Inspection Procedure 3: Radiator Fan and Condenser Fan do not Operate

CIRCUIT OPERATION

The engine control module (ECM) transmits the rotation signals of radiator fan and condenser fan, based on the engine coolant temperature signal from the engine coolant temperature sensor, the vehicle speed signal from the wheel speed sensor via the ASC-ECU, and the A/C switch signal from the A/C-ECU using the CAN bus line.
The rotation signals of radiator fan and condenser fan, using the CAN bus line from ECM, turn ON/OFF of the radiator fan relay, condenser fan relay, and fan control relay via ETACS-ECU, to control the radiator fan and condenser fan rotation.

TECHNICAL DESCRIPTION

When the radiator fan and condenser fan do not operate, the wiring harness/connector, fan motor, relay, and ETACS-ECU may have a failure.
The radiator fan and condenser fan do not operate also when the CAN bus line, MFI system, or ETACS system have a failure.

TROUBLESHOOTING HINTS

Malfunction of CAN bus line.
Damaged wiring harness or connector.
Malfunction of MFI system.
Malfunction of ASC system.
Malfunction of the A/C system.
Malfunction of ETACS system.
Malfunction of fusible link number 28.
Malfunction of fusible link number 29.
Malfunction of radiator fan relay.
Malfunction of condenser fan relay.
Malfunction of fan control relay.
Malfunction of radiator fan motor.
Malfunction of condenser fan motor.
Malfunction of ETACS-ECU.
Malfunction of ECM.

DIAGNOSTIC PROCEDURE

Required Special Tools:

MB991958: Scan Tool (M.U.T.-III Sub Assembly)

MB991824: V.C.I.
MB991827: M.U.T.-III USB Cable
MB991910: M.U.T.-III Main Harness A

MB991223: Harness Set
MB992006: Extra Fine Probe

caution

If there is any problem in the CAN bus lines, an incorrect diagnostic trouble code (DTC) may be set. Prior to this diagnosis, diagnose the CAN bus lines (Refer to GROUP 54C, Trouble code diagnosis

STEP 1. Using scan tool MB991958, check the CAN bus line diagnostics.

Use scan tool to diagnose the CAN bus line (Refer to GROUP 54C, Explanation About The Scan Tool Can Bus Diagnostics

Q. Is the diagnostic trouble code set?

	Go to Step 2.

	Repair the CAN bus line (Refer to GROUP 54C, Diagnosis - Can Bus Diagnostic Table ). Then go to Step 23.

STEP 2. Using scan tool MB991958, check the MFI system actuator test.

Using scan tool to check the MFI system actuator test (Refer to GROUP 13A, MFI Diagnosis - Diagnostic Function

Item 14: Cooling fan
(Refer to GROUP 13A, MFI Diagnosis - Actuator Test Reference Table )

Q. Is the check result normal?

	Go to Step 22.

	Go to Step 3.

STEP 3. Using scan tool MB991958, read the MFI system DTC.

Using scan tool to read the MFI system DTC (Refer to GROUP 13A, MFI Diagnosis - Diagnostic Function

Q. Is any DTC set?

	Repair the MFI system (Refer to GROUP 13A, MFI Diagnosis - Diagnostic Trouble Code Chart ). Then go to Step 23.

	Go to Step 4.

STEP 4. Using scan tool MB991958, read the ASC system DTC.

Using scan tool to read the ASC system DTC (Refer to GROUP 35C, Diagnosis - Diagnostic Function

Q. Is any DTC set?

	Repair the ASC system (Refer to GROUP 35C, Diagnosis - Diagnostic Trouble Code Chart .) Then go to Step 23.

	Go to Step 5.

STEP 5. Using scan tool MB991958, read the A/C system DTC.

Using scan tool to read the A/C system DTC (Refer to GROUP 55, Auto A/C Diagnosis - Diagnostic Function

Q. Is any DTC set?

	Repair the A/C system (Refer to GROUP 55, Auto A/C Diagnosis - Diagnostic Trouble Code Chart .) Then go to Step 23.

	Go to Step 6.

STEP 6. Using scan tool MB991958, read the ETACS system DTC.

Using scan tool to read the ETACS system DTC (Refer to GROUP 54A, ETACS, Troubleshooting - Diagnostic Function

Q. Is any DTC set?

	Repair the ETACS system (Refer to GROUP 54A, ETACS, Troubleshooting - Diagnostic Trouble Code Chart ). Then go to Step 23.

	Go to Step 7.

STEP 7. Measure the terminal voltage at ETACS-ECU connector C-312.

(1)Disconnect the ETACS-ECU connector C-312, and measure at front wiring harness connector side.

(2)Turn the ignition switch to the "ON" position.

(3)Measure the terminal voltage between ETACS-ECU connector C-312 terminal number 2 and body ground, between ETACS-ECU connector C-312 terminal number 8 and body ground, and between ETACS-ECU connector C-312 terminal number 9 and body ground.
OK: Battery positive voltage

Q. Is the check result normal?

Go to Step 13.

Go to Step 8.

STEP 8. Check the radiator fan relay connector A-35X, condenser fan relay connector A-36X, fan control relay connector A-37X, and ETACS-ECU connector C-312, for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Refer to GROUP 00E, Harness Connector Inspection

Q. Is the connectors and terminals in good condition?

	Go to Step 9.

	Repair or replace the damaged connector. Then go to Step 23.

STEP 9. Check the harness wire between fusible link number 28 and condenser fan relay connector A-36X terminal number 3, between fusible link number 28 and condenser fan relay connector A-36X terminal number 4, between condenser fan relay connector A-36X terminal number 4 and fan control relay connector A-37X terminal number 1, and between fusible link number 29 and radiator fan relay connector A-35X terminal number 3, for damage.

Check harness wire for open/short circuit and damage.

Q. Is the harness wires in good condition?

Go to Step 10.

Repair or replace the damaged harness wire. Then go to Step 23.

STEP 10. Check the harness wire between radiator fan relay connector A-35X terminal number 1 and ETACS-ECU connector C-312 terminal number 2, between condenser fan relay connector A-36X terminal number 1 and ETACS-ECU connector C-312 terminal number 8, and between fan control relay connector A-37X terminal number 3 and ETACS-ECU connector C-312 terminal number 9, for damage.

Check harness wire for open/short circuit and damage.

Q. Is the harness wires in good condition?

	Go to Step 11.

	Repair or replace the damaged harness wire. Then go to Step 23.

STEP 11. Check the radiator fan relay, condenser fan relay, and fan control relay.

Refer to

Q. Is the relay in good condition?

	Go to Step 12.

	Replace the damaged relay. Then go to Step 23.

STEP 12. Check the fusible link number 28 and fusible link number 29.

Q. Is the fusible link in good condition?

	Go to Step 20.

	Replace the damaged fusible link. Then go to Step 23.

STEP 13. Check the radiator fan relay connector A-35X, condenser fan relay connector A-36X, fan control relay connector A-37X, radiator fan motor connector A-45, and condenser fan motor connector A-47, for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Refer to GROUP 00E, Harness Connector Inspection

Q. Is the connectors and terminals in good condition?

	Go to Step 14.

	Repair or replace the damaged connector. Then go to Step 23.

STEP 14. Check the harness wire between fusible link number 28 and condenser fan relay connector A-36X terminal number 4, and between fusible link number 29 and radiator fan relay connector A-35X terminal number 4, for damage.

Check harness wire for open/short circuit and damage.

Q. Is the harness wires in good condition?

	Go to Step 15.

	Repair or replace the damaged harness wire. Then go to Step 23.

STEP 15. Check the harness wire between radiator fan relay connector A-35X terminal number 2 and radiator fan motor connector A-45 terminal number 1, and between condenser fan relay connector A-36X terminal number 2 and condenser fan motor connector A-47 terminal number 1, for damage.

Check harness wire for open/short circuit and damage.

Q. Is the harness wires in good condition?

	Go to Step 16.

	Repair or replace the damaged harness wire. Then go to Step 23.

STEP 16. Check the harness wire between radiator fan motor connector A-45 terminal number 2 and fan control relay connector A-37X terminal number 2, and between condenser fan motor connector A-47 terminal number 2 and body ground, for damage.

Check harness wire for open/short circuit and damage.

Q. Is the harness wires in good condition?

	Go to Step 17.

	Repair or replace the damaged harness wire. Then go to Step 23.

STEP 17. Check the harness wire between fan control relay connector A-37X terminal number 4 and condenser fan motor connector A-47 terminal number 1, and between fan control relay connector A-37X terminal number 5 and body ground, for damage.

Check harness wire for open/short circuit and damage.

Q. Is the harness wires in good condition?

	Go to Step 18.

	Repair or replace the damaged harness wire. Then go to Step 23.

STEP 18. Check the radiator fan relay, condenser fan relay, and fan control relay.

Refer to

Q. Is the relay in good condition?

	Go to Step 19.

	Replace the damaged relay. Then go to Step 23.

STEP 19. Check the radiator fan motor and condenser fan motor.

Refer to

Q. Is the fan motor in good condition?

	Go to Step 20.

	Replace the damaged fan motor (Refer to .) Then go to Step 23.

STEP 20. Using scan tool MB991958, read the ETACS system DTC.

Using scan tool to read the ETACS system DTC (Refer to GROUP 54A, ETACS, Troubleshooting - Diagnostic Function

Q. Is any DTC set?

	Replace the ETACS-ECU (Refer to GROUP 54A, ETACS - ETACS-ECU .) Then go to Step 23.

	Go to Step 21.

STEP 21. Using scan tool MB991958, check the MFI system actuator test.

Using scan tool to check the MFI system actuator test (Refer to GROUP 13A, MFI Diagnosis - Diagnostic Function

Item 14: Cooling fan
(Refer to GROUP 13A, MFI Diagnosis - Actuator Test Reference Table )

Q. Is the check result normal?

	Go to Step 22.

	Replace the ECM [Refer to GROUP 13A, Engine Control Module (ECM) .] Then go to Step 23.

STEP 22. Check the symptoms.

Q. Does the radiator fan and condenser fan operate normal?

	An intermittent malfunction is suspected (Refer to GROUP 00, How to use troubleshooting - How to Cope with Intermittent Malfunction ).

	Replace the ECM [Refer to GROUP 13A, Engine Control Module (ECM) .] Then go to Step 23.

STEP 23. Check the symptoms.

Q. Does the radiator fan and condenser fan operate normal?

	The procedure is complete.

	Return to Step 1.