Engine Cooling Fan System (Diagnostics & Circuit Tests): Other Lexus IS III

PRECAUTION [04/2013 - ]

1. PRECAUTION FOR DISCONNECTING CABLE FROM NEGATIVE BATTERY TERMINAL NOTE: When disconnecting the cable from the negative (-) battery terminal, initialize the following system after the cable is reconnected. System Name See Procedure Variable Gear Ratio Steering System Refer to «INITIALIZATION [04/2013 - ]»(ref-665529-S01115916402014102400000) Air Conditioning System

Scheme 1

Scheme 2

PROCEDURE

1. INSPECT COOLING FAN SYSTEM Connect the Techstream to the DLC3. Turn the engine switch on (IG). Turn the Techstream on. Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Electric Cooling Fan. Powertrain > Engine > Active Test Tester Display Control the Electric Cooling Fan Check the operation of the cooling fan while operating it using the Techstream. If the cooling fan motor does not operate, check the cooling fan circuit. Refer to «Cooling Fan Circuit [04/2013 - ]»(ref-665786-S33151498952014102400000)

CAUTION / NOTICE / HINT

Note. Inspect the fuses for circuits related to this system before performing the following procedure.

Scheme 3

1. PERFORM ACTIVE TEST USING GTS (Control the Electric Cooling Fan) Connect the Techstream to the DLC3. Turn the engine switch on (IG). Turn the Techstream on. Enter the following menus: Powertrain / Engine / Active Test / Control the Electric Cooling Fan. Powertrain > Engine > Active Test Tester Display Control the Electric Cooling Fan Check the operation of the cooling fans while operating them using the Techstream. OK Tester Operation Fan Operation ON Cooling fans operate OFF Cooling fans stop Result Result Proceed to OK A NG (Cooling fans do not operate) B NG (Cooling fans do not stop) C Result: 1 A PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to «PROBLEM SYMPTOMS TABLE [04/2013 - ]»(ref-665786-S24748372362014102400000) Result: 3 C See step 10 Result: 2 B See step 2
2. INSPECT COOLING FAN MOTOR (COOLING FAN MOTOR AND NO. 2 COOLING FAN MOTOR) Inspect the cooling fan motor and No. 2 cooling fan motor. Refer to «ON-VEHICLE INSPECTION [04/2013 - ]»(ref-665707-S35633675662014102400000) Result Result Proceed to OK A NG (Cooling fan motor) B NG (No. 2 cooling fan motor) C Result: 2 B REPLACE COOLING FAN MOTOR. Refer to «REMOVAL [04/2013 - ]»(ref-665707-S04003876012014102400000) Result: 3 C REPLACE NO. 2 COOLING FAN MOTOR. Refer to «REMOVAL [04/2013 - ]»(ref-665707-S04003876012014102400000) Result: 1 A See step 3
3. CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT) Disconnect the A42 cooling fan ECU connector. Turn the engine switch on (IG). Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Condition Specified Condition A42-3(+B1) - A42-1(E1) Engine switch on (IG) 11 to 14 V *a Front view of wire harness connector (to Cooling Fan ECU) Reconnect the A42 cooling fan ECU connector. Result Result OK NG Result: 2 NG See step 5 Result: 1 OK See step 4
4. CHECK HARNESS AND CONNECTOR (ECM - COOLING FAN ECU) Disconnect the A76 ECM connector. Disconnect the A42 cooling fan ECU connector. Measure the resistance according to the value(s) in the table below. Standard Resistance (Check for Short) Tester Connection Condition Specified Condition A76-19(RFC) or A42-2(SI) - Body ground Always 10 kohms or higher Reconnect the A42 cooling fan ECU connector. Reconnect the A76 ECM connector. Result Result OK NG Result: 1 OK REPLACE COOLING FAN ECU Result: 2 NG REPAIR OR REPLACE HARNESS OR CONNECTOR
5. CHECK HARNESS AND CONNECTOR (COOLING FAN ECU - BODY GROUND) Disconnect the A42 cooling fan ECU connector. Measure the resistance according to the value(s) in the table below. Standard Resistance (Check for Open) Tester Connection Condition Specified Condition A42-1(E1) - Body ground Always Below 1 ohms Reconnect the A42 cooling fan ECU connector. Result Result OK NG Result: 2 NG REPAIR OR REPLACE HARNESS OR CONNECTOR Result: 1 OK See step 6
6. INSPECT FAN RELAY Inspect the FAN relay. Refer to «ON-VEHICLE INSPECTION [04/2013 - ]»(ref-665707-S41739985202014102400000) Result Result OK NG Result: 2 NG REPLACE FAN RELAY Result: 1 OK See step 7
7. INSPECT NO. 2 ENGINE ROOM RELAY BLOCK AND NO. 2 JUNCTION BLOCK ASSEMBLY (FAN RELAY) Remove the FAN relay from the No. 2 engine room relay block and No. 2 junction block assembly. Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Condition Specified Condition 3 (FAN relay) - Body ground Always 11 to 14 V *1 No. 2 engine room relay block and No. 2 junction block assembly *2 FAN Relay Reinstall the FAN relay. Result Result OK NG Result: 2 NG REPAIR OR REPLACE HARNESS OR CONNECTOR Result: 1 OK See step 8
8. CHECK HARNESS AND CONNECTOR (COOLING FAN ECU - FAN RELAY) Disconnect the A42 cooling fan ECU connector. Remove the FAN relay from the No. 2 engine room relay block and No. 2 junction block assembly. Measure the resistance according to the value(s) in the table below. Standard Resistance (Check for Open) Tester Connection Condition Specified Condition A42-3(+B1) - 5 (FAN relay) Always Below 1 ohms Standard Resistance (Check for Short) Tester Connection Condition Specified Condition A42-3 (+B1) or 5 (FAN relay) - Body ground Always 10 kohms or higher Reinstall the FAN relay. Reconnect the A42 cooling fan ECU connector. Result Result OK NG Result: 2 NG REPAIR OR REPLACE HARNESS OR CONNECTOR Result: 1 OK See step 9
9. CHECK HARNESS AND CONNECTOR (FAN RELAY - BODY GROUND) Remove the FAN relay from the No. 2 engine room relay block and No. 2 junction block assembly. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition 2 (FAN relay) - Body ground Always Below 1 ohms Reinstall the FAN relay. Result Result OK NG Result: 1 OK REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT) Result: 2 NG REPAIR OR REPLACE HARNESS OR CONNECTOR (FAN RELAY - BODY GROUND)
10. CHECK HARNESS AND CONNECTOR (ECM - COOLING FAN ECU) Disconnect the A76 ECM connector. Disconnect the A42 cooling fan ECU connector. Measure the resistance according to the value(s) in the table below. Standard Resistance (Check for Open) Tester Connection Condition Specified Condition A76-19(RFC) - A42-2(SI) Always Below 1 ohms Reconnect the A42 cooling fan ECU connector. Reconnect the A76 ECM connector. Result Result OK NG Result: 2 NG REPAIR OR REPLACE HARNESS OR CONNECTOR Result: 1 OK See step 11
11. CHECK HARNESS AND CONNECTOR (COOLING FAN MOTOR - BODY GROUND) Disconnect the z10 cooling fan motor connector. Measure the resistance according to the value(s) in the table below. Standard Resistance (Check for Short) Tester Connection Condition Specified Condition z10-1(M-) - Body ground Always 10 kohms or higher *a Component without harness connected (Cooling fan motor) Reconnect the z10 cooling fan motor connector. Result Result OK NG Result: 2 NG REPLACE COOLING FAN MOTOR. Refer to «REMOVAL [04/2013 - ]»(ref-665707-S04003876012014102400000) Result: 1 OK See step 12
12. CHECK HARNESS AND CONNECTOR (NO. 2 COOLING FAN MOTOR - BODY GROUND) Disconnect the z9 No. 2 cooling fan motor connector. Measure the resistance according to the value(s) in the table below. Standard Resistance (Check for Short) Tester Connection Condition Specified Condition z9-1(M-) - Body ground Always 10 kohms or higher *a Component without harness connected (No. 2 cooling fan motor) Reconnect the z9 No. 2 cooling fan motor connector. Result Result OK NG Result: 1 OK REPLACE COOLING FAN ECU Result: 2 NG REPLACE NO. 2 COOLING FAN MOTOR. Refer to «REMOVAL [04/2013 - ]»(ref-665707-S04003876012014102400000)