DESCRIPTION AND OPERATION
4.42 RANGE ROVER
Transmission Temperature Sensor
The temperature of the 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.
Inhibitor Switch
The inhibitor switch is mounted on the LH side of the transmission, and enables the EAT
ECU to monitor the position of the manual selector spool valve and the selected drive
program. The EAT ECU (C1835) provides an ignition feed to the inhibitor switch (C0244) on
a YB wire. When Park or Neutral is selected, the inhibitor switch (C0244) returns a feed back
to the EAT ECU (C1835) on an O wire. When Drive is selected, the inhibitor switch (C0244)
returns a feed back to the EAT ECU (C1835) on a B wire.
When shift solenoid A is energised, the inhibitor switch (C0244) returns a feed back to the
EAT ECU (C1835) on a PW wire. When shift solenoid B is energised, the inhibitor switch
(C0244) returns a feed back to the EAT ECU (C1835) on a YB wire. When shift solenoid C
is energised, the inhibitor switch (C0244) returns a feed back to the EAT ECU (C1835) on a
TB wire.
NOTE: Wire colour TB is transparent with a black tracer.
Shift Interlock Solenoid
To lock the selector lever assembly, the EAT ECU (C0193) provides a feed to the shift
interlock solenoid (C0673) on a BP wire. An earth path is provided by the EAT ECU (C0193)
on an NP wire.
Steptronic
When manual (Steptronic) mode is selected, the EAT ECU selects gears according to inputs
received from the Steptronic switch. The EAT ECU (C0193) provides two feeds to the
Steptronic switch (C1664); one on a UY wire, one on a US wire. If a downshift is requested
via the selector lever, a momentary earth is created. Current on the UY wire is allowed to
flow across the switch to earth on an NB wire. Sensing this, the EAT ECU downshifts 1 gear.
If an upshift is requested via the selector lever, a momentary earth is created. Current on the
US wire is now allowed to flow across the switch to earth on an NB wire. Sensing this, the
EAT ECU upshifts 1 gear.
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