Mercedes-Benz OM 471 Introduction Into Service Manual page 144

GF49.20>W>3007H
ENGINES 471.9 in MODEL 963, 964 with CODE (M5Z) Engine version Euro VI
Location
1 Exhaust aftertreatment unit:
B73 Exhaust temperature sensor
downstream of SCR catalytic
converter
Task
The exhaust aftertreatment control unit
(ACM) (A60) records the temperature of the
exhaust flow in the chamber downstream
of the SCR catalytic converter via the
exhaust temperature sensor downstream of
the SCR catalytic converter (B73).
Design
The sensor consists of a stainless steel housing. The housing
contains a measuring element, a PTC resistor.PTC stands for
"Positive Temperature Coefficient" and means that the electrical
resistance increases as the temperature increases.
i Introduction of engine OM 471 and exhaust aftertreatment > 09/2011 >
Exhaust temperature sensor downstream of SCR catalytic converter, component
description
– This printout will not be recorded by the update service. Status: 09 / 2011 –
System components
Function
Depending on its temperature, the gas flowing past the probe
influences the measuring element inside, and makes its electrical
resistance change.
Since the sensor has a constant measuring current flowing
through it, the resistance change causes a voltage drop, via which
the exhaust aftertreatment control unit (ACM) (A60) can work out
the associated temperature value.
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