Cooling Fan Circuit

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

Cooling Fan Circuit

DESCRIPTION

The ECM calculates an appropriate cooling fan speed based on the engine coolant temperature, air conditioning switch condition, refrigerant pressure, engine speed, and vehicle speed and sends the signals to the cooling fan ECU to regulate the cooling fan. The cooling fan ECU controls the cooling fan speed based on the duty ratio signal sent from the ECM. By basing its control on the operating conditions, the ECM can control the fan speed optimally using the cooling fan ECU, achieving both high cooling performance and quietness.

WIRING DIAGRAM

INSPECTION PROCEDURE

PROCEDURE

1. PERFORM ACTIVE TEST USING TECHSTREAM (CONTROL COOLING FAN)
(a) Connect the Techstream to the DLC3.
(b) Turn the ignition switch to ON.
(c) Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Electric Cooling Fan.
(d) Check that the cooling fan can be operated using the Techstream.
OK:

Result:

C -- CHECK HARNESS AND CONNECTOR (ECM - COOLING FAN ECU)
B -- INSPECT COOLING FAN ECU
A -- PROCEED TO NEXT INSPECTION PROCEDURE SHOWN IN PROBLEM SYMPTOMS TABLE
2. INSPECT COOLING FAN ECU

(a) Disconnect the ECM connector.
(b) Turn the ignition switch to ON.
(c) Check that the cooling fan operates.
OK:
The cooling fan operates.
(d) Reconnect the ECM connector.
NG -- CHECK HARNESS AND CONNECTOR (ECM - COOLING FAN ECU)
OK -- REPLACE ECM
3. CHECK HARNESS AND CONNECTOR (ECM - COOLING FAN ECU)
(a) Disconnect the cooling fan ECU connector.

(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) Reconnect the cooling fan ECU connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (ECM - COOLING FAN ECU)
OK -- Continue to next step.

4. INSPECT COOLING FAN MOTOR

(a) Disconnect the cooling fan ECU connector.
(b) Connect a battery positive (+) lead to terminal 2 of the cooling fan motor connector, and connect a battery negative (-) lead to terminal 1 of the cooling fan motor connector.
(c) Check that the cooling fan motor operates.
OK:
The cooling fan operates.
(d) Reconnect the cooling fan ECU connector.
NG -- REPLACE COOLING FAN MOTOR
OK -- Continue to next step.

5. CHECK COOLING FAN ECU (POWER SOURCE)

(a) Disconnect the cooling fan ECU 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 cooling fan ECU connector.
NG -- CHECK HARNESS AND CONNECTOR (COOLING FAN ECU - BODY GROUND)
OK -- REPLACE COOLING FAN ECU
6. CHECK HARNESS AND CONNECTOR (COOLING FAN ECU - BODY GROUND)

(a) Disconnect the cooling fan ECU connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:

(c) Reconnect the cooling fan ECU connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (COOLING FAN ECU - BODY GROUND)
OK -- Continue to next step.

7. INSPECT FAN NO. 1 RELAY

(a) Remove the FAN No. 1 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. 1 relay.
NG -- REPLACE FAN NO. 1 RELAY
OK -- Continue to next step.

8. INSPECT FUSIBLE LINK BLOCK (RDI FAN FUSE)
(a) Check the RDI FAN fuse.
NG -- REPLACE FUSIBLE LINK BLOCK
OK -- Continue to next step.

9. INSPECT FUSE (ECU-IG NO. 1)

(a) Remove the ECU-IG No. 1 fuse from the driver side 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.

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

(a) Disconnect the cooling fan ECU connector.
(b) Remove the FAN No. 1 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 cooling fan ECU connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (COOLING FAN ECU - FAN NO. 1 RELAY)
OK -- Continue to next step.

11. CHECK HARNESS AND CONNECTOR (FAN NO. 1 RELAY - BODY GROUND)

(a) Remove the FAN No. 1 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. 1 relay.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (FAN NO. 1 RELAY - BODY GROUND)
OK -- Continue to next step.

12. CHECK HARNESS AND CONNECTOR (FAN NO. 1 RELAY - ECU-IG NO. 1 FUSE)

(a) Remove the ECU-IG No. 1 fuse from the driver side junction block.
(b) Remove the FAN No. 1 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) Reinstall the ECU-IG No. 1 fuse.
(e) Reinstall the FAN No. 1 relay.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (FAN NO. 1 RELAY - ECU-IG NO. 1 FUSE)
OK -- Continue to next step.

13. CHECK HARNESS AND CONNECTOR (FAN NO. 1 RELAY - RDI FAN FUSE)
(a) Remove the fusible link block assembly from the engine room relay block.
(b) Disconnect the fusible link block connector.

Standard Resistance (Check for Short):

(d) Reconnect the fusible link block connector.
(e) Reinstall the fusible link block assembly.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (FAN NO. 1 RELAY - RDI FAN FUSE)
OK -- REPAIR OR REPLACE HARNESS OR CONNECTOR (BATTERY - RDI FAN FUSE)
14. CHECK HARNESS AND CONNECTOR (ECM - COOLING FAN ECU)
(a) Disconnect the cooling fan ECU connector.

(b) Disconnect the ECM connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:

(d) Reconnect the ECM connector.
(e) Reconnect the cooling fan ECU connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (ECM - COOLING FAN ECU)
OK -- REPLACE COOLING FAN ECU