Low Line Audio Head Unit
LOW LINE AUDIO HEAD UNIT
The low line Head Unit (HU) contains the following functionality:
^ Radio tuner
^ Single disc CD player
^ Amplifier
The HU communicates with other vehicle systems on the CAN bus.
Connector C1354 Pinout Table For Low Line Head Unit
Connector C1354 Pinout Table For Low Line Head Unit:
The HU incorporates a power management function. Should the vehicle battery level drop below a predetermined level the unit will limit its functionality. The HU receives CAN signals which help it determine the wake up/shut down process. The following describes the wake up / shut down triggers initiated by the ignition key switching cycle.
^ If CAN Bus activity is detected and the battery voltage is above 12.3 volts, the HU will display the clock on the LCD.
^ With the ignition key inserted and the ignition switch turned to ACC/AUX, the HU will operate normally in power save mode if the HU was powered down with the 1 hour power save time out.
^ If the key is moved from ACC/AUX to IGN/RUN the HU still has normal functionality.
^ If the key is moved from IGN/RUN to crank HU audio is muted during engine crank.
^ Once engine cranking is complete and the ignition key is returned to IGN/RUN the HU will operate in normal power mode.
^ Turning the key from IGN/RUN to ACC/AUX will cause the HU to go into power save mode, limiting the output volume.
^ Turning the key from ACC/AUX to the key in position will cause the HU to operate in power save mode for ten minutes. After this time the HU will go into stand by mode. If the ignition key is not removed and the CAN network goes into sleep mode, the HU will shut down completely. The HU will only power up again once any the following conditions have been met; The door lock status changes from lock to unlock, the key position changes from key in to ACC/AUX, pressing the power button on the HU, inserting or ejecting a CD.
^ Removing the ignition key will cause the HU to enter stand-by mode. The only exception to this is if a phone call is in progress, where the HU will stay powered until the phone call is over and then return to stand-by mode.
All of the previous power strategies rely upon receiving the ignition key switch status via CAN.
Transit Mode
Transit mode is used to reduce the vehicle battery current drain whilst the vehicle is being stored or transported. Transit mode is entered/exited via a CAN signal from T4. In transit mode the following circuits will be disabled:
^ AUX and phone call
^ AUX and phone call
^ Clock
^ Antenna power
^ LED illumination
In transit mode the CAN port and the ON/OFF switch are the only circuits that are left active.
The CAN port is left open to allow the EXIT from transit mode signal to be received. The ON/OF switch is left active to allow feedback to the driver via the HU LCD, that the unit is in Transit mode should the driver attempt to power up the HU. This will only occur when the vehicle engine is running and the battery is above 12.3 Volts.
Radio Function
The radio tuner is located in the head unit. The radio is capable of receiving AM and FM waveband and can store 18 FM pre-sets and 12 AM pre-sets. The AM presets are stored as follows:
European AM Preset Storage
^ 6 MW
^ 6 MWa
^ 6 LW
^ 6LWa
NAS AM Preset Storage
^ 6 MW1
^ 6 MW2
^ 6 MWa
CD Function
The HU includes single play CD player. The CD player has all the usual functions of a CD player:
^ CD play
^ Previous/ next track
^ Shuffle tracks
^ Load/eject CD
^ Scan
^ Repeat