Radio Circuit Operation

Radio Power 

The radio is supplied power by a fused B+ circuit. The radio does not use a discrete ignition feed circuit for power moding. The power mode master provides the system power mode to the radio via serial data messages. The power mode master determines the system power mode by processing power mode information from ignition switch inputs. Serial data power modes supported by the radio are OFF, ACCESSORY, RUN, and CRANK REQUEST.

If the radio is turned off during an active ignition cycle, then the ignition is cycled OFF and the radio is allowed to go into a sleep cycle, upon the next ignition cycle the radio will revert to an ON state. This is considered a normal characteristic of this radio.

The radio can be turned ON with the ignition OFF. After 10 minutes of inactivity the radio will power down. If any setting (e.g. changing the station) or volume has been changed or if the radio has been powered OFF than back ON the 10 minute timer will reset from that point.

The radio can stay on after RAP has timed out if an OTA update is pending.

Radio Retained Accessory Power 

The radio retained accessory power system is controlled by serial data. The activation/termination is the same as relay operation (see Retained Accessory Power Description and Operation) with a few exceptions; the only door switch that will turn off the radio during retained accessory power is the driver door open switch. If the supplier of the radio is Denso Ten America Limited the power/mute button will not function in RAP mode, all other functions of the radio will operate normally. This is a normal characteristic of this radio. To get the power/mute button functional disable RAP mode by opening and closing the drivers door.

Radio Grounds 

The vehicle harness provides a ground for the radio circuits. The radio may also be case grounded.

Radio Data Link Communication 

The radio communicates with other modules via serial data.

Radio Audio Outputs 

Each of the audio output channel circuits (+) and (-), at the radio have a DC bias voltage that is approximately one half of battery voltage. The audio being played on the system is produced by a varying AC voltage that is centered around the DC bias voltage on the same circuit. The AC voltage is what causes the speaker cone to move and produce sound. The frequency (Hz) of the AC voltage signal is directly related to the frequency of the input (audio source playing) to the audio system. Both the DC bias voltage and the AC voltage signals are needed for the audio system to properly produce sound.