300SE (140.032) L6-3.2L (104.990) (1992)
Module Box
LOCATION AND I.D.
The control unit (N3/1) is located in the module box in engine compartment, passenger side firewall. The control unit connector is color coded
dark green/light green.
Injection Control
OPERATION
The ECU contains several programs and functions which are briefly described below.
The ECU uses the following information:
^ Voltage supply (+)
^ Starter circuit
^ Engine temperature from coolant temperature sensor (B11/2)
^ Intake air temperature from intake manifold temperature sensor (B17/7)
^ Intake air mass from air mass sensor (B2/2)
^ Various information from the controller area network (CAN)
^ ABS/ASR information from ABS/ASR control unit (N30/1)
^ Air/fuel mixture from oxygen sensor (G3/2)
CONTROL FUNCTIONS
Injection Base Quantity (Normal Driving) Function
During normal driving, the ECU uses the input devices to regulate injection frequency and timing. The two most influencing components are:
^
Air mass sensor with hot-wire (B2/2)
^
Engine RPM signal (TN)
Start And Warm-up Function
The start control provides for longer injection duration to enrich the mixture. The final air/fuel mixture is dependent on the engine coolant
temperature. Mixture enrichment stops when the engine is at operating temperature.
Full Load And Acceleration Function
During full load or acceleration, a richer air/fuel mixture is provided to achieve maximum engine power. This will also keep combustion heat and
catalytic converter temperature at an acceptable level.
Deceleration Shut-off Chart
Deceleration Shut-off Function
During deceleration, some or all fuel injectors are turned off (in all gears) if engine temperature is above 70 °C (158 °F). The engine speeds for
injection cut-off/ restart are shown in the chart.