Cooling Fan Circuit

2AZ-FE COOLING: COOLING FAN SYSTEM: Cooling Fan Circuit

Cooling Fan Circuit

DESCRIPTION

The ECM turns on or off the fan relays using signals calculated from the engine coolant temperature, air conditioning (ON/OFF), air conditioner refrigerant pressure, engine speed, and vehicle speed signals.
The ECM switches the circuit of the cooling fan motors between series and parallel by turning on or off the fan relays in order to control the speed of the cooling fan motors in two steps.

WIRING DIAGRAM





INSPECTION PROCEDURE
NOTE: After replacing the ECM, the new ECM needs registration Programming and Relearning.

PROCEDURE

1. PERFORM ACTIVE TEST USING TECHSTREAM (OPERATE ELECTRIC COOLING FAN)
(a) Connect the Techstream to the DLC3.
(b) Turn the ignition switch to ON.
(c) Turn the Techstream on.
(d) Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Electric Cooling Fan.
OK:






Result:






C -- INSPECT FAN NO. 1 RELAY
B -- INSPECT ECM (FANL AND FANH VOLTAGE)
A -- PROCEED TO NEXT INSPECTION PROCEDURE SHOWN IN PROBLEM SYMPTOMS TABLE
2. INSPECT ECM (FANL AND FANH VOLTAGE)




(a) Disconnect the ECM connector.
(b) Turn the ignition switch to ON.
(c) Measure the voltage according to the value(s) in the table below.
Standard Voltage:





(d) Reconnect the ECM connector.
NG -- CHECK FUSE (ECU-IG NO. 1 FUSE)
OK -- Continue to next step.

3. INSPECT ENGINE ROOM RELAY BLOCK (FAN NO. 1 RELAY AND FAN NO. 3 RELAY VOLTAGE)




(a) Remove the FAN No. 1 relay and FAN No. 3 relay from the engine room relay block.
(b) Measure the voltage according to the value(s) in the table below.
Standard Voltage:





(c) Reinstall the FAN No. 1 relay and FAN No. 3 relay.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (BATTERY - ENGINE ROOM RELAY BLOCK)
OK -- Continue to next step.

4. INSPECT FAN NO. 1 RELAY
(a) Inspect the FAN No. 1 relay Testing and Inspection.
NG -- REPLACE FAN NO. 1 RELAY
OK -- Continue to next step.

5. INSPECT FAN NO. 2 RELAY
(a) Inspect the FAN No. 2 relay Testing and Inspection.
NG -- REPLACE FAN NO. 2 RELAY
OK -- Continue to next step.

6. INSPECT FAN NO. 3 RELAY
(a) Inspect the FAN No. 3 relay Testing and Inspection.
NG -- REPLACE FAN NO. 3 RELAY
OK -- Continue to next step.

7. CHECK HARNESS AND CONNECTOR (ENGINE ROOM RELAY BLOCK - BODY GROUND)




(a) Remove the FAN No. 2 relay from the engine room relay block.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:





(c) Reinstall the FAN No. 2 relay.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (ENGINE ROOM RELAY BLOCK - BODY GROUND)
OK -- Continue to next step.

8. INSPECT NO. 1 COOLING FAN MOTOR (RADIATOR FAN MOTOR)
(a) Inspect the No. 1 cooling fan motor Testing and Inspection.
NG -- REPLACE NO. 1 COOLING FAN MOTOR (RADIATOR FAN MOTOR)
OK -- Continue to next step.

9. CHECK HARNESS AND CONNECTOR (NO. 1 COOLING FAN MOTOR - BODY GROUND)




(a) Disconnect the No. 1 cooling fan motor (radiator fan motor) connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:





(c) Reconnect the No. 1 cooling fan motor connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (NO. 1 COOLING FAN MOTOR - BODY GROUND)
OK -- Continue to next step.

10. CHECK HARNESS AND CONNECTOR (NO. 1 COOLING FAN MOTOR - ENGINE ROOM RELAY BLOCK)




(a) Disconnect the No. 1 cooling fan motor (radiator fan motor) connector.
(b) Remove the FAN No. 1 relay and FAN No. 2 relay from the engine room relay block.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance (Check for Open):






Standard Resistance (Check for Short):





(d) Reconnect the radiator fan motor connector.
(e) Reinstall the FAN No. 1 relay and FAN No. 2 relay.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (NO. 1 COOLING FAN MOTOR - ENGINE ROOM RELAY BLOCK)
OK -- Continue to next step.

11. INSPECT NO. 2 COOLING FAN MOTOR (AIR CONDITIONER CONDENSER FAN MOTOR)
(a) Inspect the No. 2 cooling fan motor Testing and Inspection.
NG -- REPLACE NO. 2 COOLING FAN MOTOR (AIR CONDITIONER CONDENSER FAN MOTOR)
OK -- Continue to next step.

12. CHECK HARNESS AND CONNECTOR (NO. 2 COOLING FAN MOTOR - ENGINE ROOM RELAY BLOCK)




(a) Disconnect the No. 2 cooling fan motor (air conditioner condenser fan motor) connector.
(b) Remove the FAN No. 2 relay and FAN No. 3 relay from the engine room relay block.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance (Check for Open):






Standard Resistance (Check for Short):





(d) Reconnect the No. 2 cooling fan motor connector.
(e) Reinstall the FAN No. 2 relay and FAN No. 3 relay.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (NO. 2 COOLING FAN MOTOR - ENGINE ROOM RELAY BLOCK)
OK -- Continue to next step.

13. INSPECT ENGINE ROOM RELAY BLOCK (FAN NO. 1 RELAY - FAN NO. 2 RELAY)




(a) Remove the FAN No. 1 relay and FAN No. 2 relay from the engine room relay block.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance (Check for Open):






Standard Resistance (Check for Short):





(c) Reinstall the FAN No. 1 relay and FAN No. 2 relay.
NG -- REPLACE ENGINE ROOM RELAY BLOCK
OK -- REPLACE ECM
14. CHECK FUSE (ECU-IG NO. 1 FUSE)




(a) Remove the ECU-IG No. 1 fuse from the instrument panel junction block.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:





(c) Reinstall the ECU-IG No. 1 fuse.
NG -- REPLACE FUSE (ECU-IG NO. 1 FUSE)
OK -- Continue to next step.

15. INSPECT FAN NO. 1 RELAY
(a) Inspect the FAN No. 1 relay Testing and Inspection.
NG -- REPLACE FAN NO. 1 RELAY
OK -- Continue to next step.

16. INSPECT FAN NO. 2 RELAY
(a) Inspect the FAN No. 2 relay Testing and Inspection.
NG -- REPLACE FAN NO. 2 RELAY
OK -- Continue to next step.

17. INSPECT FAN NO. 3 RELAY
(a) Inspect the FAN No. 3 relay Testing and Inspection.
NG -- REPLACE FAN NO. 3 RELAY
OK -- Continue to next step.

18. CHECK HARNESS AND CONNECTOR (ENGINE ROOM RELAY BLOCK - ECM)




(a) Remove the FAN No. 1 relay, FAN No. 2 relay and FAN No. 3 relay from the engine room relay block.
(b) Disconnect the ECM connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance (Check for Open):





(d) Reinstall the FAN No. 1 relay, FAN No. 2 relay and FAN No. 3 relay.
(e) Reconnect the ECM connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (ENGINE ROOM RELAY BLOCK - ECM)
OK -- Continue to next step.

19. CHECK HARNESS AND CONNECTOR (ECU-IG NO. 1 FUSE - ENGINE ROOM RELAY BLOCK)




(a) Remove the FAN No. 1 relay, FAN No. 2 relay and FAN No. 3 relay from the engine room relay block.




(b) Remove the ECU-IG No. 1 fuse from the instrument panel junction block.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance (Check for Open):






Standard Resistance (Check for Short):





(d) Reinstall the FAN No. 1 relay, FAN No. 2 relay and FAN No. 3 relay.
(e) Reinstall the ECU-IG No. 1 fuse.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (ECU-IG NO. 1 FUSE - ENGINE ROOM RELAY BLOCK)
OK -- REPLACE ECM
20. INSPECT FAN NO. 1 RELAY
NG -- REPLACE FAN NO. 1 RELAY
OK -- Continue to next step.

21. INSPECT FAN NO. 3 RELAY
NG -- REPLACE FAN NO. 3 RELAY
OK -- Continue to next step.

22. CHECK HARNESS AND CONNECTOR (ENGINE ROOM RELAY BLOCK - ECM)




(a) Remove the FAN No. 1 relay, FAN No. 2 relay and FAN No. 3 relay from the engine room relay block.
(b) Disconnect the ECM connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance (Check for Short):





(d) Reinstall the FAN No. 1 relay, FAN No. 2 relay and FAN No. 3 relay.
(e) Reconnect the ECM connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (ECU-IG NO. 1 FUSE - ENGINE ROOM RELAY BLOCK)
OK -- REPLACE ECM