This article describes the scaling of the TPS output on the Modular Skyline plug-in ECUs.

The RB26DETT GTR Skylines, that is the R32 to the R34, had an electronic controller for the transfer case to select the amount of torque available for the front wheels. One of the sensors this module relies on is the throttle position, which is output as a variable voltage from the factory ECU.

The R33 GTST series 2 and later (so that’s the RB25DET) also had an electrically controlled limited slip differential, called the A-LSD, and so did the R34 GTT. Its controller also relies on the TPS output from the ECU. However the scaling or calibration is different between the different models.

The way this output is generated is with a PWM output on the ECU. This is converted into a 0-5V voltage using a circuit inside the ECU and output on the TPS output pin. This is also fed back into the TPS2 input, which means that you can monitor this voltage on the F11 window.



For this to work, the auxiliary output must be set to TPS output duty cycle, PWM at 1000 Hz. The only setting available then is found under functions -> TPS output. The type you can select is either R23-R34 GTR / R34 GTT, which is a 1:1 relationship between input voltage and output voltage, or R33 GTST in which case the output is 0.71 times the input voltage.



You can check that it’s working by watching the TPS2 voltage in the F11 window in relation to the TPS1 voltage as you move the accelerator pedal.


Thank you and happy learning!