Engine JAC HFC4DA1-2C. Service manual — part 45
Maintenance manual for sunray hfc4da1-2c china-IV diesel engines
179
25.
DTC
P0401
Actual fresh air inflow is larger than target air inflow set by EGR system.
P0402
Actual fresh air inflow is smaller than target air inflow set by EGR system.
P0403
ECU internal drive module of EGR valve actuator control wire is
overheated.
P0404
EGR valve actuator control wire is open.
P0405
Voltage of EGR valve position sensor is below the lower limit (Connection is
short to ground).
P0406
Voltage of EGR valve position sensor is above the upper limit (Connection is
open short to high level).
P0489
EGR valve actuator control wire is open.
P0490
EGR valve actuator control wire is short to high level.
Fault Description: Exhaust gas recirculation system is applied in reduction of Nitrogen oxides emission due to high
temperature combustion. Main component of the system is electronic control exhaust gas recirculation valve. Exhaust
gas recirculation valve delivers a small amount of exhaust gas into intake manifold to reduce combustion temperature.
Recirculation gas flow is controlled by ECU according to changes in engine load. In the case of deceleration, gas flow
test for exhaust gas recirculation (EGR) system is carried out by ECU. Therefore, ECU gives a transient command to
open exhaust gas recirculation valve and simultaneously monitors signals of intake manifold air pressure (MAP)
sensor and exhaust gas recirculation position sensor. In the case of inconformity of intake manifold absolute pressure
signals with exhaust gas recirculation valve spool shaft position, ECU records measured D-value of intake manifold
absolute pressure and adjust calibrated failure counter to failure technical threshold value. For error quantities of
detected exhaust gas recirculation flow are different, required test times for exhaust gas recirculation flow concerned
excessive failure technical threshold value of may be different, too. When ECU detects incorrect control signals, DTC
occurs.
Diagnosis Hint: Carry out inspection to engine control system; check engine for historical faults; check exhaust gas
recirculation system for faults as follows—vacuum leaks between exhaust gas recirculation valve and intake manifold.
In the case of carbon deposition or exhaust gas noise around component faying surface, it is indicated there is external
leakage. Check passage and exhaust gas recirculation valve for clogging; check exhaust system for relevant faults
(such as leakage due to exhaust component damage, clogging due to excessive back pressure and too low engine
vacuum and etc.); finally, carry out inspection to mechanical system.
EGR5V Power supply
EGR position signal
EGR ground signal
EGR actuator power supply
EGR actuator ground
EGR position sensor
EGR actuator
Maintenance manual for sunray hfc4da1-2c china-IV diesel engines
180
Terminal ECU
K23
EGR position sensor 5V power supply
K31
EGR position sensor position signal
K39
EGR position sensor ground
A04
EGR actuator power supply
A19 EGR
actuator
ground
Maintenance manual for sunray hfc4da1-2c china-IV diesel engines
181
Fault Tree:
Repair accordingly.
Repair accordingly.
Repair the harness.
Get the Technical Support.
Replace components.
Does the problem still exist?
Electrical fault
Check for continuity and insulating property.
Replace the actuator.
Check ECU for connector faults.
Check actuator connectors.
Connector fault
Check actuator resistance.
Actuator resistance faults
Maintenance manual for sunray hfc4da1-2c china-IV diesel engines
182
26.
DTC
P0480
ECU Fan I control wire is open
P0481 ECU Fan II control wire is open.
P0483
ECU Fan I control wire internal drive module is overheated.
P0484
ECU Fan II control wire internal drive module is overheated.
P0691
ECU Fan I control wire is short to ground.
P0692
ECU Fan I control wire is short to high level.
P0693
ECU Fan II control wire is short to ground.
P0694
ECU Fan II control wire is short to high level.
Fault Description: ECU provides low-speed relay with grounding via so-called “drive” internal solid component in
order to control cooling fan low speed operation. For cooling fan high speed operation, ECU adopts the method of
high speed and S/P replay control circuit grounding with simultaneous low-speed control circuit grounding. Battery
positive voltage is provided to low-speed, high-speed and S/P fan relays. When ECU commands fan relay to be
connected, control circuit voltage is low level which is close to 0V. When ECU commands fan relay to be
disconnected, control circuit voltage should be high level which is close to battery voltage. ECU monitors relay
control circuit for conditions as follows:
It is short to ground.
It is short to voltage.
It is open.
When ECU detects incorrect voltage in low-speed or high-speed drive circuit, DTC occurs and corresponding drive
will stop operating.
Cooling Fan Relay I control circuit controls low-speed cooling fan relay.
Cooling Fan Relay II control circuit controls high-speed cooling fan relay.
Diagnosis Hint: Check harness for intermittency and good contact.
Prior to maintenance, remove all fragments from connector surface. Check connector pads for correct installation to
prevent contamination from entering prior to diagnosis and component replacement.
z Poor terminal connection—Check harness connectors for looseness, mismatching, retainer damage, improper
shape or damage and connection failure with wires. Apply corresponding matching terminals for test of proper
tension.
z Harness damage—Check wire harness for damage. In the case of no harness faults, move relevant connectors and
wire harness and observe display of fault diagnostic apparatus. Fault diagnostic apparatus displays changes to
indicate fault positions.
z Check ECU and engine ground connection for reliability and cleanness. If it is determined that DTC is an
intermittent fault, please refer to Fault Record to check the time of last DTC occurrence.
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