Cooling Fan Circuit (from 07/2011)

1NZ-FE COOLING: COOLING FAN SYSTEM (for Hatchback): Cooling Fan Circuit
- Cooling Fan Circuit

TECHNICAL DESCRIPTION

To control the cooling fans, the ECM turns on or off the cooling fan relays based on the engine coolant temperature, air conditioning switch, refrigerant pressure, engine speed and vehicle speed signals.

The ECM turns on or off the fan relays to switch the cooling fan motor circuit between the series circuit and parallel circuit, controlling the cooling fan motor speed in 2 steps.

WIRING DIAGRAM

Refer to System Diagram Description and Operation.

INSPECTION PROCEDURE

NOTICE:
Inspect the fuses for circuits related to this system before performing the following inspection procedure.

PROCEDURE

1. CHECK FAN NO. 1 RELAY (POWER SOURCE)

(a) Remove the FAN No. 1 relay from the engine room R/B.





(b) Measure the voltage according to the value(s) in the table below.

Standard Voltage:





Text in Illustration





(c) Reinstall the FAN No. 1 relay.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

2. CHECK ENGINE ROOM R/B

(a) Remove the FAN No. 1 relay and FAN No. 2 relay from the engine room R/B.





(b) Turn the Ignition switch to ON.

(c) Measure the voltage according to the value(s) in the table below.

Standard Voltage:





Text in Illustration





(d) Reinstall the FAN No. 1 relay and FAN No. 2 relay.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

3. 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.

4. 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.

5. INSPECT COOLING FAN RESISTOR

(a) Inspect the cooling fan resistor Testing and Inspection.

NG -- REPLACE COOLING FAN RESISTOR
OK -- Continue to next step.

6. CHECK HARNESS AND CONNECTOR (FAN NO. 2 RELAY - BODY GROUND)

(a) Remove the FAN No. 2 relay from the engine room R/B.

(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
OK -- Continue to next step.

7. CHECK HARNESS AND CONNECTOR (COOLING FAN RESISTOR - BODY GROUND)

(a) Disconnect the cooling fan resistor connector.

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:





(c) Connect the cooling fan resistor connector.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

8. CHECK HARNESS AND CONNECTOR (FAN NO. 2 RELAY - COOLING FAN RESISTOR)

(a) Disconnect the cooling fan resistor connector.

(b) Remove the FAN No. 2 relay from the engine room R/B.

(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. 2 relay.

(e) Reconnect the cooling fan resistor connector.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

9. CHECK COOLING FAN MOTOR

(a) Inspect the cooling fan motor Testing and Inspection.

NG -- REPLACE COOLING FAN MOTOR Removal (from 07/2011)
OK -- Continue to next step.

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

(a) Disconnect the cooling fan motor connector.

(b) Remove the FAN No. 1 relay from the engine room R/B.

(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.

(e) Reconnect the cooling fan motor connector.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

11. CHECK HARNESS AND CONNECTOR (COOLING FAN MOTOR - FAN NO. 2 RELAY)

(a) Disconnect the cooling fan motor connector.

(b) Remove the FAN No. 2 relay from the engine room R/B.

(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. 2 relay.

(e) Reconnect the cooling fan motor connector.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

12. CHECK HARNESS AND CONNECTOR (ENGINE ROOM R/B - ECM)

(a) Remove the FAN No. 1 relay and FAN No. 2 relay from the engine room R/B.

(b) Disconnect the ECM connector.

(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 ECM connector.

(e) Reinstall the FAN No. 1 relay and FAN No. 2 relay.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR

OK -- REPLACE ECM Removal (from 07/2011)