DESCRIPTION AND OPERATION Instrument Pack The instrument pack (C0230) acts as a gateway, relaying CAN messages to and from different components throughout the vehicle as follows: Pressure Sensor The pressure sensor is located in the high pressure A/C line adjacent the compressor, and replaces the more traditional trinary pressure switch. The instrument pack (C0230) provides a 5 V reference voltage to the pressure sensor (C1257) on a UO wire. The pressure sensor (C1257) is provided an earth path via the instrument pack (C0230) on a PB wire. The pressure sensor (C1257) provides the instrument pack (C0230) a signal feed on a UG wire. The value of this signal feed is dependent upon the pressure within the A/C system. The instrument pack relays this information to the ECM via the CAN BUS. The ECM uses this to determine the pressure within the A/C system, enabling it to carry out the following tasks: l To provide a safety cut-out function if the pressure within the A/C system goes either too high or too low. l To control the speed of the cooling and condenser fans via the cooling fan control unit. l To help control engine idle speed. Evaporator Temperature Sensor The evaporator temperature sensor is used to ensure the evaporator doesn't freeze. The instrument pack (C0230) provides a feed to the evaporator temperature sensor (C0417) on a GO wire. The sensor (C0417) is earthed on a B wire. The instrument pack relays evaporator temperature sensor status to the ECM via the CAN BUS. NOTE: The ECM also uses the evaporator temperature sensor signal in conjunction with the pressure sensor signal to help control engine idle speed.
4.94
FREELANDER 02MY
