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Engine JAC HFC4DA1-2C. 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 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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