off. My next suspicion is the ECM. The transmission has shifted perfectly at all times during my ownership. The manner of which this problem "clicked on" makes me believe it is an electrical problem.

Here are my questions:
While driving, I can feel it shift 3 times hence I should be getting in overdrive correct? When I let off the gas, the RPMs will drop to 1k but ramp back up to 3k when applying gas. Am I in Overdrive? What is going on?

Does anyone have any other suggestions of what might be going on? I have recently added an external tranny cooler (2 months ago) and a CD receiver (1 month ago). Are there any wires I could have loosened in the center console that are related to this issue that finally lost their connection?

 

[mrHUGE]

Ok, more on the issue. I have been tearing through the FSM looking at how I should go about fixing this. I have found the pinouts for the ECM and I am getting correct voltages for all solenoid circuits from the ECM. It looks like I need to investigate the valve body next. Are their any suggestions for what is going on otherwise that might be good to check before going through the work of dropping the pan again? Also, I noticed while driving the 4R 50mph with O/D off, the RPMs drop to 1500 when I let off the gas, but if I have the O/D switch on, the RPMs will drop to 1000. Is this normal? Is this the torque converter functioning even though O/D isn't engaged?

 

[mrHUGE]

More on the topic

So I've been reading about all I can find on my issue and it looks like I'm going to check the valve body out this weekend. I'm going to specifically target the area from the line feed to the top of the 3-4 shift valve and the channel that pressurized my OD Brake.

In regards to my previous post, the torque converter is engaged in 3rd with O/D off so it runs at 1500rpm when I let off the throttle. When I switch OD on, the torque converter only locks in O/D so therefore my engine drops to 1000rpm.

I hope this will be the end of it.

 

[gmason6261]

p0755 issue..

I am currently having the exact same problem to the T ...
what exactly did you find out and how did you go about fixing the issue..

 

[andrew0929]

Same Problem!

Hi
Any news on the results because Im having the same exact problem.