SC400TT

iTrader: (4)

Actually guys, I am wondering if you know much about the TRAC system on the Lexus...Is it run from a separate module from the stock ECU? The SM4 does not do Traction control, the SM2 does, and I did not know this until tonight. So, if I can get the TRAC to still work without the stock ECU, then that would be optimal. Your input is most appreciated here.

Ryan

Steelwheel

Ryan, I'm not an expert in the trac system by any means but did some troubleshooting and understand some of the basics.

From what I see, the Main TPS (throttle pos. sensor) and Sub TPS position sensors are sent to the trac ecu and trac/abs ecu via the main ecm. The actual Sub TPS looks like it is controlled partially or fully by the Trac ECU. It appears that the Main ECM is necessary for the trac system to work properly. I can send you the diagram if you wish that I have. I would not bank on this diagram, but I bet it is pretty close.

lexhere27

There is a racing style traction control module in a group buy on Lextreme if you can't figure it out with the main ECU