EAT ECU

When the ignition switch is turned to the 'ignition' position, current flows across the switch (C0099) to fuse 5, fuse 33, and fuse 35 of the passenger compartment fuse box (C0585) on a G wire. Fuse 5 (C0587) provides an ignition feed to the EAT ECU (C1835) on a GW wire. Fuse 33 (C0587) provides an ignition feed to the transfer box ECU (C1319) on a GP wire. Fuse 35 (C0587) provides an ignition feed to the Hill Descent Control (HDC) switch (C0365) on a GBY wire.

EAT ECU

The EAT ECU controls operation of the transmission via the following:

Electronic Pressure Regulator Solenoids (EPRS) The five EPRS located in the automatic transmission (C0244) are provided a Pulse Width Modulated (PWM) by the EAT ECU (C1835) on a P wire. The EAT ECU controls operation of the EPRS by providing earth paths on TB, R, B, K and YR wires.

NOTE: Wire colour TB is transparent with a black tracer.

Shift Control Solenoids

The three shift control solenoids located in the automatic transmission (C0244) are provided a feed by the EAT ECU (C1835) on a YU wire. The EAT ECU (C1835) energises the solenoids by providing earth paths on O, G, and Y wires.

Turbine Speed Sensor

The turbine speed sensor acts as an input speed sensor. The EAT ECU (C1835) provides a feed to the turbine speed sensor (C0244) on a U wire. The turbine speed sensor (C0244) returns an ac voltage pulse back to the EAT ECU (C1835) on an S wire. By measuring the peak to peak voltage of the voltage wave form, the EAT ECU can determine the speed of the turbine.

Output Shaft Speed Sensor

The EAT ECU (C1835) provides a feed to the output shaft speed sensor (C0244) on a W wire. The output shaft speed sensor (C0244) returns an ac voltage pulse back to the EAT ECU (C1835) on an N wire. By measuring the peak to peak voltage of the voltage wave form, the EAT ECU can determine the speed of the output shaft.

Transmission Temperature Sensor

The temperature of Automatic Transmission Fluid (ATF) is measured by the Negative Temperature Coefficient (NTC) transmission temperature sensor. The EAT ECU (C1835) provides a feed to the temperature sensor (C0244) on a BR wire. By measuring the voltage returned on a WR wire, the EAT ECU can determine ATF temperature.