Radiator Fan High Speed Circuit Troubleshooting (L4)

1.

Fuse check:

Fuse check

?1.

Check the following fuses.

Fuse	Location
No. A7 (15 A)	Under-hood fuse/relay box
No. A12-9 (30 A)
No. A23 (7.5 A)
No. B1 (7.5 A)	Under-dash fuse/relay box

Are the fuses OK?


	YES

Reinstall the fuses, then go to step 2.


	NO

Replace the fuse(s), and recheck. If the fuse(s) blows again, repair the short to ground on the No. A7 (15 A), No. A12-9 (30 A), No. A23 (7.5 A), and No. B1 (7.5 A) fuse circuit.?

2.

Relay check:

Relay check

?1.

Check the following relays.

Relay	Location
Radiator fan relay	Relay circuit board
Fan control relay	Relay circuit board

Are the relays OK?


	YES

Go to step 3.


	NO

Replace the relay circuit board.?

3.

Open wire check (+B MAIN FAN line):

Open wire check (+B MAIN FAN line)

?1.

Measure the voltage between test points 1 and 2.

Test condition	IG LOCK (0) or OFF mode
Test condition	Relay circuit board connector B (14P): disconnected
	Relay circuit board connector C (10P): disconnected
Test circuit	+B MAIN FAN
Test point 1	Relay circuit board connector B (14P) No. 7 (GRN)
Test point 2	Body ground

Is there battery voltage?


	YES

Go to step 4.


	NO

Repair an open in the +B MAIN FAN wire between the relay circuit board and the under-hood fuse/relay box, No. A12-9 (30A) fuse.?

4.

Determine possible failure area (GND line, others):

Determine possible failure area (GND line, others)

?1.

Connect terminals A and B with a jumper wire.

Terminal A	Relay circuit board connector B (14P) No. 6 (BLK)
Terminal B	Relay circuit board connector B (14P) No. 14 (PNK)

?2.

Connect terminals A and B with a jumper wire.

Terminal A	Relay circuit board connector B (14P) No. 1 (BLU)
Terminal B	Relay circuit board connector B (14P) No. 7 (GRN)

Does the radiator fan run at high speed?


	YES

Remove the jumper wires, then goo to step 9.


	NO

Remove the jumper wires, then goo to step 5.

5.

Radiator fan motor operation check:

Radiator fan motor operation check

?1.	Test the radiator fan motor.

Is the motor OK?


	YES

Go to step 6.


	NO

Replace the radiator fan motor.?

6.

Open wire check (GND line):

Open wire check (GND line)

?1.

Check for continuity between test points 1 and 2.

Test condition	IG LOCK (0) or OFF mode
	Relay circuit board connector B (14P): disconnected
	Relay circuit board connector C (10P): disconnected
Test circuit	GND
Test point 1	Relay circuit board connector B (14P) No. 6 (BLK)
Test point 2	Body ground

Is there continuity?


	YES

Go to step 7.


	NO

Repair an open in the GND wire between the relay circuit board and ground (G301).?

7.

Open wire check (MAIN FAN MOTOR line):

Open wire check (MAIN FAN MOTOR line)

?1.

Disconnect the flowing connector.

Radiator fan motor 2P connector

?2.

Check for continuity between test points 1 and 2.

Test condition	IG LOCK (0) or OFF mode
	Relay circuit board connector B (14P): disconnected
	Relay circuit board connector C (10P): disconnected
	Radiator fan motor 2P connector: disconnected
Test circuit	MAIN FAN MOTOR
Test point 1	Relay circuit board connector B (14P) No. 1 (BLU)
Test point 2	Radiator fan motor 2P connector No. 1 (BLU)

Is there continuity?


	YES

Go to step 8.


	NO

Repair an open in the MAIN FAN MOTOR wire between the relay circuit board and the radiator fan motor.?

8.

Open wire check (FAN HI/LO RLY COM line):

Open wire check (FAN HI/LO RLY COM line)

?1.

Check for continuity between test points 1 and 2.

Test condition	IG LOCK (0) or OFF mode
	Relay circuit board connector B (14P): disconnected
	Relay circuit board connector C (10P): disconnected
	Radiator fan motor 2P connector: disconnected
Test circuit	FAN HI/LO RLY COM
Test point 1	Relay circuit board connector B (14P) No. 14 (PNK)
Test point 2	Radiator fan motor 2P connector No. 2 (PNK)

Is there continuity?


	YES

Check for poor connections or loose terminals at the relay circuit board and the radiator fan motor.?


	NO

Repair an open in the FAN HI/LO RLY COM wire between the relay circuit board and the radiator fan motor.?

9.

Open wire check (IG2 A/C line) 1:

Open wire check (IG2 A/C line) 1

?1.	Turn the ignition switch to ON (II), or press the engine start/stop button to select the ON mode.

?2.

Measure the voltage between test points 1 and 2.

Test condition	IG ON (II) or ON mode
	Relay circuit board connector B (14P): disconnected
	Relay circuit board connector C (10P): disconnected
Test circuit	IG2 A/C
Test point 1	Relay circuit board connector C (10P) No. 8 (LT GRN)
Test point 2	Body ground

Is there battery voltage?


	YES

Go to step 10.


	NO

Repair an open in the IG2 A/C wire between the relay circuit board and the under-dash fuse/relay box.?

10.

Open wire check (FAN LO SIGNAL line):

Open wire check (FAN LO SIGNAL line)

?1.	Turn the ignition switch to LOCK (0), or press the engine start/stop button to select the OFF mode.

?2.	Connect the HDS to the DLC.

?3.	Turn the ignition switch to ON (II), or press the engine start/stop button to select the ON mode.

?4.	Make sure the HDS communicates with the vehicle. If it does not communicate, go to the DLC circuit trouble shooting.

?5.	Turn the ignition switch to LOCK (0), or press the engine start/stop button to select the OFF mode.

?6.	Jump the SCS line with the HDS. NOTE: This step must be done to protect the PCM from damage.

?7.

Disconnect the following connector.

PCM connector A (51P)

?8.

Check for continuity between test points 1 and 2.

Test condition	IG LOCK (0) or OFF mode
	Relay circuit board connector B (14P): disconnected
	Relay circuit board connector C (10P): disconnected
	PCM connector A (51P): disconnected
Test circuit	FAN LO SIGNAL
Test point 1	Relay circuit board connector B (14P) No. 8 (WHT)
Test point 2	PCM connector A (51P) No. 9 (WHT)

Is there continuity?


	YES

Go to step 11.


	NO

Repair an open in the FAN LO SIGNAL wire between the relay circuit board and the PCM.?

11.

Open wire check (FAN HI SIGNAL line):

Open wire check (FAN HI SIGNAL line)

?1.

Check for continuity between test points 1 and 2.

Test condition	IG LOCK (0) or OFF mode
	Relay circuit board connector B (14P): disconnected
	Relay circuit board connector C (10P): disconnected
	PCM connector A (51P): disconnected
Test circuit	FAN HI SIGNAL
Test point 1	Relay circuit board connector C (10P) No. 5 (YEL)
Test point 2	PCM connector A (51P) No. 10 (YEL)

Is there continuity?


	YES

Update the PCM if it does not have the latest software, or substitute a known-good PCM, then recheck. If the PCM was substituted, and the symptom/indication goes away, replace the original PCM.?


	NO

Repair an open in the FAN HI SIGNAL wire between the relay circuit board and the PCM.?