TRANSFER GEARBOX
B6
CIRCUIT OPERATION
2
Neutral Switch (X293) or Clutch Switch–
pin 34
A shift between ranges is possible when the
transmission is in neutral. The Transmission
Gearbox Control Unit (Z256) senses this via a
Park/Neutral Switch (X293) on automatic
transmission vehicles and via either a clutch switch
or a lever neutral switch on manual transmission
vehicles. This signal is passed via the BeCM (Z238).
Interface to “H– Gate”–
pin 35, 15 (automatic
transmission only)
The H–Gate gets the range information via a High
and Low status signal from the output of the
Transmission Gearbox Control Unit (Z256);
e.g. when the vehicle is in High then the High side of
the “H” is illuminated. When a range change to Low
is requested, the Low side of the “H” starts to flash
whilst the High side stays constant. When Low range
is obtained then the flashing light on the Low side
changes to constant and the High side light goes off.
If a range change is requested and not all of the
conditions are satisfied, then the current range will
stay illuminated and the desired range will flash and
continue flashing until all of the parameters are
satisfied or the request is removed.
If the gear lever is placed in the neutral position for
the gearbox and the transfer box then, after a five
second safety delay, the transfer box moves to
neutral and the lights on both side of the “H” are
extinguished.
Interface to Auto Gear Box Control Unit (Z255)
– pin 35
The High/Low signal to the Auto Gear Box Control
Unit (Z255) comes from the High range status lamp.
If the Auto Gear Box Control Unit (Z255) does not
receive the range information, then an incorrect gear
change mode could be selected, i.e. Manual rather
than Sport in High range and vice versa in Low
range. Also, the shift strategy is different between
the Economy modes of High and Low and so poor
shift quality could result.
Automatic Selector Park Interlock
When the gear selector lever is in the park position,
the shift interlock solenoid is deenergized and
prevents the selector from being moved to another
gear. To free the selector, the Ignition Switch (X134)
must be in position II and the brake pedal must be
depressed.
Current is then supplied to the solenoid through the
PR wire via fuse 13. The solenoid is grounded using
the B wire to the console ground E0808.
The solenoid is now energised, freeing the selector.
The solenoid is energised continuously whilst the
selector lever is in any position other than park and
the Ignition Switch (X134) is in position II.