Group 30: Electrical system
Diagnostic Trouble Codes
79
Circuit description
The sensor is an active sensor, i.e. the sensor must
receive operating voltage. Pin A7 on the engine control
unit (EMS 2) provides pin 3 on the sensor with an op-
erating voltage of +5 Volt. Pin 1 on the sensor is con-
nected to battery negative via pin A11 on the EMS 2.
The output signal from the pressure sensor, pin 2 on
the sensor to pin A19 on the EMS 2, is a voltage sig-
nal that is proportional to the rail pressure.
Fault tracing
FMI 0 Rail pressure is too high
Conditions for fault code:
Rail pressure depends on engine revolution and en-
gine load.
Possible reason:
•
Faulty MROP.
•
Faulty rail pressure sensor.
Suitable action:
1.
Check MPROP cables and connectors.
2.
Check function of rail pressure sensor.
FMI 2
Conditions for fault code:
Plausibility fault.
Possible reason:
•
Faulty rail pressure sensor.
Suitable reason:
1.
Check function of rail pressure sensor.
rail pressure
engine
interface
Note! Only TAD 650, 660, 750, 760 has an engine interface. On
TAD 734 the wiring to the EMS 2 is the same but without any en-
gine interface.
