Determination Of The Fill Level; Determination Of Temperature - Mercedes-Benz OM 471 Introduction Into Service Manual

Function

Determination of the fill level

The sensor to determine the fill level functions according to the
float principle with magnetic transfer. A ring magnet fitted in the
float (7) actuates tiny reed contacts via its magnetic field through
the wall of the immersion tube (9). These reed contacts pick up an
uninterrupted measured voltage at a resistor data channel
(voltage divider principle), which is proportional to the height of
the fill level.
The values of the electrical resistance that changes along with the
position of the float (7) are transmitted in defined intervals as an
analog signal over the exhaust aftertreatment (ACM) control unit
(A60) to the engine management (MCM) control unit (A4). Using
the resistance value, this calculates the associated fill level.
i Introduction of engine OM 471 and exhaust aftertreatment > 09/2011 >
– This printout will not be recorded by the update service. Status: 09 / 2011 –
System components

Determination of temperature

The AdBlue surrounding the AdBlue" fill level sensor/temperature
sensor (B74) influences the inside of the measuring element
according to its temperature and therefore the size of the
electrical resistance.
The values of the electrical resistance that changes are
transmitted in defined intervals as an analog signal over the
exhaust aftertreatment (ACM) control unit (A60) to the engine
management (MCM) control unit (A4). Based on the resistance
value, the MR control unit calculates the associated temperature.
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