FMI 5 – Current below normal or open circuit
Fault code explanation: Faulty sensor / Faulty sensor circuit
Fault indication: DCU: Engine warning in DCU display.
CIU: Flash code
Electrical fault: 3.4
Value fault: 3.5
Symptom: Engine smokes more than normally during acceleration or load increase.
Conditions for fault code: The voltage on pin A22 on the EMS2 is less than 0.07 Volt.
Possible reason: • Open circuit in air inlet pressure signal cable.
• Open circuit in 5V supply cable to sensor.
Short circuited air inlet pressure signal cable to sensor negative cable.
• Faulty sensor.
Suitable action: 1 Check the cable harness between the air inlet pressure sensor and
2 Check the contact pressure in socket 7 and 22 in engine connector A.
3 Check the sensor.
The sensor is an active sensor, i.e. the sensor must
voltage. The air inlet pessure sensor
measures the absolute pressure, which is the sum of
the air inlet pressure and atmospheric pressure (300
kPa thus corresponds to a boost pressure of 200 kPa
when atmospheric pressure is 100 kPa).
Pin 7 on the engine control unit (EMS2) connector A
provides pin 3 on the sensor with an operating voltage
of +5 Volt. Pin 1 on the sensor is connected to battery
negative via pin 11 on the EMS2. The output signal
from the pressure sensor, pin 4 on the sensor to pin 22
on the EMS2, is a voltage signal that is proportional to
the air inlet pressure. The output signal is linear within
the sensors working range.
a Connector A
b Intake manifold temperature
30-2 Fault Tracing
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