Code 41....What am I missing?

[Hadmatt54]

Sorry, but I'm going to write a book here!!!
First off some background , my 1uz is from a 93 Crown Majesta UZS141, ECU that it had is 89661-30501, 40,40,40 pin.
My aim was always to wire this conversion as a early Crown UZS131, ECU's 89661-30430, 30431 or 30432 and that
is the route that I took. revamped the Throttle body to remove the traction butterfly and bits as per Gloverman's video
and during the wiring harness modifications VTA2 was tied to VC and IDL2 was connected to E2.
My truck is working great, overfueling some as my IAC rarely resets to Zero, but that is another post.
My OCD is getting the best of me and this light has to go!!!
Ever since my first start, I've had a check engine light with code 41. At first I thought it was only brought up when you
hit the throttle hard, but now that I have live data and can look at engine parameters in test mode, code 41 is always
there on start up and the throttle part was only event #2 that triggered the Check Engine light. Also without live data I
assumed that the nearly 23 year old TPS was toast, so I replaced it.
1987-1991 UZS131Crown TPS 89452-12050
1991-1995 UZS141 Crown Majesta TPS 89452-12050 and
89452-33010 * This is what my 1UZ had.
OEM Toyota replacement for both:- 89452-22090

So now to the testing part:
Initial setup was done with 0.010 feeler gauge and a test light, verified with a VOM as per Gloverman's video, and just for
the hell of it, I verified the measurements using the adjustment procedure that I found on this site and the measurements
were pretty much spot on.
IDL-E2 (Idle contacts closed)-0.006Vdc. (idle contacts open)-11.20Vdc key on, engine off, 12.25Vdc engine running.
VTA-E2 (Idle contacts closed)-0.473Vdc (idle contacts open)0.479-3.718Vdc (throttle fully open).
With live data and a VOM, these are measured values.
Throttle opening:-
0% - 0.479 Vdc
15 - 0.983
30 - 1.469
45
46.1 - 2.201
59.7 - 2.269
60
74.5 - 3.240
75
87.8 - 3.718

I verified these readings with 2 digital VOM(S) and I checked for needle deflection with an analog VOM and at no time was there any momentary interruption. Continuity tests, with the ECU plugs not connected, E2 at ECU to E2 at TPS and AFM
Continuity E2 to system ground or B- no continuity. (Once connectors are plugged in at ECU E2 via E1 has continuity with B-)
VTA1 not open, or shorted to ground or VC or IDL1. IDL1 not grounded or shorted.(So that rules out"open or short in TPS circuit
VTA1 for 0.5 sec. or more")
Have several ECU's , replaced existing with each spare test drove and recorded live data. In test mode Code 41 is present as soon
as engine starts with IDL contacts closed (so that rules out "IDL1 contact on and VTA1output exceeds1.5v for 0.5 sec or more")
The ECU that I had been running brought up code 24 (intake air temp) which is why I tested E2 circuit, but none of my spares did,
so I changed this out.

So after all this I'm wondering, Is it possible that there is enough difference between the out-put parameters of the new
OEM replacement TPS and the TPS that the ECU is expecting to be there to cause the ECU to trigger this code?







.

 

[gloverman]

I would try leaving VTA2 and IDL2 disconnected to see if it makes a difference.

 

[Hadmatt54]

Thanks Kelvin, I'll give that a try!

 

[Hadmatt54]

Removing IDL2 and VTA2 did the trick, code 41 is now gone!

However, since it is gone what I assumed to be background automatic transmission codes are now front and center. Now I have Codes 83, 84 and 85. These are communication codes where the engine ECU is trying to establish communication with the TCU on ESA1, ESA2 and ESA3 respectively.

Several years ago Nate was trying to troubleshoot these and a couple of other things on his , 1uz powered airplane and at the time Gloverman stated that he had never seen these. Also Samsdad was experimenting with hooking up a surf TCU to try to get rid of these. I never saw how either of these members fared in their endeavours.

So this week I tried some experimenting on my own. I have the proper early crown TCU that matches my ECU and wiring it in and establishing communication on those channels does not eliminate those codes and completely wiring this TCU into my Manual truck, when it isn't needed, seems to be a lesson in futility!

I'm hoping that some members may have found a solution, if not since I'm constantly looking at live data and the program has the capability of checking codes while monitoring data, I may just put in a switch on my Check engine light and turn it on when I need it. Not the best scenario, but I hate having a light on and so far I haven't found a satisfactory solution.