FMI 8 – Abnormal frequency, pulse width or period
Fault code explanation: Faulty sensor / Faulty sensor circuit
Fault indication: DCU: Engine warning in DCU display.
CIU: Flash code
Electrical fault: 2.5
Value fault: None.
Symptom: The engine start time will increase, uses only crankshaft sensor.
Conditions for fault code: Incorrect sensor signal.
Possible reason: • Incorrectly mounted cam speed sensor.
• Electrical interference in the cam speed signal.
Suitable action: 1
Check wiring between cam spped sensor and EMS2.
2 Check the installation of the cam speed sensor.
3 Attempt to localize the source of interference.
4 Check and clean the cam speed sensor.
5 Check the contact pressure in socket 45 and 46 in engine connector A.
a Connector A
b Engine speed sensor, camshaft
sensor is an inductive sensor. The cam-
shaft sensor is used in the first instance to determine
the cylinder which is next in line for injection. A toothed
wheel installed on the camshaft is used to determine
the cylinder which is next in line for injection. The
toothed wheel has 7 teeth, one for each cylinder plus
an extra tooth for cylinder 1. When the camshaft with
toothed wheel rotates, impulses are generated in the
sensor. The impulses generated by in the sensor is
used by the engine control unit to determine the cyl-
inder which is next in line for injection.
Checking camshaft sensor wiring page 177
Checking camshaft sensor page 178
30-2 Fault Tracing
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