Interface to Transmission Gearbox Control Unit (Z256)

High/Low Range Signal-pin 46 Diesel (pin 13 Petrol)
The High/Low signal is used by the Auto Gear Box Control Unit (Z255) to select the correct mode on application of the "MES" switch. Also, the gear shift points and strategies are very different in the different ranges.

Interface to "H-Gate"- pin 29 Diesel (pin 45 Petrol)
The "H"-Gate sensor module (Z254) displays selected gear information from the Gear Box Position Switch (X294), ratio information from the Transmission Gearbox Control Unit (Z256) and mode information from the gear box Auto Gear Box

Control Unit (Z255). The H-Gate receives an ignition 2 signal on the W wire. This is fed via fuse 6. It is grounded to the console ground E0808 via the B wire.

Information on the selected gear (PRNDL) is received from the Gear Box Position Switch (X294) on wires UB, UP UG. These three lines also go to the Auto Gear Box Control Unit (Z255) and the BeCM (Z238).

Information on the gear box mode (sport or manual) is received on the YG wire and the YR wire. These two lines also go to the BeCM (Z238).

The Transmission Gearbox Control Unit (Z256) high status is received on the NY wire. The low status is received on the NR wire. These two lines also go the Transmission Gearbox Control Unit (Z256) and the BeCM (2238).

The illumination signal is on the RU wire. The mode request is on the UO wire. This is sent from the H-gate Sensor Module (Z254) to the Auto Gear Box Control Unit (2255). The line is activated and deactivated by pressing the momentary action MODE button. The line is active at all times.