Engine JAC HFC4DA1-2C. Manual — part 48

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

191

Fault Tree:

Get the Technical Support.

Repair the harness.

Repair accordingly.

Check connection between instrument

panel and ECU.

Connector fault

Check for continuity and insulating

property.

Electrical fault

Replace corresponding components.

Does the problem still exist?

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

192

31.

DTC

P2228

Atmosphere pressure sensor output voltage is too low.

P2229

Atmosphere pressure sensor output voltage is too high.

Fault Description: Atmosphere pressure indicates connection of ignition switch. When engine stops operation,
control module calculates atmosphere pressure with signals sent by intake manifold absolute pressure sensor. Intake
manifold absolute pressure sensor responses to internal pressure changes of intake manifold and the pressure changes
according to different engine loads. Intake manifold absolute pressure sensor possesses circuits as follows:

5V reference voltage circuit

Low reference voltage circuit

Intake manifold absolute pressure sensor signal circuit

ECU provides intake manifold absolute pressure sensor with 5V voltage via 5V reference voltage circuit. ECU
supplies grounding via low reference voltage circuit and intake manifold absolute pressure sensor provides ECU with
a signal via signal circuit. This signal is related to intake manifold internal pressure changes. When ignition switch is
connected and engine is shut down, intake manifold absolute pressure sensor displays signals of atmosphere pressure.
In the case of engine running with wide open throttle, reading of atmosphere pressure will be renewed. ECU
determines whether voltage exceeds normal range via detecting intake manifold absolute pressure sensor signals.
When intake manifold absolute pressure sensor displays atmosphere pressure, if sensor signal voltage is not in
specified range, DTC occurs.

Diagnosis Hint: When ignition switch is connected and engine is shut down, intake manifold pressure equals to
atmosphere pressure and signal voltage is low level. ECU takes this information as vehicle elevation indication.
Moreover, to make comparison between this reading with that of an intact vehicle which possesses the same sensor is
a good method for sensor accuracy inspection. D-value of two readings should not exceed 0.4V. It is necessary to
carry out comprehensive inspection to pressure source of supercharger pressure sensor in order to check intake system
for clogging.

In the case of engine start, intake manifold absolute pressure sensor can detect any change of manifold pressure. This
test is carried out to determine sensor lag at a certain value.

In the case of normal intake manifold absolute pressure sensor, it will make rapid response to changes of acceleration
pedal positions and it should not be “lagged” or slower than changes of acceleration pedal position.

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

193

Fault Tree:

Get the Technical Support.

Repair the harness.

Repair accordingly.

Check sensor connection.

Connector fault

Check sensor resistance (for conformity with

vehicle status).

Electrical fault

Sensor resistance faults

Does the problem still exist?

Repair accordingly.

Check ECU for connector faults.

Replace the sensor.

Check continuity and insulating property

Replace components.

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

194

32.

DTC

P2264

There are faults in water level sensor of diesel filter oil-water separator.

P2267 Water in diesel filter oil-water separator is overflowed.

Fault Description: Main function of oil-water separator is to separate moisture from oil in fuel to ensure combustion
quality of fuel. When fuel oil goes through oil-water separator, oil content and moisture content in the fuel are
separated. For water density is larger than that of oil, separated water is stored in “water tank” under filter element.
Fuel filter lower water level sensor is applied in water level detection in “water tank”. When accumulated water
reaches certain level, warning lamp on instrument panel will be lightened to remind driver to carry out draining. In the
case of delayed water drainage, DTC occurs.

Diagnosis Hint: In the case of DTC existence, it is necessary to check water level first of all. Normally, carry out
water drainage for every 8000-10000km engine running. For oil quality problems, water drainage should be carried
out ahead of time for fuel which contains much moisture. Besides, test relevant connectors for this diagnostic
procedure for short circuit of terminals or poor contact of wire, avoiding water level sensor signal distortions caused
by short circuit or poor contact.

Water level signal

Drain switch