Engine Management Status MED 9.2.1/MED 9.2.2 E65, E66 N73/N73TU
Engine Management Status MED 9.2.1/MED 9.2.2 E65, E66 N73/N73TU
Introduction
> N73
The MED 9.2.1 engine management system (engine electronics direct injection) is based on the ME 9.2 engine electronics.
The principal distinguishing features compared to the ME 9.2 (N62 engine) are:
- Enhanced computer capability (additional 1 MB flash)
- Modified oxygen sensor component that allows more detailed diagnosis in the oxygen sensors
- 1 DME control unit for each bank of cylinders
- Power is fed to the high-pressure injectors by a dedicated control unit for each bank of cylinders.
- Differentiated intake manifold actuation (N62) discontinued
- 3 knock sensors for each bank of cylinders
- Actuation of auxiliary air flaps in air cleaner housing
- Rail pressure sensor signal
- Flow control valve signal
> N73TU with introduction 09/06
The N73TU satisfies the legal emissions limits, e.g. Euro 4 standard for Europe or LEV II for the USA (LEV: Low Emission Vehicle).
The MED 9.2.2 engine management system is based on the ME 9.2.1 engine electronics
Measures on engine management:
- new processor
- additional software functions
- new oxygen sensors
- 2 control sensors upstream of catalytic converter (LSU 4.9)
- 2 monitor sensors downstream of catalytic converter (LSF 4.2)
- variable protocol for diagnosis-on CAN (D-CAN)
- modified integrated circuits
Brief description of components
The engine management consists of the following components:
Sensors
- Accelerator pedal module
- 2 hot-film air mass meter
- Knock sensor 1 (cylinders 1-2)
- Knock sensor 2 (cylinders 3-4)
- Knock sensor 3 (cylinders 5-6)
- Knock sensor 4 (cylinders 7-8)
- Knock sensor 5 (cylinders 9-10)
- Knock sensor 6 (cylinders 11-12)
- Crankshaft sensor
- Oxygen sensor in front of catalytic converter
- Oxygen sensor behind catalytic converter
- Oxygen sensor before catalytic converter 2
- Oxygen sensor after catalytic converter 2
- Temperature sensor at coolant outlet (radiator)
- Coolant temperature sensor
- Inlet camshaft sensor
- Exhaust camshaft sensor
- Inlet camshaft sensor 2
- Exhaust camshaft sensor 2
- 2 Valvetronic eccentric shaft sensors
- 2 pressure sensors in the intake manifold
- Oil condition sensor
- Ambient pressure sensor in the DME control unit
- 2 rail pressure sensors
Switches
- Brake light switch
- Engine oil pressure switch
Control units
- DME = Master
The DME (master) control unit actuates the engine cylinder bank 1-6.
- DME2 = Slave
The DME2 (slave) control unit actuates the engine cylinder bank 7-12.
- VTC (Valvetronic) control unit
2 VTC control units are integrated in the housing of the VTC control unit.
- 2 HDEV (high-pressure injectors) control unit
The 2 HDEV control units actuate the high-pressure injectors.
[For further information, please refer to SI Technology (SBT) 13 01 03 023] Direct Injection E65, E66 N73/N73TU
Actuators
- 2 electric throttle-valve actuators
- Solenoid valve for auxiliary air flaps
- High-pressure injectors 1-12
- Electric fan
- E-box fan
- Secondary air pump
- Fuel evaporation control valve
- VANOS solenoid valve, inlet camshaft
- VANOS solenoid valve, exhaust camshaft
- VANOS solenoid valve, inlet camshaft 2
- VANOS solenoid valve, exhaust camshaft 2
- Ignition coil for spark plugs 1-12
- Mapped thermostat
- Return cut-off valve
- Flow control valve
- Pressure damping vent valve
- Auxiliary air flap
- Exhaust flap
Relays
- DME main relay
- Starter relay
- Secondary air pump relay
- 2 relays for Valvetronic motor
- Relay for power supply to ignition coils 1-12
System functions
One DME control unit is used for each bank of cylinders. Both control units are identical in design and have the same programming status. The two control units are classified as master and slave control unit by a selector pin.
The master control unit (cylinder bank 1-6) receives the input signals from the following sensors/switches:
- Accelerator pedal module
- Oil condition sensor
- Alternator
- Coolant temperature
- Engine oil pressure switch
- Coolant temperature, radiator outlet
- Brake light switch
The master control unit forwards these input signals to the slave control unit via the local CAN.
All other input signals are transmitted directly to the control unit assigned to the respective cylinder bank.
Output signals that are not specific to one cylinder bank (e.g. electric fuel pump or exhaust flap) are transmitted to the relevant actuators by the master control unit.
The signal from the crankshaft sensor is transmitted simultaneously to both control units.
Notes for service staff
Service staff should note the following points:
- General information: ---
- Diagnosis: ---
- Encoding/programming:
Subject to change.