Inspection Procedure 25: Fan Control Relay System

OPERATION

The battery voltage is applied to the fan control relay (terminal No. 1) from the engine control relay (terminal No. 1) and is earthed to the vehicle body from the fan control relay (terminal No. 3).

The battery voltage is applied to the fan control relay (terminal No. 4).

When the fan control relay is in "ON" position, the battery voltage is supplied to the fan controller (terminal No. 3) from the fan control relay (terminal No. 2).

FUNCTION

When the engine control relay is in "ON" position, the fan control relay is also simultaneously placed in "ON" position. Accordingly, the battery voltage is supplied to the fan controller.

PROBABLE CAUSE

Failed fan control relay

Failed fan controller

Failed radiator fan motor

Failed condenser fan motor

Open/short circuit in fan control relay circuit or loose connector contact

Failed engine-A/T-ECU

DIAGNOSIS PROCEDURE

STEP 1. Connector check: A-10X fan control relay connector

Q: Is the check result normal?

YES: Go to Step 2

.
NO: Repair.

STEP 2. Check fan control relay.

Check fan control relay (Refer to GROUP 14 - On-Vehicle Service ).

Q: Is the check result normal?

YES: Go to Step 3

.
NO: Replace fan control relay.

STEP 3. Perform resistance measurement at A-10X fan control relay connector.

Remove relay, and measure at relay box side.

Resistance between terminal No. 3 and earth.

OK: 2 Ω or less

Q: Is the check result normal?

YES: Go to Step 4

.
NO:

Check and repair harness between A-10X (terminal No. 3) fan control relay connector and body earth.

Check earthing line for open circuit and damage.

STEP 4. Perform voltage measurement at A-10X fan control relay connector.

Remove relay, and measure at relay box side.

Ignition switch: ON

Voltage between terminal No. 1 and earth.

OK: System voltage

Q: Is the check result normal?

YES: Go to Step 6

.
NO: Go to Step 5

STEP 5. Connector check: B-17X engine control relay connector

Q: Is the check result normal?

YES:

Check intermediate connectors A-14 and C-17, and repair if necessary. If intermediate connectors are normal, check and repair harness between B-17X (terminal No. 1) engine control relay connector and A-10X (terminal No. 1) fan control relay connector.

Check power supply line for open/short circuit.

NO: Repair.

STEP 6. Perform voltage measurement at A-10X fan control relay connector.

Remove relay, and measure at relay box side.

Voltage between terminal No. 4 and earth.

OK: System voltage

Q: Is the check result normal?

YES: Go to Step 7

.
NO:

Check and repair harness between battery and A-10X (terminal No. 4) fan control relay connector.

Check power supply line for open/short circuit.

STEP 7. Connector check: A-20 fan controller connector

Q: Is the check result normal?

YES: Go to Step 8

.
NO: Repair.

STEP 8. Perform voltage measurement at A-20 fan controller connector.

Disconnect connector, and measure at harness side.

Ignition switch: ON

Voltage between terminal No. 3 and earth.

OK: System voltage

Q: Is the check result normal?

YES: Go to Step 12

.
NO: Go to Step 9

STEP 9. Check harness between A-10X (terminal No. 2) fan control relay connector and A-20 (terminal No. 3) fan controller connector.

Check output line for open/short circuit.

Q: Is the check result normal?

YES: Go to Step 10

.
NO: Repair.

STEP 10. Connector check: B-17X engine control relay connector

Q: Is the check result normal?

YES: Go to Step 11

.
NO: Repair.

STEP 11. Check harness between B-17X (terminal No. 1) engine control relay connector and A-10X (terminal No. 1) fan control relay connector.

NOTE: Before checking harness, check intermediate connectors A-14 and C-17, and repair if necessary.

Check power supply line for damage.

Q: Is the check result normal?

YES:

Check and repair harness between A-10X (terminal No. 3) fan control relay connector and body earth.

Check earthing line for damage.

NO: Repair.

STEP 12. Connector check: C-112 engine-A/T-ECU connector

Q: Is the check result normal?

YES: Go to Step 13

.
NO: Repair.

STEP 13. Fan motor drive test.

Disconnect C-112 engine-A/T-ECU connector.

Ignition switch: ON

OK: Fan motor rotates.

Q: Is the check result normal?

YES: Go to Step 14

.
NO: Go to Step 15

STEP 14. MUT-II/III actuator test

Item 21: Fan controller

OK: Fan motor rotates.

Q: Is the check result normal?

YES: Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points

).
NO: Replace engine-A/T-ECU.

STEP 15. Perform voltage measurement at C-112 engine-A/T-ECU connector.

Disconnect connector, and measure at harness side.

Ignition switch: ON

Voltage between terminal No. 18 and earth.

OK: 4.9 - 5.1 V

Q: Is the check result normal?

YES: Go to Step 16

.
NO: Go to Step 18

STEP 16. Check harness between A-10X (terminal No. 4) fan control relay connector and battery.

Check power supply line for damage.

Q: Is the check result normal?

YES: Go to Step 17

.
NO: Repair.

STEP 17. Check harness between A-10X (terminal No. 2) fan control relay connector and A-20 (terminal No. 3) fan controller connector.

Check output line for damage.

Q: Is the check result normal?

YES: Replace fan motor and fan controller.
NO: Repair.

STEP 18. Check harness between A-20 (terminal No. 2) fan controller connector and C-112 (terminal No. 18) engine-A/T-ECU connector.

NOTE: Before checking harness, check intermediate connector A-16, and repair if necessary.

Check output line for short circuit.

Q: Is the check result normal?

YES: Replace fan motor and fan controller.
NO: Repair.


Inspection Procedure 25: Fan Control Relay System

OPERATION The battery voltage is applied to the fan control relay (terminal No. 1) from the engine control relay (terminal No. 1) and is earthed to the vehicle body from the fan control relay (terminal No. 3). The battery voltage is applied to the fan control relay (terminal No. 4). When the fan control relay is in "ON" position, the battery voltage is supplied to the fan controller (terminal No. 3) from the fan control relay (terminal No. 2).
FUNCTION When the engine control relay is in "ON" position, the fan control relay is also simultaneously placed in "ON" position. Accordingly, the battery voltage is supplied to the fan controller.
PROBABLE CAUSE Failed fan control relay Failed fan controller Failed radiator fan motor Failed condenser fan motor Open/short circuit in fan control relay circuit or loose connector contact Failed engine-A/T-ECU
	DIAGNOSIS PROCEDURE

	STEP 1. Connector check: A-10X fan control relay connector
	Q: Is the check result normal? YES: Go to Step 2 . NO: Repair.
	STEP 2. Check fan control relay. Check fan control relay (Refer to GROUP 14 - On-Vehicle Service ). Q: Is the check result normal? YES: Go to Step 3 . NO: Replace fan control relay.
	STEP 3. Perform resistance measurement at A-10X fan control relay connector.
	Remove relay, and measure at relay box side. Resistance between terminal No. 3 and earth. OK: 2 Ω or less Q: Is the check result normal? YES: Go to Step 4 . NO: Check and repair harness between A-10X (terminal No. 3) fan control relay connector and body earth. Check earthing line for open circuit and damage.
	STEP 4. Perform voltage measurement at A-10X fan control relay connector.
	Remove relay, and measure at relay box side. Ignition switch: ON Voltage between terminal No. 1 and earth. OK: System voltage Q: Is the check result normal? YES: Go to Step 6 . NO: Go to Step 5 .
	STEP 5. Connector check: B-17X engine control relay connector
	Q: Is the check result normal? YES: Check intermediate connectors A-14 and C-17, and repair if necessary. If intermediate connectors are normal, check and repair harness between B-17X (terminal No. 1) engine control relay connector and A-10X (terminal No. 1) fan control relay connector. Check power supply line for open/short circuit. NO: Repair.
	STEP 6. Perform voltage measurement at A-10X fan control relay connector.
	Remove relay, and measure at relay box side. Voltage between terminal No. 4 and earth. OK: System voltage Q: Is the check result normal? YES: Go to Step 7 . NO: Check and repair harness between battery and A-10X (terminal No. 4) fan control relay connector. Check power supply line for open/short circuit.
	STEP 7. Connector check: A-20 fan controller connector
	Q: Is the check result normal? YES: Go to Step 8 . NO: Repair.
	STEP 8. Perform voltage measurement at A-20 fan controller connector.
	Disconnect connector, and measure at harness side. Ignition switch: ON Voltage between terminal No. 3 and earth. OK: System voltage Q: Is the check result normal? YES: Go to Step 12 . NO: Go to Step 9 .
	STEP 9. Check harness between A-10X (terminal No. 2) fan control relay connector and A-20 (terminal No. 3) fan controller connector.
	Check output line for open/short circuit. Q: Is the check result normal? YES: Go to Step 10 . NO: Repair.
	STEP 10. Connector check: B-17X engine control relay connector
	Q: Is the check result normal? YES: Go to Step 11 . NO: Repair.
	STEP 11. Check harness between B-17X (terminal No. 1) engine control relay connector and A-10X (terminal No. 1) fan control relay connector.
	NOTE: Before checking harness, check intermediate connectors A-14 and C-17, and repair if necessary. Check power supply line for damage. Q: Is the check result normal? YES: Check and repair harness between A-10X (terminal No. 3) fan control relay connector and body earth. Check earthing line for damage. NO: Repair.
	STEP 12. Connector check: C-112 engine-A/T-ECU connector
	Q: Is the check result normal? YES: Go to Step 13 . NO: Repair.
	STEP 13. Fan motor drive test.
	Disconnect C-112 engine-A/T-ECU connector. Ignition switch: ON OK: Fan motor rotates. Q: Is the check result normal? YES: Go to Step 14 . NO: Go to Step 15 .
	STEP 14. MUT-II/III actuator test Item 21: Fan controller OK: Fan motor rotates. Q: Is the check result normal? YES: Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points ). NO: Replace engine-A/T-ECU.
	STEP 15. Perform voltage measurement at C-112 engine-A/T-ECU connector.
	Disconnect connector, and measure at harness side. Ignition switch: ON Voltage between terminal No. 18 and earth. OK: 4.9 - 5.1 V Q: Is the check result normal? YES: Go to Step 16 . NO: Go to Step 18 .
	STEP 16. Check harness between A-10X (terminal No. 4) fan control relay connector and battery.
	Check power supply line for damage. Q: Is the check result normal? YES: Go to Step 17 . NO: Repair.
	STEP 17. Check harness between A-10X (terminal No. 2) fan control relay connector and A-20 (terminal No. 3) fan controller connector.
	Check output line for damage. Q: Is the check result normal? YES: Replace fan motor and fan controller. NO: Repair.
	STEP 18. Check harness between A-20 (terminal No. 2) fan controller connector and C-112 (terminal No. 18) engine-A/T-ECU connector.
	NOTE: Before checking harness, check intermediate connector A-16, and repair if necessary. Check output line for short circuit. Q: Is the check result normal? YES: Replace fan motor and fan controller. NO: Repair.