Maintenance manual for sunray hfc4da1-2c china-IV diesel engines
85
z The fuel-water separator position sensor is installed on the bottom of the fuel filter;
z Wiring terminals: 1. Water level sensor; 2. Water level signal; 3. +12V power supply.
2) Working Principle
The grain substances are high-accuracy filtered by means of the interception and absorption of the filter medium and
the water concentrated on the filter medium is
separated by gravity force. The water separated
is deposited in the water chamber at the lower
portion of filter housing.
The water level sensor is installed at the lower
portion of water chamber. When the water level
reaches the sensing point of the sensor, the
internal circuit of sensor is actuated to output
signal to the ECU. At the same time, the signal is
transmitted to the instrument to light up the
water level alarm lamp.
3) Measurement analysis
Wiring terminals: 1 - Water level sensor; 2 - Water level signal; 3 - +12V power supply.
4) Malfunction Mode
z Short-circuit or open-circuit of sensor;
z Unstable sensor signal;
z Sensor signal is out of range.
1) Troubleshooting
Use Sunray special diagnosis instrument to check the trouble code and determine the malfunction position. Mainly
check the circuit of sensor and determine whether there is short-circuit or open-circuit between circuit and the
grounding wire, whether there is short-circuit or open-circuit to power supply, and whether the circuit is consistent
with the given pin definition.
8. Accelerator pedal position sensor
1) Overview
The accelerator pedal position sensor is mounted on
the accelerator pedal.
The accelerator pedal position sensor and the
accelerator pedal form one integral part. The
accelerator pedal position sensor internally
incorporates two same potentiometer sensors to
provide the driver’s driving demand signal to the ECU.
This process is completely same with the presently
mechanical pedal in terms of operation, in order to
adapt to the years of driving habit of the driver. Two
same sensors provide the accelerator signal to the
ECU respectively, which guarantees more safety and reliability of the system.
Wiring terminals: 1. +5V; 2. +5V; 3. Grounding of accelerator pedal 1; 4. Signal of accelerator pedal 1; 5. Grounding
of accelerator pedal 2; 6. Signal of accelerator pedal 2.
Signal terminal of
fuel-water separator
position sensor
Water level sensor of
fuel-water separator
Output voltage
Full close Full open
Open angle of accelerator pedal
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