JAC HFC4DA1-2C engine. Service Manual — part 11

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

162

Fault Tree:

Check the battery voltage at

igniting.

Battery fault

Charge the battery.

Check the battery connection.

Fault of battery connectors

Repair accordingly.

Repair accordingly.

Check the ECU connector.

Connector fault

Check the resistance between chassis

and ECU ground.

Adjust the ECU ground.

Is the resistance too high?

Check the charging circuit of battery.

Fault of charging circuit

Repair accordingly.

Get the Technical Support.

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17.

DTC

P060A

Communication failure of ECU internal chip CJ940

Fault Description: It is mainly used for monitoring the internal microprocessor integrity failure in ECU to determine
whether the ECU program is executed. With engine OFF and ignition switch ON, the ECU shall perform
self-diagnosis. If the self-diagnosis process is not finished, the control module shall record the corresponding
operating condition and store this information into “Fault Records” to set DTC.

Diagnosis Hint: If the self-diagnosis process is finished smoothly, the current DTC shall be cleared.

If this diagnostic instrument and other diagnosis irrelevant to exhaust pass the test in 40 continuous preheating
processes, the history DTC shall be cleared.

Fault Tree:

Read DTC.

Replace the ECU with a good one for debugging.

Does the problem still exist?

Get the Technical Support.

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18.

DTC

P0642

Sensor supply voltage 1 is too low.

P0643

Sensor supply voltage 1 is too high.

P0652

Sensor supply voltage 2 is too low.

P0653

Sensor supply voltage 2 is too high.

Fault Description: Due to the nature of sensor, some sensors require a voltage to finish the required function and
operation. The supply voltage of sensor is supplied by ECU. The ECU shall calculate the required voltage of sensor
according to its characteristic and supply the voltage to the sensor via control circuit. In the process of voltage
signaling, DTCs may occur due to virtual connection or poor connection of control circuit, etc.

Sensor supply voltage 1: The power supply for accelerator pedal 1 and CMP sensor

Sensor supply voltage 2: The power supply for accelerator pedal 2, absolute pressure sensor and common rail
pressure sensor.

Diagnosis Hint: Check the ECU power voltage for any fault. The power voltage detected by multimeter should
generally be 5V. Check the voltage signal supplied to relevant sensor. The fault may be caused by virtual connection,
poor contact of wire, abrasion of insulation or damage of the wire in insulation. Check the circuit for the following
conditions:

– Loose terminal

– Poor matching and connection

– Breakage of keeper

– Distortion or damage of terminal

– Poor contact between terminal and wire

– Damage of harness – Check the harness for any damage

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Fault Tree:

Read DTC.

Read DTCs of all sensors corresponding

to the power connector

Match the connector correctly.

Provided that the signal lost is caused
by a certain sensor, disconnect each
sensor one by one until the fault
disappears and the failed sensor is
located. If all sensors are normal, check
for short circuit and the insulating
property of wires.

Does the problem still exist?

The problem is solved.

Get the Technical Support.

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19.

DTC

P0686

The main relay opens too early.

P0687

The main relay opens too late.

Fault Description: With the ignition switch OFF, the input circuit of main relay through K47 is actuated by V3 and
ECU Pin K46 and the electromagnet picks up the contact of output circuit, so the output circuit of main relay is in
continuity. Then, the power supply into the internal control module via ECU Pin K01, K03 and K05. If the ECU
signal for relay control is distorted, DTC shall be generated.

Diagnosis Hint: The intermittent failure may be caused by poor contact, abrasion of wire insulation or breakage of
the wire inside insulation. The ignition 1 relay fault shall lead to the failed starting of engine, for there is no voltage in
the ignition coil or fuel injectors in electronic ignition system and they cannot work without being electrified.

Terminal ECU

K47

Main relay control signal

Main relay

Power supply of main relay

Power supply of ignition switch

Control of main relay

Ignition
switch

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Fault Tree:

Check the relay connector.

Connector fault

Repair accordingly.

Check the ECU connector.

Connector fault

Repair accordingly.

Repair the harness.

Check continuity and insulating property.

Electrical fault

Replace the relay (running ISO
circulation.)

Fault of ISO circulation

Get the Technical Support.

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20.

DTC

P0704

Clutch signals are unreliable.

Fault Description: Transmission control unit (TCU) is integrated with engine control unit (ECU) and calculates
optimal time and speed for clutch engagement according to feedback information from sensors of accelerator pedal,
transmission gear position, transmission input/output shaft speed, engine speed, throttle opening and etc. Automatic
transmission (AT) actuating mechanism consists of electric oil pump, solenoid valve and clutch cylinder. When ECU
gives command to drive electric oil pump, high-pressure fluid generated in the pump goes through solenoid valve and
gets into clutch cylinder. ECU controls magnitude of current of solenoid valve for the control of fluid flow and fluid
passage change. Thus piston movement of clutch cylinder is realized in order to complete clutch operation during
vehicle starting and shift. In the case of inconformity between clutch signal and actual condition, DTC occurs.

Diagnosis Hint: clutch switch fault

Check switch wire harness (Check Terminal 58 of ECU for open circuit, short circuit and poor contact.)

Check switch power supply voltage and operation condition.

Determine ECU replacement according to actual condition.

Terminals ECU

K55 Clutch

switch

signal

Clutch switch

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Fault Tree:

Get the Technical Support.

Repair accordingly.

Repair the harness.

Replace the clutch switch.

Check clutch switch.

Clutch switch fault

Check clutch switch harness.

Harness fault

Check clutch switch power supply voltage.

Power supply signals are distorted.

Replace ECU and check

Does the problem still exist?

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21.

DTC P0650

There are faults (short circuit or open circuit) in ECU OBD malfunction
indicator lamp (MIL) output connecting wire.

P1619

Connection of ECU system MIL output connecting wire is short to high
level.

P161A

Connection of ECU system MIL output connecting wire is short to ground.

P161B

ECU system MIL output connecting wire is open.

P161C

ECU system MIL drive module is overheated.

Fault Description: Malfunction indicator lamps (MIL) are located on instrument panel cluster (IPC). MILs inform
driver about fault generation and necessary maintenance for engine control system. Control module monitors MIL
control circuit for inconformity of commands for MILs. For example, when MIL is disconnected by command, control
module monitors low voltage or when MIL is connected by command, control module monitors high voltage. This is
indicated that there are faults. When control module discovers incorrect voltage or overhigh temperature of MIL
control circuit, DTC occurs. In the case of 20 samplings for output status of MIL drive, open circuit or overhigh
temperature faults are detected in 15 samplings at least. There are 100msec for each sampling. ECU detects incorrect
output status or overlarge current of MIL drive and such status lasts for more than 2sec; for every 10 samplings of
MIL drive output status, there are short circuit faults in 5 samplings at least with time consumption for each sampling
process as 12.5msec and ECU detects short circuit for more than 1sec under MIL drive output status. In the case of
conditions above, DTCs occur.

Diagnosis Hint: When short circuit fault is detected, control module should stop starting MIL drive within remained
travel. Control module records operation condition when diagnosis is failed. For the first diagnosis failure, control
module will keep this information in fault record. If diagnosis failure occurs during the second continuous ignition
cycle, control module records operation condition under diagnosis failure and writes the operation condition in frozen
fault condition and updates fault record.

Terminal ECU

K70

System MIL output signal

K71 OBD

indicator

lamp

Malfunction indicator lamp (MIL)

OBD indicator lamp

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Fault Tree:

检查仪表板与ECU的连接

做必要的修理

接插件问题

检查连续性和绝缘性

Y

N

电气问题

Y

修理线束

更换相应的器件

N

问题仍存在

Y

联系技术支持

Get the Technical Support.

Repair the harness.

Repair accordingly.

Check connection between instrument panel and ECU.

Connector fault

Electrical fault

Check continuity and insulating property..

Replace corresponding components.

Does the problem still exist?

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22.

DTC P0100

Mass air flow (MAF) signals measured by air flow meter without correction
are too strong or too weak (Connection is in open circuit or short circuit).

P0101

Mass air flow (MAF) signals measured by air flow meter with correction are
too strong or too weak (Connection is in open circuit or short circuit).

P0102

Mass air flow sensor negative drift

P0103

Mass air flow sensor positive drift

P0104

Mass air flow sensor zero drift

P1100

Air mass flowmeter software correction is excessive.

Fault Description: Mass air flow (MAF) sensor is an air flow meter which is used in measurement of air inflow of
engine. ECU correctly supplies fuel supply with the use of signals from mass air flow sensor for all engine speeds and
loads. In the case of small air inflow of engine, it is indicated there is vehicle deceleration or engine idling. In the case
of large air inflow of engine, it is indicated there is vehicle acceleration or high engine load. Mass air flow (MAF)
sensor possesses circuits as follows:

One ignition 1 voltage circuit

One ground circuit

One signal circuit

ECU applies a voltage to sensor via signal circuit. The sensor uses the voltage to generate a corresponding frequency
for air inflow which gets through the sensor. During idle running, the frequency changes in the range around 2000Hz.
ECU calculates predicted air flow value with input signals from sensors as follows:

Atmosphere pressure in the case of ignition key connection

Intake manifold absolute pressure sensor

Intake air temperature sensor

Engine coolant temperature sensor

Engine speed

ECU compares mass air flow sensor frequency signal with predicted air flow valve and verify signal lag (lack of
change), too low or too high signal level under given operation condition with the comparison. When D-value
between actual mass air flow sensor frequency signal which is detected by ECU and air flow meter calculated value is
not in preconcerted range, DTC occurs.

Diagnosis Hint: Check mass air flow sensor harness and verify whether harness arrangement is too close to
components as follows:

Intake air temperature signal

Power supply

Intake air flow signal

Ground signal

Air flow meter

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— Additional accessories after sale

— Secondary ignition wires or coils

— Solenoid valve

— Relay

— Motor

In the case of idle running or deceleration, air flow goes through sensor may reach its minimum and this may lead to
DTC occurrence. Check down stream of mass air flow sensor for vacuum leaks. Check mass air flow sensing elements
for affixed dirt or scraps. Check intake system for water penetration. Once there is water in mass air flow sensor, it
will lead to sensor deviation and DTC occurrence.

Wide open throttle during vehicle acceleration for starting may lead to rapid parameter increase of mass air flow
sensor on fault diagnostic apparatus. In other words, 3-10g/sec during idle running will increase to 150g/sec for shift
from the 1

st

gear to the 2

nd

. If parameters do not increase, check intake system and exhaust system for clogging.

Check engine coolant temperature sensor for deviation or lag.

In the case of too high resistance in ignition 1 voltage circuit (i.e. equals to or more than 15Ω), DTC occurs.

Terminal ECU

K12

Intake air temperature signal

K20

Intake air flow signal

K63 Ground

signal

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Fault Tree:

检查空气流量计接插件

做必要的修理

接插件问题

做必要的修理

检查ECU接插件

接插件问题

检查连续性和绝缘性

Y

N

Y

N

电气问题

Y

修理线束

更换空气流量计

N

问题仍否存在

Y

联系技术支持

Get the Technical Support.

Repair the harness.

Repair accordingly.

Repair accordingly.

Check air flow meter connectors.

Connector fault

Check ECU connectors.

Does the problem still exist?

Connector fault

Electrical fault

Check for continuity and insulating property.

Replace air flow meter.

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23.

DTC P0110

Connection for additional air temperature sensor of air mass flowmeter is
short or open.

P0112

Temperature for additional air temperature sensor of air mass flowmeter is
too low.

P0113

Temperature for additional air temperature sensor of air mass flowmeter is
too high.

P1101

Analog output voltage for additional air temperature sensor of air mass
flowmeter is too high or too low.

P1102

Output duty ratio signal level of additional air temperature sensor of air
mass flowmeter is too high or too low.

P1106

Output duty ratio signal cycle of additional air temperature sensor of air
mass flowmeter is too long.

P1107

Output duty ratio signal cycle of additional air temperature sensor of air
mass flowmeter is too short.

Fault Description: Intake air temperature (IAT) sensor is a variable resistance for measurement of engine intake air
temperature. Air temperature sensor possesses a signal circuit and a low reference voltage circuit. ECU provides air
temperature sensor signal circuit with 5V voltage and provides air temperature sensor reference voltage circuit with
grounding. When air temperature sensor is under cold status, sensor resistance value is high. When air temperature
increases, sensor resistance value decreases. In the case of high sensor resistance, voltage of air temperature sensor
signal circuit detected by ECU is high. With decrease of sensor resistance, voltage of air temperature sensor signal
circuit detected by ECU reduces. In the case of too low detected air temperature signal voltage by ECU (it is indicated
that temperature is too high) or too high signal voltage (it is indicated that temperature is too low), DTC for this
occurs.

Differences among temperature, resistance and voltage are shown as the table below:

Temperature

Temperature Sensor Resistance

Temperature Sensor Signal Voltage

Low

High

High

High Low

Low

Diagnosis Hint: Test air temperature sensor under different temperatures for evaluation of sensor errors. In the case of
sensor error, there will be control performance fault. Lay the engine up for one night, D-value between air temperature
sensor and engine coolant temperature sensor displayed values should be within 3°C (5°F). Please refer to
“Temperature and Resistance”. In the case of too high resistance of temperature sensor signal circuit or low reference
voltage circuit, DTC may not occur.

Check for the following conditions:

Check ECU harness connector for poor contact between ECU and temperature sensor

− Terminal looseness

− Poor fit of matching parts

− Locking plate fracture

− Terminal deformation or damage

− Poor contact between terminal and wire

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Check harness damage. If the harness seems to be normal, move relevant connector and harness for intake air
temperature (IAT) sensor and check display about IAT on diagnostic tool. If display of IAT changes, it is indicated that
there is fault in the part.

Fault Tree:

检查传感器连接

做必要的修理

器件问题

更换传感器

检查传感器电阻（检查其是否与车辆

状态一致

接插件问题

检查连续性和绝缘性

Y

N

N

Y

检查是否为ECU插接件问题

Y

做必要的修理

N

电气问题

Y

修理线束

N

联系技术支持

Get the Technical Support.

Repair the harness.

Repair accordingly.

Repair accordingly.

Replace the sensor.

Check sensor connection.

Connector fault

Check sensor resistance (for conformity with vehicle

status).

Component fault

Check ECU for connector faults.

Check continuity and insulating property..

Electrical fault

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24.

DTC P0300

Multi-cylinder

misfire

P0301 The

1

st

cylinder misfire

P0302 The 2

nd

cylinder misfire

P0303 The

3

rd

cylinder misfire

P0304 The

4

th

cylinder misfire

Fault Description: ECU determines when engine misfire occurs with the help of information from ignition control
(IC) module and camshaft position (CMP) sensors. ECU can detect single misfire via crankshaft speed change for
each cylinder. In the case of some vehicle running condition, too high misfire rate will lead to three way catalytic
converter (TWC) overheating. In the case of three way catalytic converter overheating, MIL will flash. If misfire rate
detected by ECU is enough to make emission level to exceed mandatory standard, DTC occurs. If diagnosis operation
fails in two continuous ignition cycle, control module lightens MIL. Control module records operation condition when
diagnosis is failed. For the first diagnosis failure, control module will keep this information in fault record. If
diagnosis failure occurs during the successive ignition cycle, control module records operation condition under
diagnosis failure and writes the operation condition in frozen fault condition and updates fault record.

Diagnosis Hint: Influence factors for misfire diagnosis—In the case of misfire diagnosis, it is required that all
vehicle parts are under mass production or equivalent. All changes which may influence engine crankshaft speed will
interfere with correct diagnosis for misfire.

In the case of faults in components as follows, misfire diagnosis will pause to avoid incorrect diagnostic
results—intake pressure/throttle position rationality fault; low voltage or open circuit of intake pressure sensor circuit;
high voltage of intake pressure sensor circuit; low voltage or open circuit of coolant temperature sensor circuit; high
voltage of coolant temperature sensor circuit; high voltage of throttle position sensor; low voltage of throttle position
sensor; signal interference of crankshaft position sensor circuit; no signals in crankshaft position sensor circuit; no
signals in camshaft position sensor circuit; camshaft position sensor rationality fault; high voltage or open circuit of
intake air temperature sensor circuit; low voltage of intake air temperature sensor circuit; no signals in vehicle speed
sensor.

Severe vibration which is not caused by engine may lead to setting fault (vibration source may lead to wears or
damages to brake discs with different thicknesses and additional drive belts).