Operating Modes

Description

Operating Modes
The instrument pack will function in seven modes:
^ Shut down
^ Normal
^ Powered/Unpowered
^ Diagnostic
^ Crank
^ Standby normal
^ Low battery voltage.

Shut Down Mode
The instrument pack enters shut down mode when the ignition is moved from position II to the off position (O). Ignition voltage is removed and only the permanent battery feed is available. All CAN gateway, diagnostic, instrument pack and warning lamp functions are suspended. Some conventionally wired warning lamps can still function in shut down mode, i.e.; hazard warning lamp.

When the instrument pack senses that the ignition supply has been removed, it can remain in normal mode for up to fifteen seconds to allow the microprocessor to power down. In shut down mode the total current draw for the instrument pack does not exceed 1 mA.

Normal Mode
The instrument pack enters normal mode when battery voltage from ignition switch position II is received. The ECM transmits a message for the CAN standard. If this message is correct or not received, the instrument pack remains in normal mode. If an incorrect CAN standard message is received, the instrument pack will enter standby normal mode.

Powered/Unpowered Modes
Powered mode is the standard operational condition for the instrument pack. In this condition the pack receives a permanent 12V battery supply, no ignition supply or CAN messages. The microprocessor is also off but the real time clock will remain powered.

Unpowered mode is entered when the vehicle battery is disconnected. When the power supply is restored, the pack will resume powered mode.

Diagnostic Mode
To enter diagnostic mode, the instrument pack must first be in normal or standby normal mode and T4 or another diagnostic tool must be connected to the diagnostic socket. The instrument pack will enter diagnostic mode when it receives a valid message on the ISO 9141 K Line. Confirmation of access to this mode is given by a 'dIAg' message in the LCD.

Diagnostic mode is exited by receipt of a message from the diagnostic tool to terminate diagnostics. Removal of the ignition switch position II battery supply or disconnection of the diagnostic communication to the socket will also terminate the diagnostic mode.

Crank Mode
When the starter motor is cranking the engine, the current drain may cause the values of inputs and CAN messages to become corrupted or invalid. The instrument pack senses that cranking is operative when ignition switch positions II and III are active and the ignition feed from switch position II falls to approximately 3V.

During cranking, all inputs to gauges are suspended and the gauges will remain in their pre-crank state. The odometer display is not affected.

Standby Normal Mode
Standby normal mode is used if an incorrect CAN standard message is received and also allows access to diagnostics. In this mode all CAN transmissions are terminated and the pack will not respond to any CAN messages received. All conventionally wired warning lamps will function normally and the pack can enter diagnostic mode if required. A fault flag is recorded in the EEPROM for the CAN standard message fault.

Low Battery Operation
If the permanent battery supply voltage falls to below 8V, CAN message transmissions will be suspended and received CAN messages will be ignored, analogue gauges will read zero and warning lamp operation is suspended. When the voltage rises above 8V, normal instrument pack operation is resumed.