New or Modified Output Control Functions

NEW OR MODIFIED OUTPUT CONTROL FUNCTIONS

FUEL PUMP RELAY CONTROL







ME 7.2 controls the fuel pump relay as with previous systems with regard to engine speed input for continual activation of the relay.

When MRS III is incorporated into production vehicles (SOP 3-99) the ME 7.2 will also switch oft the fuel pump relay when an airbag is activated as an additional safety function.

E BOX FAN CONTROL







The E Box fan is controlled by ME 7.2. The control module contains an integral NTC temperature sensor for the purpose of monitoring the E box temperature and activating the fan.

When the temperature in the E-Box exceeds predetermined values, ME 7.2 provides a switched ground for the E Box fan to cool the E box located control modules.

With every engine start-up, ME 7.2 briefly activates the fan ensuring continued tan motor operation for the service life of the vehicle. This feature is intended to prevent fan motor "lock up" from lack of use due to pitting or corrosion over time.

SECONDARY AIR INJECTION

















The secondary air injection system is new to the 4.4 liter V8 engine. The system consists of the same components as previous systems with V8 specific locations.

The DME ME7.2 control unit controls the vacuum vent valve and the secondary air injection pump relay separately but simultaneously.

The secondary air pump operates at a start temperature of between 10 °C and 40 °C. It continues to operate for a max. of 2 minutes at idle speed.

ME 7.2 contributes an additional correction factor for secondary air "on" time with the additional input from the integral ambient barometric pressure sensor.

This sensor provides a base value to calculate the air mass being injected into the exhaust system. This helps to "tine tune" the secondary air injection "on" time, optimizing the necessary air flow into the exhaust system which reduces the time to catalytic converter light-off.

AUXILIARY FAN CONTROL












The Auxiliary Fan motor incorporates an output final stage that activates the tan motor at variable speeds.

The auxiliary fan is controlled by ML 7.2. The motor output stage receives power and ground and activates the motor based on a PWM signal (10 - 100 Hz) received from the ME 7.2.

Similar to the aux fan in the E46 with MS 42.0 control, the fan is activated based on the following factors:
- Radiator outlet temperature sensor input exceeds a preset temperature.
- IHKA signalling via the K and CAN bus based on calculated refrigerant pressures.
- Vehicle speed
- Battery voltage level

When the over temperature light in the instrument cluster is on (120 °C) the fan is run in the overrun function. This signal is provided to the DME via the CAN bus. When this occurs the fan is run at a frequency of 10 Hz.

ELECTRIC THROTTLE VALVE (EDK) CONTROL







The throttle valve assembly of the M62 TU is an electric throttle valve (EDK) controlled by an integral EML function of the ME 7.2. The throttle plate is positioned by a gear reduction DC motor drive.

Similar to the original Bosch EML 1.2 and 1.7 systems, the motor is controlled by proportionately switched high/low PWM signals providing precise plate positioning. The PWM signal is at a basic frequency of 2000 Hz.