2.8.7.7 Cooling Fan always Runs at Low Speed 

Note: Before carry out this diagnostic procedures, please refer to the2.8.7.2 Cooling Fan Circuit 
Diagnosis, which will facilitate the Diagnostic. 

1 

Use the “Action Test” of fault diagnosis tester to drive the fan high-speed. Is 
low-speed relay 2 working? 

Is High- or Low-speed relay 2 working? 

 

2 

Inspect the grounding circuit between the socket #87 of the cooling fan’s high-speed 
and low-speed relay 2 and the vehicle body. 

 

(a)  Rotated ignition switch to "OFF" 

position . 

(b)  Dismantle the high- or low-speed 

relay 2. 

(c)  Measure the grounding resistance 

between the relay 2 socket #87 
and the body with multimeter. 

Standard Resistance: Less than 1 Ω 

Confirm whether the resistance is 
normal. 

NL11-2264b

ER03

8 5

86

8 7

30

3 0

87

8 6

8 5

ER05

3 0

8 7

86

85

ER06

30

87

87 a

8 6

8 5

ER11

ER08

ER

09

8 5

8 6

87

3 0

4

ER10

2

1

5

3

4

2

1

5

3

4

2

1

5

3

ER04

4

ER02

2

1

5

3

4

2

1

5

3

ER01

ER07

4

2

1

5

3

1

2

3

4

11

12

13

14

15

16

5

6

7

8

9

10

EF0

8

EF0

7

EF2

7

EF2

6

EF2

2

EF2

9

EF

0

3

EF

0

6

EF

0

9

EF2

5

EF1

7

EF1

6

EF1

5

EF

3

5

EF2

1

EF1

4

EF

01

EF

02

EF

04

EF

10

EF

1

1

EF1

8

EF2

4

87

 

3 

Check the open circuit fault at the grounding with the vehicle body of the socket 87 of 
the cooling fan’s high- and low-speed relay 2. 

 

4 

Inspect high-speed or low-speed relay 2 coil circuit. 

(a)  Rotated ignition switch to "OFF" position . 

(b)  Dismantle the cooling fan high- or low-speed relay 2. 

(c)  Rotated ignition switch to "ON" position . 

(d)  Connect fault diagnosis tester to the diagnostic interface. 

Yes 

Go to step 6 

No 

No 

Go to step 4 

Yes 

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(e)  Select in sequence: Engine/Action Test/Fan High Speed. 

(f)  Measure the voltage between the #85 and #86 sockets of the high-speed relay with 

multimeter. 

(e)  Standard Voltage: 11-14 V 

Confirm if the voltage conforms to standard value. 

 

5 

Repair the open circuit fault of the fuse relay box in the engine compartment and 
replace it if necessary. 

6 

Use the “Action Test” of fault diagnosis tester to drive the fan low-speed. 

Is the low-speed relay working? 

 

7 

Inspect the high-speed and low-speed relay 1 socket No.30    input power supply. 

(a)  Rotated ignition switch to "OFF" position . 

(b)  Dismantle the cooling fan high- or low-speed relay 1. 

(c)  Measure voltage between high- or low-speed cooling fan relay 1 socket No.30 and a reliable 

ground. 

Standard Voltage: 11-14 V 

Confirm if the voltage conforms to standard value. 

 

8 

Inspect high-speed or low-speed cooling fan relay 1 and cooling fan harness connector 
CA09 wiring harnesses. 

(a)  Rotated ignition switch to "OFF" position . 

(b)  Dismantle the cooling fan high- or low-speed relay 1. 

(c)  Disconnect cooling fan wiring harness connector CA09. 

(d)  Test continuity between high-speed or low-speed cooling fan relay 1 terminal No.87 and 

cooling fan wiring harness connector CA09 terminal No.1. 

(e)  Measure resistance between high-speed cooling fan relay 1 terminal No.87 and a reliable 

ground. Inspect whether the circuit is short to ground. 

No 

Inspect and repair the faulty locations and replace 
the underhood fuse relay box if necessary. 

Yes 

Yes 

Go to step 11 

No 

Yes 

Replace high- or low-speed relay 2 

No 

556

Standard Value 

Test Items 

Specified Value 

High or low-Speed relay 1(87)-CA09(1) 

Less than 1 Ω 

Resistance High- or Low-Speed Between Relay 
1 (87) and A Reliable Ground 

10 kΩ or higher 

Confirm whether the resistance conforms to standard value. 

 

9 

Inspect the resistance between the terminal 2 of the harness connector CA09 of the 
cooling fan 1 and the socket 30 of the cooling fan’s high- or low-speed relay 2. 

 

(a)  Rotated ignition switch to "OFF" 

position . 

(b)  Disconnect cooling fan 1 wiring 

harness connector CA09. 

(c)  Dismantle the high- or low-speed 

cooling fan relay 2. 

(d)  Use the multimeter to check the 

resistance between the terminal 2 
of the harness connector CA09 of 
the cooling fan 1 and the socket 
30 of the cooling fan’s 
high-speed or low-speed relay 2. 

Standard Resistance: Less than 1 Ω 

NL02-2255b

1

2

CA09 冷却风扇电机1线束连接器

2

Confirm whether the resistance conforms to standard value. 

 

10 

Replace Fan Motor 1 

 

11 

Inspect High- or Low-speed relay 1 coil power supply. 

(a)  Rotated ignition switch to "OFF" position . 

(b)  Dismantle the fan high- or low-speed relay 1. 

(c)  Rotated ignition switch to "ON" position . 

No 

Repair the circuit fault between the terminal 2 of the 
harness connector CA09 of the cooling fan 1 and the socket 
30 of the cooling fan’s high- or low-speed relay 2. 

Yes 

No 

Inspect and repair the faulty locations between the 
high-speed or low-speed relay 1 terminal No.87 and the 
cooling fan wiring harness connector CA09 terminal No.1. 

Yes 

CA09cooling fan motor 1harness 

connector 

557

(d)  Measure the effective grounding voltage between High- or Low-speed relay 1 socket 85 and 

the body with a multimeter. 

Standard Voltage: 11-14 V 

Confirm if the voltage conforms to standard value. 

 

12 

Measure ECM harness connector EM01 terminal No.65 voltage. 

(a)  Rotated ignition switch to "ON" position . 

(b)  Disconnect ECM harness connector EM01. 

(c)  Dismantle the high- or low-speed cooling fan relay 1. 

(d)  Test the continuity between the cooling fan high- or low-speed relay 1 terminal No.86 and 

EM01 terminal No.65. 

Standard Resistance: Less than 1 Ω 

Confirm whether the measured value conforms to the standard value. 

 

13 

Inspect ECM working circuit. 

(a)  Check if ECM power circuit is normal. 

(b)  Inspect if ECM ground is normal. 

 

14 Replace 

ECM 

 

15 Troubleshooting 

Next 

No 

Repair the faulty part.   

Yes 

No 

Repair the open circuit fault between the high- or 
low-speed relay 1 terminal #86 and EM01 terminal #65. 

Yes 

No 

Replace high- or low-speed relay 1 and repair the 
underhood fuse relay box. Replace it if necessary. 

Yes 

558