[SOLVED] Turn-Assist/MTS troubleshooting (1 Viewer)

[nwfl4runner]

EDIT: solution here


-----------------------------------------------------------------------------------------------------------------------------------------------------------






I am working on trying to add MTS/Turn-Assist (OTA) to my 2010 LX. I've swapped the skid-control ECU/master cylinder, switch panel, and combination meter (gauge). No error codes/DTC, zero-point calibration all done. I had to repin the skid-control ECU, and run 2 new wires to the switch panel.

I now how 5 speed crawl. When I'm in 4LO and hit crawl, the menu appears, and I can scroll through it. I can do the active data test in techtstream and the CRAWL icon will appear. The problem I have is that neither MTS nor OTA appear. When I switch to 4LO the MTS menu doesn't appear, and when I'm in crawl, the OTA doesn't activate when you hit the button. The icons can be triggered on the dash through techstream, and I know the switch works (bench test).

What I am confused about is that the skid-control communicates the MTS and Turn-Assist to the combination meter/gauge cluster through CAN, just like with CRAWL. I am trying to get smart about CAN, but why would it work perfectly for CRAWL and not MTS/OTA?

I did measure the voltage on the OTA pin. With IG on it should read between 11-14V, and mine reads between 9.9-10.2V. TIS says low voltage means replace the skid-control ECU/master cylinder. I'm worried that the one I got off a wrecked 2013 is in fact shot.

On the off chance that the 4wd ECU plays a roll in MTS, I swapped in a 2013 ($190 and I was already half way across this crap river). No change.

Just wanted to see if anyone had any thoughts of what I should be checking. I just can't believe that the 2 new functions I am adding would be the only things not to work if the skid ECU is communicating via CAN and the other outputs on CAN are working.

So... help??? At least I got to deep clean my console...

 

[afgman786]

Might not be help, but questions to add. Are the ECUs that you replaced all that is needed to get Turn assist to work and MTS? I haven't looked into it, but I would've figured turn assist would require more than just that, maybe firmware updates or something if its not mechanical changes.

 

[nwfl4runner]

Might not be help, but questions to add. Are the ECUs that you replaced all that is needed to get Turn assist to work and MTS? I haven't looked into it, but I would've figured turn assist would require more than just that, maybe firmware updates or something if its not mechanical changes.

So the wiring for the OTA goes directly from the control panel switch to terminal 29 on the Skid-Control ECU. It passes through 2 connectors, but no junction blocks, so just direct connect.

I've attached a bunch of the files below:

Looking at the CM-terminals (Combination Meter Terminals), I am wondering if reading on line A that leads to the ECM means I need to replace that as well?

"Combination Meter" shows that OTA/MTS should activate on the combination meter via CAN from the Skid-control ECU

"MTS Troubleshoot" shows checking CAN for errors, as does "OTA-troubleshoot"

"Skid-ecu wiring" shows the 2013 pin out

 

[nwfl4runner]

And here is the skid ECU system diagram and description as well

 

[nwfl4runner]

Well in for a penny, in for a pound. Ordered an OEM master cylinder and will swap it out for the wrecker yard one. Unfortunately Toyota doesn't sell the gasket between the ECU and the hydraulics, so I'll disassemble the current ECU after swapping in one I know is good.

 

[Acrad]

Cool & Interesting mod. On the 10-19 460s... MTS logic is contained in the Driving Support Switch Control and so a simple ECU swap makes it plug-and-play enable for MTS.

If you don't swap that ECU on the 460 you just have Crawl without MTS after doing a ZPC.

ZPC not needed if just adding MTS.

I've never looked at FSM data on how the LC/LX handles it. 2020+ 460 MTS/CC logic appears to have moved to the skid control ECU

mods:body [GX Offroad]

lexusgxor.com

 

[highfructose]

I am working on trying to add MTS/Turn-Assist (OTA) to my 2010 LX. I've swapped the skid-control ECU/master cylinder, switch panel, and combination meter (gauge). No error codes/DTC, zero-point calibration all done. I had to repin the skid-control ECU, and run 2 new wires to the switch panel.

I now how 5 speed crawl. When I'm in 4LO and hit crawl, the menu appears, and I can scroll through it. I can do the active data test in techtstream and the CRAWL icon will appear. The problem I have is that neither MTS nor OTA appear. When I switch to 4LO the MTS menu doesn't appear, and when I'm in crawl, the OTA doesn't activate when you hit the button. The icons can be triggered on the dash through techstream, and I know the switch works (bench test).

What I am confused about is that the skid-control communicates the MTS and Turn-Assist to the combination meter/gauge cluster through CAN, just like with CRAWL. I am trying to get smart about CAN, but why would it work perfectly for CRAWL and not MTS/OTA?

I did measure the voltage on the OTA pin. With IG on it should read between 11-14V, and mine reads between 9.9-10.2V. TIS says low voltage means replace the skid-control ECU/master cylinder. I'm worried that the one I got off a wrecked 2013 is in fact shot.

On the off chance that the 4wd ECU plays a roll in MTS, I swapped in a 2013 ($190 and I was already half way across this crap river). No change.

Just wanted to see if anyone had any thoughts of what I should be checking. I just can't believe that the 2 new functions I am adding would be the only things not to work if the skid ECU is communicating via CAN and the other outputs on CAN are working.

So... help??? At least I got to deep clean my console...

Having that turn assist feature and a selectable “aggression” of the atrac system would be a nice addition.

 

[nwfl4runner]

Well it’s going to be a bear to figure this out. New OEM skid control ECU results in same issue - turn assist and MTS do not work. Good news is I now have 2 spare master cylinders so I’ll be well prepared 10 years from now.

I did notice that on start up neither the MTS or OTA lights appear in the dash, but they should illuminate for 3 seconds along with the other start up lights. I think there must be a CAN issue I am missing as everything appears in techstream and can be activated, but when in 4LO it all stops, but with no DTCs

search continues....

 

[Acrad]

Wonder if there is something in BCM?

Does the LX use a separate 4WD Control ECU like the 460?

 

[nwfl4runner]

There is a separate 4wd ECU and I swapped that already - it’s odd that the skid control ECU should supply the correct info to the combination meter and DOES for the new 5 speed crawl but doesn’t for the others. Interference?

 

[grinchy]

did the new ecu have the correct voltage?

 

[Acrad]

I'm still wondering if there is some logic in other system management modules that is preventing this from working. On the 460 existing functions were being brought out... here functionality is being introduced that wasn't present on existing model at the time.

Are BCM and ECM revs different between 13-15 + and previous years?

Was Trailer Sway control new for '13 as well?

 

[highfructose]

does anyone know precisely what turn assist does?

does it just pulsate one particular brake to “hold” one of the rear wheels mostly stationary...from which the rest of the vehicle “pivots” and turns?

 

[nwfl4runner]

I'm still wondering if there is some logic in other system management modules that is preventing this from working. On the 460 existing functions were being brought out... here functionality is being introduced that wasn't present on existing model at the time.

Are BCM and ECM revs different between 13-15 + and previous years?

Was Trailer Sway control new for '13 as well?

I know the BCM/ECM are different. My naive thought was that they wouldn't play a role once the skid ECU was on CAN, but admittedly I'm in over my head lol.

@highfructose - I think turn-assist applies more pressure to the inner rear brake when turning.

 

[highfructose]

I know the BCM/ECM are different. My naive thought was that they wouldn't play a role once the skid ECU was on CAN, but admittedly I'm in over my head lol.

@highfructose - I think turn-assist applies more pressure to the inner rear brake when turning.

Think it’s possible/reasonable to do a manual programming to pulsate a particular rear brake without wreaking havoc on the rest of the system? I would manually pulsate a button to do that during a tight turn offroad if I could.

 

[nwfl4runner]

did the new ecu have the correct voltage?

Voltage was a bit higher, 12+ with car on - I figure with a brand new skid ECU the voltage is what the voltage will be lol

 

[Acrad]

I am kinda getting the feeling that these '13+ changes on LC/LX are similar to what was done with 20+ GX... that nut still hasn't been cracked with a confirmed retrofit for crawl/MTS(covered in other thread). ECU was eliminated and placed into the skid control ECU but not sure if the firmware even has the logic to do crawl/MTS.

Even then... .could be upstream ECU compatibility issues or commands that aren't even there on the CANBUS.

Obviously turn assist isn't a function on the 460 but can relate to the challenge.

Just hoping you get some extra eyes on this. It usually helps when others who have the same vehicle and also attempting mod can chime in as well. I'm basically an observer though... don't have a LC/570 and/or any significant documentation.

You may want to link to this thread on other platforms back to this one... the more eyes on this the better.

 

[nwfl4runner]

Yeah, I am trying to figure out where I'm screwing up, as the wiring diagram doesn't give me more insight. I get the feeling that the icons not appearing during the IG-ON process means there is another module involved, but for the life of me I don't know what. Ran through the Skid ECU test mode to activate the switch, and it shows that being completed. This would suggest to me that I do have to begin checking other CAN systems. Ugh.

 

[nwfl4runner]

SOLVED!!!!! MTS/5-speed crawl/OTA retrofitted into a 2010! All working as intended. Full write-up coming... but for now there is joy!

 

[Acrad]

Cool!!! Very good to hear