Mercedes-Benz OM 471 Introduction Into Service Manual page 141

System components
GF49.20>W>3006H
ENGINES 471.9 in MODEL 963, 964 with CODE (M5Z) Engine version Euro VI
Location
1 Exhaust aftertreatment unit:
B70 Exhaust temperature sensor
downstream of diesel particulate
filter
Task
The exhaust aftertreatment control unit
(ACM) (A60) records the temperature of the
exhaust flow downstream in the deflection
chamber downstream of the diesel
particulate filter (DPF) via the exhaust
temperature sensor downstream of the
diesel particulate filter (B70).
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.
138
Exhaust temperature sensor downstream of diesel particulate filter, component
description
– This printout will not be recorded by the update service. Status: 09 / 2011 –
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.
20.7.11
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