Operation0515−1/A1
Winterthur Gas & Diesel Ltd.
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2. Defective Fuel Pump Actuator
2.1 Fault Identification
If an actuator becomes defective, its output stays the same or changes slowly to zero
supply. The toothed rack does not change when the load changes.
A failure message shows in the ECS (see 4002−2, paragraph 3.15 Log Messages).
The fuel pumps stay in their last position when no control signal is received.
At high engine load, the remaining serviceable fuel pump actuators control the fuel
quantity.
At low engine load, the pressure control valve (PCV) 10-5562_E0_5 controls the fuel
pressure control function.
Note: The fuel quantity released from the pressure control valve flows into the
fuel return.
Operation with these control functions must be prevented if possible, or kept for only a
short time (see 5562−1 Pressure Control Valve).
If there is an overpressure in the HP fuel system (i.e. the PCV becomes defective),
the pressure relief valve (which is part of the PCV) opens and the level switch
LS3426A activates an alarm.
2.2 Causes
The causes of a defective fuel pump actuator are as follows:
D Electrical interference (defective cable connections, broken cable etc.).
D A fuel pump actuator is defective.
2.3 Procedure
1) Connect the correct cable connections between the related CCM−20 and the fuel
pump actuator as soon as possible.
2014
Faults in High Pressure Fuel System
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