O/D CUT1 (No overdrive)

Hey all,

First off, this isn't a Tacoma. It's a third gen 4Runner but the drivetrains are identical so I figure it doesn't really matter that much. I also have a Tacoma which is why I have an account here.

Vehicle information:
1996 Toyota 4Runner 2.7l (3RZ-FE) A340E automatic (2WD)

Driving to work this morning, I noticed the vehicle would not shift into overdrive for the entire 30 minute drive. Same thing this afternoon driving home. I hooked up the scanner and noticed "O/D CUT1" is ON in the computer logic. Does anyone know what the criteria for this switch is? If I could figure out what the computer looks for when deciding to turn O/D CUT1 on or off, I could troubleshoot what's going on.

Some other related notes:

• The only DTC present is for O2 B1S2 (after the catalytic converter). This code has been present for years with no issues.
• TPS % signal is active and accurate
• Engine coolant temp signal is active and accurate
• Both VEH SPEED and VSS signals are active and accurate
• O/D CUT2 toggles on and off with the "O/D OFF" button on the side of the shift lever
• Kickdown switch is accurate
• TCC (Lockup solenoid) is functioning. It will lock the torque converter in 3rd.

Any help would be appreciated. Thanks.

Below are photos of the scanner with some data screens:

 

Maybe its just a brain fart.....

No overdrive | Tacoma World

 

Next guess is that overdrive solenoid is stuck in 'OD off' mode.....

theres an old tacoma world thread that discusses that solenoid getting gummed up over time....
and super expensive to replace.....$400 last I checked on my 43d tranny....and like only one of them in the country.....without going the Dubui route....


I'll search for that thread when I get in from work.....

 

The computer wont allow upshifting if certain temps are not met, there should be two temp sensors on the water manifold, one is for gage indicating the other is for ECU monitoring, if temp is not high enough it wont allow upshifting, suspect ecu temp sensor.
R/
Andy

 

So to provide some closure to this, the issue fixed itself. I did disconnect the battery for a few minutes as silver taco suggested, but when I checked on the scan tool directly afterwards, O/D CUT1 was still on. I let the vehicle sit for a day, and the next time I drove it overdrive was working as normal. I'm not sure what caused the issue.

 

Yeah about 10K ago.....mine down shifted to low to pass.....and would not upshift out of 2nd....

So limped to a parking lot......popped of neg clamp for a minute.....

Started right up and drove away normal.....

Its never happened again.......


Thats when I poked around and I found about that overdrive solenoid getting stuck later in life....
seems if you leave the OD on all time......and never using it will prevent it getting stuck in permanent OD off mode......

In other words 'you should never use the OD off function unless you really need it'...could get stuck that way......

 

Another update: O/D has been intermittently cutting in and out. I believe that it is a faulty input to the ECU; one that the ECU bases the conditions for an overdrive shift on. Going to download the wiring diagram from TIS and go through each input to the ECU to see if I can find anything abnormal.

 

Looking at the wiring diagram for the O/D circuit when you push the button it goes to ground and the light comes on. The ECU is tied into this circuit how does momentarily going to ground lock O/D off and on? Please help explain how that works! And does the engine need to be at a certain temp for O/D to turn off when button is pushed?