Mtdave2

Long time trying to trace down the reason for this code, 95 ls400. done all the usual stuff, and more. System is new from ECU to solenoid, every wire and plug. odd in itself to still have the issue. .

Here is the truly odd part, If I clear the code with the motor over 2k rpm, either in the drive way, or driving down the road, the fault disappears, for as long as it is held over 2k. The moment it drops under, blamo....code is back.

The lock up will work perfectly going down the highway with the code cleared. will go in and out of lockup. so, scratch your heads and try to think of a scenario where that makes any dam sense...

djamps

Line pressure issue? Did you clear the screen and replace filter?

Yamae

Does the AT really have a separate screen and a filter?
As far as I have seen, there's only a mesh filter so called a strainer.

1uzLexzeus

maybe one of the new parts is faulty?

Mtdave2

how would line pressure cause a fault? do your cars fault out when you just turn the key on? 3 sensor tried all do the same thing. yes the screen is clean.

damon

http://www.sonnax.com/parts/4287

Mtdave2

well it shifts fine, seems to have enough pressure...

Mtdave2

now that it is spring, time to start working on this project again. Still can not figure out this odd problem.

Mtdave2

Can anyone think of a reason that would explain the code tripping under 2k rpm? I drove this rig 2000 miles last fall on a road trip, it preformed perfectly, except for the fact that I had to clear the code out every time i dropped be 2k. lock up works fine, shifts fine, runs great.....wth!

Mtdave2

I guess I should point out that this is a 91 toyota rv that I swapped in a 95 ls400 engine, trans, gauge cluster, and ecu. A few of the systems from the car are not connected in the rv for obvious reasons and shouldn’t cause an issue but hell at this point I am looking at everything. Trac-contol, aba, and all sort of small things. the cruise control is hooked up but not working yet.
Just to be clear:
• After rev past 2k and clearing the code, it will not code again, and the lock up will function perfectly.
• Once cleared, drop below 2k, codes
• Clear code and shut off engine, turn key to on (not staring the engine) it will code.
o This to me rules out line pressure, TC, because it codes without the engine running. And the code is electrical.
• I have tired holding the pedal to the same position that revs to 2k. Does not seem to be related to the issue.
o Unplugged TPS, tried again, no change.
• I have disconnected the alt and tired again thinking perhaps the rev got more votls,,?? Had no effect.

dicer

You can help eliminate some of the guessing by hooking the car up to a good scan tool that will see and control that solenoid. If it sets a code just turning on the key then the ecu is sending some signal out and likely not getting the correct reply back. Unlike the gen 1's I think there is more intercommunication between electronic control modules in the gen 2's so its very likely its putting a call out to a module and since its not talking back the main ecu is setting the code. And it maybe some programming error from the factory that sets that particular code. Have you searched any technical service bulletins for that code? You can find them at that Toyota site, or maybe even go to a dealer and ask to see them.

aptoslexus

Don't know how a 95 differs, but this is how a 98 works. The ECM doesn't seem to like whatever you've patched together. Maybe a TPS issue?

SYSTEM DESCRIPTION
The ECM uses the signals from the throttle position sensor and
Air−flow meter to monitor the engagement condition of the
lock−up clutch.
Then the ECM compares the engagement condition of the
lock−up clutch with the lock−up schedule in the ECM memory
to detect mechanical trouble of the shift solenoid valve SLU,
valve body and torque converter clutch and automatic transmission assembly.

Mtdave2

Great input guys thanks. I will search for bulletins. What the ecu isn't seeing it is seeing above 2k rpm. What happens at that point that isn't under 2k?