High Rpms/Trans Problem

2001 Tacoma 4x4, truck shifts fine through 1st and 2nd gear. 3rd to 4th shift around 3,250 rpms and drop to about 2500 rpm. 4th gear will Rev to about 3500 rpm and at torque converter lockup will drop to 3250 rpms at 55mph. Truck was throwing shift solenoid E code so I replaced all the solenoids only for the code to be thrown again. Any ideas as to what it could be would be causing it to Rev so high would be appreciated

 

@gearcruncher might be able to help

 

This^
Also look here.

 

my car with the same 30-40le trans did that till i plugged in the sensor on the side of the transmission that throws your reverse lights

 

Thanks for the link, looking at the threads about it possibly being a torque converter for the PO770 code. Not completely sure at this point

 

Possible faulty wiring from the solenoid going up to your ECM .
If the code is still popping up , you will need to do a resistance test with an ohm meter to verify the wiring is good .

 

All plugs are in correctly, didn’t notice any connectors loose either

 

Resistance test on the solenoid?

 

Yes sir , you replaced the solenoids , but is the wiring good going up to the ECM . Its not uncommon for a wire to ground out after 17 years . Another issue is corrosion . Corrosion occurs at the wiring harness going into the transmission .
The computer in your truck commands the solenoid to energize , but the ECM doesnt hear a reply from the solenoid .
You need an ohm meter . Then disconnect the wiring harness up at the ecm and verify proper resistance .
There is a file at the bottom of that link that was posted above called ATSG service manual .
You will need to grab that file . It will tell you the resistance values of the solenoids and how to test them .

 

Will do,thanks for the response

 

@gearcruncher . I have an ohm meter to test the resistance at the ECM but I can’t seem to find anything that directly tells how to test it at the ECM. The ATSG service manual shows how to test the “Neutral Start Switch” on page 77. This seems to be the only thing in the manual about testing the solenoids at all. however you said it needed to be tested at the ECM behind the glove box? Is there possibly any diagram or write up that shows how to test the ECM directly for these solenoids? After doing some more test driving is seems like the torque converter isn’t locking up at all and that’s what is causing it to stay at high rpms at highway speed in overdrive. I believe it may be the wiring from the ECM to the lockup solenoid.

 

Hey Jacob
I need your engine size to properly identify your A340 series transmission.
https://atsgmembers.com/transtype/
How many solenoids did you change ?
Do you have a factory repair manual for your truck ? We will need to use the manual for specifics
The lock up solenoid is known for issues . The Atsg overhaul manual shows 11 - 15 ohms for the solenoids on page 77 .

 

It’s the 5vzfe V6. I changed the 3 solenoids you get direct access to after dropping the trans pan , and no sir I don’t have the repair manual. I believe the trans is the A340F. The ATSG website doesn’t have specifics for “3.4 4WD” so I assume all 4WD are the a340F?

 

How long has your truck been throwing the code ?
P0773 Shift Solenoid E Electrical

If anyone reading this has a factory repair manual for a 2001 Tacoma , please pass it on to Jacob . The one I sent him is all broken up .

He needs to trace the wiring back from the lock up solenoid going up to his ECU .
We need to know what ecu pins to backprobe for resistance values

 

It’s throwing P0770 for shift Solenoid E, been throwing it ever since I got the truck. Dude that sold it to me took the bulb out of the CEL and I didn’t have an OBD scanner at the time so I’m assuming it’s been throwing it since the last owner had it.

 

Ahh crap . P0770 is not a fun code to work with .
I would have preferred P0773 .

How many miles do you have on the truck ?
Has the transmission ever been replaced ? I can imagine she enjoys drinking fuel with that code

After we double check the wiring for P0770 , you are looking at this

https://www.tacomaworld.com/threads/sonnax-zip-kit-a340-late-installation.435019/#post-14714790

 

Jacob , check your VIN #
Then read the TSB below

 

The odometer says 120k although the Carfax shows it has been rolled back quite a bit at some point. Probably somewhere around 180k is actual miles. I don’t think the transmission has ever been replaced. Yeah and drinking fuel might be an understatement lol I maybe get 14 mpg on the highway. Like I said the rpms stay around 3k at highway speeds. I will check the VIN and look at the document you sent soon and reply back

 

Every digit in the “effective VIN” in the document you sent for the Tacoma v6 is the same except for the 3 at the end

 

Alright .

When you clear the code using your scanner , does the code come right back ?
Lets say you go out to the truck now and P0770 is stored in memory .
With the key in the ON position but the truck not running , try clearing the code .
Then turn the ignition off .
Now that the ignition is off , turn the ignition back to the on position but dont start the truck .
Did the code return ?