Mercedes-Benz OM 471 Introduction Into Service Manual page 123

System components
A4 Engine management control unit
(MCM)
A57 NOx sensor control unit output for
exhaust aftertreatment unit
A57 b1 NOx sensor output for exhaust
aftertreatment unit
A58 SCR control unit
A60 Exhaust aftertreatment unit
(ACM) control unit
A67 AdBlue" metering device
A70 NOx sensor control unit input for
exhaust aftertreatment unit
The exhaust aftertreatment (ACM) control unit (A60) receives the
analog signals from the directly connected sensors. It receives the
NOx sensor signals over CAN connections and communicates with
the SCR control unit (A58) and the engine management (MCM)
control unit (A4).
AdBlue" injection
It uses the data supplied by the SCR control unit (A58) and the
engine management (MCM) control unit (A4) to calculate the
required AdBlue" quantity, which is then forwarded over the SCR
control unit (A58) to the AdBlue" metering device (A67).
Diesel particulate filter regeneration
The diesel particulate filter load status is monitored by the
temperature and pressure sensors. If active regeneration is
required, it is requested by the engine management (MCM)
control unit (A4).
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A70 b1 NOx sensor input for exhaust
aftertreatment unit
B37 Exhaust pressure sensor upstream
of diesel oxidation catalytic
converter
B38 Exhaust pressure sensor
downstream of diesel particulate
filter
B67 Exhaust temperature sensor
upstream of diesel oxidation
catalytic converter
B68 Exhaust temperature sensor
downstream of upper diesel
oxidation catalytic converter
B69 Exhaust temperature sensor
downstream of lower diesel
oxidation catalytic converter
– This printout will not be recorded by the update service. Status: 09 / 2011 –
W14.40>1597>79
B70 Exhaust temperature sensor
downstream of diesel particulate
filter
B73 Exhaust temperature sensor
downstream of SCR catalytic
converter
B74 AdBlue" fill level
sensor/temperature sensor
CAN 4 Drive train CAN
CAN 13 NOx>CAN
M25 SCR delivery pump