Engine JAC HFC4DA1-2C. Manual — part 33

Maintenance manual for sunray hfc4da1-2c china-IV diesel engines

131

Terminal ECU

A06

Power supply terminal of common rail pressure sensor

A52

Signal terminal of common rail pressure sensor

A40

Ground terminal of common rail pressure sensor

Maintenance manual for sunray hfc4da1-2c china-IV diesel engines

132

Fault Tree:

Read DTC.

Fault of fuel metering unit

Repair accordingly.

Check the common rail pressure

sensor.

Fault of common rail pressure

sensor

Repair accordingly.

Repair accordingly.

Fault of the low pressure oil

circuit

Fault of the high pressure oil

circuit

Repair the harness.

Get the Technical Support.

Check the low pressure oil circuit

by referring to fault tree of “Low

Pressure Oil Circuit”.

Maintenance manual for sunray hfc4da1-2c china-IV diesel engines

133

Inspection for Low Pressure/Hig

h Pressure Oil Circuit:

Low pressure oil circuit

Check fuel tank supply. Only checking the fuel tank

level indicator is not enough, for its indication may

be invalid.

Is there no fuel in the fuel tank?

Add fuel.

Check the status and function of manual pump.

Fault of manual pump

Repair accordingly.

Visually inspect the low pressure pipeline (leakage,

coordination, connection)

Repair accordingly.

Fault of low pressure pipeline

Ensure there is no air bubble in the low pressure oil

circuit.

Is there air in the oil circuit?

Find out where the air comes from

and repair the system, and then clean

the fuel pipe.

Ensure the diesel filter model and the connection of

fuel inlet and outlet are correct.

Incorrect signal or connection

Replace the current filter with the

original one or connect the inlet and

outlet pipes of filter correctly.

Repair accordingly.

High pressure oil circuit

Make diagnosis for the high pressure oil circuit in

strict accordance with the diagnostic procedures for

high pressure oil circuit.

Is there any problem?

The high pressure oil circuit is intact.

Maintenance manual for sunray hfc4da1-2c china-IV diesel engines

134

4.

DTC

P0116

The dynamic characteristics of coolant temperature sensor are unreliable.

P0117

The coolant temperature sensor output voltage is below the lower limit (the
wiring is short to ground).

P0118

The coolant temperature sensor output voltage is above the upper limit (the
wiring is open or short to high level).

P0119

The static characteristics of coolant temperature sensor are unreliable.

Fault Description: The engine coolant temperature (ECT) sensor is a kind of negative temperature coefficient
variable resistor, which can measure the engine coolant temperature. Its resistance shall decrease with the increase of
temperature, so the signal value input into ECU in the form of voltage shall decrease accordingly. The voltage signal
range is 0-5V. The ECU searches the characteristic curve of the sensor and converts it into engine coolant temperature.
The diagnostic module of engine coolant temperature sensor shall make fault judgment based on this temperature
value. The ECU shall supply 5V voltage to the signal circuit of engine coolant temperature sensor and also supply
grounding for the low reference voltage circuit. If the signal voltage of engine coolant temperature sensor detected by
ECU is too low (indicating the temperature is too high), or too high (indicating the temperature is too low), relevant
DTC shall be generated.

The following table illustrates the difference among temperature, resistance and voltage.

Engine coolant temperature

Resistance of coolant temperature

sensor

Signal voltage of coolant temperature

sensor

Low High High

High Low Low

Diagnosis Hint:

Overheating may result in generation of this DTC. After the engine is started, the temperature of engine coolant
temperature sensor should increase steadily and become stable after the thermostat is disconnected. Test the engine
coolant temperature sensor under different temperature to check for any error of sensor. If any, the error may result in
failure of control performance. After the engine is laid up for a night, the indication difference between IAT sensor and
engine coolant temperature sensor should be within 3°C (5°F). Refer to “Temperature and Resistance”.

Check for the following conditions:

Poor contact between ECU and engine coolant temperature sensor – Check the harness connector for:

− Loose terminal

− Poor matching and connection

− Breakage of keeper

− Distortion or damage of terminal

Coolant temperature

sensor

Coolant temperature

signal (High)

Coolant temperature

signal (Low)