Engine JAC HFC4DA1-2C. Manual — part 41

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

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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.

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

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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

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

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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.

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

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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