The crankshaft sender is an active sender which operates on the Hall sender principle. An evaluable signal is transmitted by the sensors from about 20 rpm. The sender is supplied with a constant voltage of 5 V from the DME control unit.
This engine concept utilizes a stereo Lambda control. The Lambda probes (resistance difference probes) are located in the exaust manifold. This location allows the dead times for the individual exhaust paths to be reduced and more precisely monitored. Each probe monitors three cylinders (cylinders 1-3 and 4-6). Test example: If the injector opening time of the first line of cylinders (cylinders 1-3) is changed, a reaction should be observed on the Lambda probe of the first line. If this is not the case, renew the probes.
The MS 41 has a double temperature sensor for the DME control unit and the remote thermometer in the instrument cluster. The temperature sensor converts the temperature of the engine coolant into an electrical value (resistance). This is done using an NTC. A coded connector makes it impossible to attach the incorrect connector at the wiring harness.
The knock sensors detect a knocking combustion and work in accordance with the familiar operating principle of the Pizzero sensor. One knock sensor monitors cylinders 1-3, another monitors cylinders 4-6. They are only linked at the connector, or at the wiring harness, and transmit separate signals to the DME control unit.
Thanks to a modified physical construction, the ignition coils have been made smaller and lighter (300g instead of 400g). The MS41 and MS40 ignition coils cannot be interchanged.
The control unit is a single plate unit with an 88-pin connector. There is only one control unit version for each engine displacement. The difference between manual and automatic transmission, or between catalyst and catalyst preparation is learned by the control unit. The learned version can be reset using DIS or MoDiC ("Diagnosis" "Service Functions" "Delete Adaptions")
The control unit has a permanent data memory (EEPROM). Here, the adaptions and contents of the fault memory are stored in a non-volatile form. These entries can only be deleted using DIS / MoDiC. They are not deleted by disconnecting the battery. The adaptions must be deleted if the control unit from another vehicle is installed (test exchange).