Inspection procedure 3
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 Initial Inspection and Diagnostic Overview).
STEP 1. Using scan tool MB991958, check the CAN bus line diagnostics.
Use scan tool to diagnose the CAN bus line Initial Inspection and Diagnostic Overview).
Q. Is the diagnostic trouble code set?
YES Go to Step 2.
NO Repair the CAN bus line CAN Bus Diagnostics Chart). 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 Scan Tool Testing and Procedures).
- Item 14: Cooling fan
Actuator Test Reference Table)
Q. Is the check result normal?
YES Go to Step 22.
NO Go to Step 3.
STEP 3. Using scan tool MB991958, read the MFI system DTC.
Using scan tool to read the MFI system DTC Reading and Clearing Diagnostic Trouble Codes).
Q. Is any DTC set?
YES Repair the MFI system Multiport Fuel Injection (MFI)). Then go to Step 23.
NO Go to Step 4.
STEP 4. Using scan tool MB991958, read the ASC system DTC.
Using scan tool to read the ASC system DTC Reading and Clearing Diagnostic Trouble Codes).
Q. Is any DTC set?
YES Repair the ASC system Active Stability Control System (ASC)). Then go to Step 23.
NO 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 Reading and Clearing Diagnostic Trouble Codes).
Q. Is any DTC set?
YES Repair the A/C system Heating and Air Conditioning). Then go to Step 23.
NO Go to Step 6.
STEP 6. Using scan tool MB991958, read the ETACS system DTC.
Using scan tool to read the ETACS system DTC Reading and Clearing Diagnostic Trouble Codes).
Q. Is any DTC set?
YES Repair the ETACS system Electronic Time and Alarm Control System (ETACS)). Then go to Step 23.
NO 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, and between ETACS-ECU connector C-312 terminal number 8 and body ground.
OK: Battery positive voltage
Q. Is the check result normal?
YES Go to Step 13.
NO 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.
Harness Connector Inspection.
Q. Is the connectors and terminals in good condition?
YES Go to Step 9.
NO 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?
YES Go to Step 10.
NO 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 8, for damage.
- Check harness wire for open/short circuit and damage.
Q. Is the harness wires in good condition?
YES Go to Step 11.
NO 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 Testing and Inspection.
Q. Is the relay in good condition?
YES Go to Step 12.
NO 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?
YES Go to Step 20.
NO 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.
Harness Connector Inspection.
Q. Is the connectors and terminals in good condition?
YES Go to Step 14.
NO 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?
YES Go to Step 15.
NO 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?
YES Go to Step 16.
NO 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?
YES Go to Step 17.
NO 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?
YES Go to Step 18.
NO 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 Testing and Inspection.
Q. Is the relay in good condition?
YES Go to Step 19.
NO Replace the damaged relay. Then go to Step 23.
STEP 19. Check the radiator fan motor and condenser fan motor.
Refer to Testing and Inspection.
Q. Is the fan motor in good condition?
YES Go to Step 20.
NO Replace the damaged fan motor (Refer to Service and Repair). 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 Reading and Clearing Diagnostic Trouble Codes).
Q. Is any DTC set?
YES Replace the ETACS-ECU Electronic Time and Alarm Control System (ETACS)-ECU Removal and Installation).
Then go to Step 23.
NO 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 Scan Tool Testing and Procedures).
- Item 14: Cooling fan
Actuator Test Reference Table)
Q. Is the check result normal?
YES Go to Step 22.
NO Replace the ECM [ Removal and Replacement].
Then go to Step 23.
STEP 22. Check the symptoms.
Q. Does the radiator fan and condenser fan operate normal?
YES An intermittent malfunction is suspected How to Cope With Intermittent Malfunctions).
NO Replace the ECM [ Removal and Replacement].
Then go to Step 23.
STEP 23. Check the symptoms.
Q. Does the radiator fan and condenser fan operate normal?
YES The procedure is complete.
NO Return to Step 1.