M52 MS41 - System Overview
Siemens MS41 fitted to what would appear to be only the South African Defender this ECU can be more commonly found in various BMW cars. It is used in conjunction with a BMW 6 cylinder 2.8L petrol engine (the M52) which again only seems to have been for the South African market.
SM095 - M52 MS41 - System Help file
Version 1.22

M52 MS41 - Known Fitments
Vehicle makes, models and variants known or believed to be using this vehicle system, required diagnostic lead and degree of known compatibility.

Vehicle Make Vehicle Model Vehicle Variant Diagnostic Lead
Land Rover Defender South Africa 1997> Black OBD II Lead

M52 MS41 - Physical Details

SM095 - M52 MS41 - Diagnostic Capabilities (Read Fault Codes)
Reads the fault code memory. The ECU can self detect up to 36 different problems with itself, its wiring and its associated sensors, storing the respective code if it detects any malfunction or reading outside of pre defined acceptable limits. Not all stored faults may cause the fault warning lamp to illuminate.

SM095 - M52 MS41 - Diagnostic Capabilities (Clear Fault Codes)
This function diagnostically clears the fault code memory.

SM095 - M52 MS41 - Diagnostic Capabilities (Settings)
Values, configuration settings, and other stored information which can be read from the ECU. Read settings can also be stored as a standard HTML page for reference. These pages can then later be reloaded. Please note that some values may be read only due to the fact that they are supplied from the ECU's ROM or are internally calculated.
  • BMW Part Number: This is the part number for the ECU.
  • Hardware Number: This is the hardware version which denotes the processor and circuit board type.
  • Software Number: This denotes the coding inside the processor for the hardware.
  • Product Number: This is a number which defines the production number for the ECU
  • Coding Index: This is the coding identification for the programming maps.
  • Diagnostic Index: This is a number that indicates the diagnostic capabilities support level.
  • Bus Index: This is a number that indicates the bus communication support level, the vehicle communication buses.
  • Modification: This is a number that identify the variant of the ECU.
  • Week of Production: Gives the week in which the unit was built.
  • Year of Production: Gives the year in which the unit was built.
  • EMS Code: This number is the number which the MS41 ECU requires to be sent by the alarm to mobilize. This code will require programming into the 10AS alarm settings EDC/MS41 CODE box.

SM095 - M52 MS41 - Diagnostic Capabilities (Inputs)
Real time live display of the information the electronic control unit of the selected vehicle system is currently deriving from its input sensors.

  • Cyl 1-6 roughness: This value is related to the quality of the combustion in the engine. For a good combustion, the value should be between +3.5 and -2.5. Values between -2.5 and -7 indicates a possible problem with the mixture and/or ignition. Values between -7 and -12 shows that there is a problem with the mixture and/or ignition. The reading it is also influenced by the atmospheric pollution. In areas with high pollution, the reading might be out of range.
  • Engine speed: This is the speed of the engine measured in RPM, measured using the crankshaft sensor. Normal value for an engine fully warm under idle conditions is 850 RPM.
  • Vehicle speed: This is the vehicle speed measured by the speed transducer in the gearbox and this passed to the MS41 engine ECU via the instrument pack.
  • Air temperature (°C): This shows the current temperature of the air at the engine air intake measured by the air temperature sensor. Expected values are between 20 °C and 70 °C.
  • Coolant temperature (°C): This is the temperature of the coolant in (°C). The reading might be out of range if the engine is not fully warm and idle. The expected values for a fully warm engine over the full range of the throttle at idle are between 5 and 105 °C.
  • Air flow (Kg/h): This shows the consumption of air by the engine. Expected values for a fully warm engine at idle are between 9.5 kg/h and 17 kg/h.
  • Ignition angle (deg): This display shows the angle of the crankshaft when the mixture is ignited in the cylinder as measured by the crankshaft sensor. The expected values on a fully warm engine under idle conditions are between 5 deg and 15 deg.
  • Injector time (ms): This display shows the time the injectors are injecting fuel into the inlet manifold. The time indicates the efficiency of the engine. Expected values on a fully warm engine are around 4mS.
  • Cam position (deg): This shows the current position of the camshaft with respect to the current crankshaft angle. When the throttle is pressed, the cam position should change. Failure to do so, may indicate a fault with the VANOS. Expected values on a fully warm, idle engine is between 20 Deg and 40 Deg.
  • Idle control (%): The idle speed control gives an indication of the air in the mixture at idle. Values less than zero indicates too much air, due to air leakage past the butterfly in the throttle housing. Expected values are between -6% and +6%.
  • Idle setting (%): The idle setting shows the idle speed setting. Start the engine and allow it to reach a fully warm idle state as a number of readings may be out of range starting from cold.
  • Idle air adaption: This shows the adaption due to the air flow at idle. Expected values at idle are between -20 % and -50 %.
  • Engine status: this shows if the engine is cranking or not.
  • Enrichment: ON when extra fuel is applied to the mixture.
  • Battery voltage: This shows the vehicle battery voltage as measured directly by the MS41 engine ECU.
  • Fuel cut: This shows when fuel is cut off to the injectors.
  • Fuel pump: This shows if the fuel pump relay is ON or OFF.
  • VANOS: This displays the status of VANOS, ON or OFF. VANOS depends of the load on the engine.
  • Throttle pot (deg): This display shows the current angle of the throttle pedal. When the pedal is pressed, the values should change from 14 deg to 90 deg.
  • Throttle adaption (deg): This display shows the current adaption of the throttle. The adaption remains at a constant value until a fault occurs, after which the adapt ion changes accordingly. Expected values are between 5 deg and 23 deg.
  • Throttle load: This shows the current state of the throttle load on the engine, IDLE or LOAD (when the throttle is pressed to the floor) and NONE when the engine is stalled.
  • Throttle position voltage: This displays the current voltage of the throttle potentiometer. Expected values are between .5V and 3.8V.

SM095 - M52 MS41 - Diagnostic Capabilities (Other)
Choice of functions that can be performed:
  • Reset Adaption: This will reset the knock adaption, idle speed adaption, Throttle adaption, Mass airflow adaption, VANOS adaption. These values are adapted either by the ECU during normal driving or by a service adjustment. A reset operation is required after a repair or adjustment to any fuelling or idle speed control components. After the reset the idle speed and fuelling will change.
  • CO Adjustment: This will allow adjustments to be made to the CO emissions from the exhaust. The emissions from the exhaust should be monitored with the appropriate instrument. The adjustment can take place only if there are no fault codes stored and the coolant temperature above 85 °C
    1. Reduce CO: Press this button to reduce the CO.
    2. Increase CO: Press this button to increase the CO.
    3. Store Adjusted Value: When the CO setting is satisfactory store the CO setting by pressing this button.