12

01

29

Main Relay

Cooling Fan Low Speed Relay

Cooling Fan High 

Speed Relay

Cooling Fan Assembly

Engine 

Control 

Module

FE02-7800b

Engine

Cooling System JL4G18-D

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2.8.7 Diagnostic Information and Procedures
2.8.7.1 Diagnosis Description

Refer to 

2.8.2.1

 

Description and Operation

Get familiar with the system functions and operation before start system diagnostics, so

that it will help to determine the correct diagnostic steps, more importantly, it will also help to determine whether the customer
described situation is normal.

2.8.7.2 Cooling Fan Circuit Diagnosis

Diagnostic Tips:

–

If  a  customer  complains  an  overheating  fault,  verify  whether  it  is  because  the  engine  coolant  boiling  or  the  engine  coolant
temperature gage is indicating overheating. If the engine is overheated, but the cooling fan still runs normally, check the engine
cooling system.

–

If the underhood fuse EF29 fuses immediately after installation, check whether the cooling fan high and low speed relay and
cooling fan motor wire is short to ground. If the fuse fuses immediately after the engine control module pull-in, then the cooling
fan motor may be faulty.

–

When the air-conditioning system is running, the engine control module controls the cooling fan running at low speed. When the
air-conditioning high pressure reaches 1,520 kPa (220.5 psi), the engine cooling fan control module will switch the cooling fan
from low to high speed. When the air-conditioning high pressure drops back to 1,450 kPa (210.3 psi), the cooling fan will return
low-speed.

–

Scan tool can be used in the "Function Test" to drive high or low speed cooling fan relay pull-in. Check whether the fan works
normally in order to quickly determine the fault.

Note

Before carry out this diagnostic procedures, check whether the underhood fuse EF29 is normal and main relay is
working properly. When use scan tool "Action Test", make sure the scan tool communication with ECM is normal.

Step 1

Verify the fault.

Next

Step 2

Confirm whether the Low-Speed cooling fan runs.

(a)

Turn the ignition switch to "OFF" position.

(b)

Connect scan tool to the datalink connector.

(c)

Start the engine to normal working temperature.

(d)

Turn off the A/C switch.

(e)

Select in sequence: Engine / Data List / Engine Coolant
Temperature.

(f)

When the engine coolant temperature displays 95°C
(203 ºF) the cooling fan should be running at low speed.

Does the low speed cooling fan run?

No

Refer to 

2.8.7.4

 

Low-Speed Cooling Fan Does

Not Run

Yes

Step 3

Confirm whether the high-speed cooling fan runs.

(a)

Turn off the A/C switch.

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Cooling System JL4G18-D

Engine

(b)

When the engine coolant temperature displays 102°C
(215.6 ºF) The cooling fan should be running at high speed.

Does the high speed cooling fan run?

No

Refer to 

2.8.7.3

 

High-Speed Cooling Fan

Does Not Run

Yes

Step 4

Turn on the A/C switch, confirm whether the Low-Speed cooling fan runs.

(a)

Turn the ignition switch to "OFF" position.

(b)

Connect scan tool to a datalink connector.

(c)

Select in sequence: Engine / Data List / Engine Coolant
Temperature.

(d)

When the engine coolant temperature is below 90°C
(194 ºF) Start the engine, turn on the A/C switch, cooling fan
should be running at low speed.

Does the low speed cooling fan run?

No

A/C system fault. Refer to

8.2.7

 

Diagnostic

Information and Procedures

Yes

Step 5

Intermittent Fault. Refer to 

2.2.7.3

 

Intermittent Fault Check

.

2.8.7.3 High-Speed Cooling Fan Does Not Run

Note

Before carry out this diagnostic procedures, please Refer to the2.8.7.2

 

Cooling Fan Circuit Diagnosis, which will facilitate

the Diagnostic.

Step 1

check the high-speed cooling fan power supply .

1

2

3

Cooling Fan Harness Connector CA16

FE02-7801b

(a)

Turn the ignition switch to "OFF" position.

(b)

Disconnect cooling fan wiring harness connector CA16.

(c)

Turn the ignition switch to "ON" position.

(d)

Connect scan tool to the datalink connector.

(e)

Select in sequence: Engine / Action Test / Fan 2.

(f)

Make the high-speed relay work.

(g)

Measure voltage between CA16 cooling fan wiring harness
connector terminal No.2 and a reliable ground.

Standard Voltage: 11-14 V

Is the voltage specified Value?

No

Go to step 4

Yes

Step 2

Check the cooling fan ground circuit.

Engine

Cooling System JL4G18-D

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1

2

3

Cooling Fan Harness Connector CA16

FE02-7802b

(a)

Turn the ignition switch to "OFF" position.

(b)

Disconnect cooling fan wiring harness connector CA16.

(c)

Measure resistance between cooling fan wiring harness
connector CA16 terminal No.3 and a reliable ground.

Standard Resistance: Less than 1 Ω

Is the resistance specified Value?

No

CA16 terminal No.3 poor connection to
ground. inspect and repair faulty parts.

Yes

Step 3

Replace the cooling fan assembly.

Step 4

Use scan tool "Action Test" to drive the fan 2. Does the High-Speed relay work?

No

Go to step 8

Yes

Step 5

Check the high-speed relay A terminal No.87 input power supply.

1413 12 1110

5

1

2

3

4

6

7

8

9

J

L

K

I

G

D

C

B

E

F

A

86

86

30

87

85

86

86

87

87

87

30

30

30

85

85

85

2

2

3

3

5

5

1

1

1

2

5 3

1

2

5 3

86

87

30

1

1

2

5
3

2

5
3

85

EF01

EF21

EF18

EF25

EF20

EF29

EF06

EF02

EF30

EF17

EF19

EF23

EF22

EF26

EF24

EF08

EF27

EF28

EF05

EF07

EF16

EF04

EF03

EF15

EF12

EF10

EF1

1

EF09

EF13

EF14

EF32

EF31

A

86

87

30

85

FE02-7803b

(a)

Turn the ignition switch to "OFF" position.

(b)

Remove the high-speed cooling fan relay A.

(c)

Measure voltage between high-speed cooling fan relay A
terminal No.87 and a reliable ground.

Standard Voltage: 11-14 V

Is the voltage specified Value?

No

Relay A terminal No.87 circuit is faulty.
inspect and repair the faulty parts

Yes

Step 6

Check the fan high-speed relay A wiring harness and cooling fan harness connector CA16 wiring harness..

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