Heated Steering Wheel (Diagnostics & Symptom Tests): Diagnosis Lexus RX III рестайлинг

HOW TO PROCEED WITH TROUBLESHOOTING [03/2012 - ]

HINT

Use these procedures to troubleshoot the heated steering wheel system.

1. VEHICLE BROUGHT TO WORKSHOP NEXT: Go to next step
2. INSPECT BATTERY VOLTAGE Standard voltage 11 to 14 V If the voltage is below 11 V, recharge or replace the battery before proceeding to the next step. NEXT: Go to next step
3. PROBLEM SYMPTOMS TABLE RESULT Result Proceed to Fault is not listed in problem symptoms table A Fault is listed in problem symptoms table B B --> Go to step 5 A: Go to next step
4. OVERALL ANALYSIS AND TROUBLESHOOTING Terminals of ECU. Refer to «TERMINALS OF ECU [03/2012 - ]»(ref-602779-S17173054702014030500000) NEXT: Go to next step
5. REPAIR OR REPLACE NEXT: Go to next step
6. CONFIRMATION TEST NEXT --> END

PROBLEM SYMPTOMS TABLE [03/2012 - 07/2012]

HINT

Use the table below to help determine the cause of problem symptoms. If multiple suspected areas are listed, the potential causes of the symptoms are listed in order of probability in the "Suspected Area" column of the table. Check each symptom by checking the suspected areas in the order they are listed. Replace parts as necessary.

HEATED STEERING WHEEL SYSTEM

PROBLEM SYMPTOMS TABLE [07/2012 - ]

HINT

Use the table below to help determine the cause of problem symptoms. If multiple suspected areas are listed, the potential causes of the symptoms are listed in order of probability in the "Suspected Area" column of the table. Check each symptom by checking the suspected areas in the order they are listed. Replace parts as necessary.

HEATED STEERING WHEEL SYSTEM

Scheme 77

1. CHECK HEATED STEERING WHEEL CONTROLLER HINT: Inspect the connectors from the back side while the connectors are connected. Measure the voltage or resistance according to the value(s) in the table below. Terminal No. (Symbol) Terminal Description Condition Specified Condition A-1 (CCU) - Body ground LED output signal Engine switch on (IG), Steering heater switch on Below 3 V A-2 (CCV) - Body ground Steering heater switch input signal Engine switch on (IG), Steering heater switch pressed and held 11 to 14 V A-3 (CCX) - Body ground Ground Always Below 1 ohms A-4 (CCW) - Body ground IG power supply Engine switch on (IG) 11 to 14 V B-1 (TH1) - Body ground Thermistor input signal Engine switch on (IG), Steering heater switch on at 0 to 40°C (32 to 104°F) 1.5 to 4.5 V*1 B-2 (TH2) - Body ground Thermistor ground Engine switch on (IG), Steering heater switch on Below 1 V B-3 (SH2) - Body ground Heater output signal Engine switch on (IG), Steering heater switch on 11 to 14 V*2 B-4 (SH1) - Body ground Heater ground Engine switch on (IG), Steering heater switch on Below 1 V HINT: *1: When ambient temperature is 0 to 40°C (32 to 104°F). *2: The current to the heater turns ON/OFF depending on the temperature of the thermistor. As a result, it may take several minutes before a voltage value is output.

INSPECTION PROCEDURE

HINT

1. Inspect the fuses for circuits related to this system before performing the following inspection procedure.
2. The steering heater unit is built into the steering wheel assembly which cannot be disassembled. Therefore, when the steering heater unit has a malfunction, replace the steering wheel assembly.

Scheme 78

1. INSPECT STEERING WHEEL ASSEMBLY (THERMISTOR.HEATER.THERMOSTAT) Disconnect the B steering wheel controller connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition B-1 (TH1) - B-2 (TH2) 10 to 30°C (50 to 86°F) 8.132 to 18.43 kohms B-4 (SH1) - B-3 (SH2) 20°C (68°F) 1.89 to 2.25 ohms TEXT IN ILLUSTRATION *a Front view of wire harness connector (to Steering Wheel Control Assembly) NG --> See step 9 OK: Go to next step
2. INSPECT SPIRAL WITH SENSOR CABLE SUB-ASSEMBLY Check the connectors and cables of the spiral with sensor cable sub-assembly. OK There are no defects such as scratches, cracks, dents or damage on the connectors or cables. Disconnect the F97 and z14 spiral with sensor cable sub-assembly connectors. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition z14-1 (BTM) - F97-1 (BTM) Always Below 0.1 ohms z14-2 (ETM) - F97-3 (ETM) Always Below 0.1 ohms z14-3 (EHT) - F97-2 (EHT) Always Below 0.1 ohms z14-4 (BHT) - F97-4 (BHT) Always Below 0.1 ohms TEXT IN ILLUSTRATION *a Component without harness connected (Spiral with Sensor Cable Sub-assembly) - - NG --> See step 10 OK: Go to next step
3. CHECK STEERING HEATER SWITCH Disconnect the F100 steering heater switch connector. Measure the voltage according to the value(s) in the table below. HINT: As the circuit has a diode, perform the measurement in diode test mode, and do not mistake the polarity. Standard Voltage Tester Connection (Positive (+) tester probe - Negative (-) tester probe) Condition Specified Condition F100-1 (IG1) - F100-6 (IND) Always Below 1.25 V F100-5 (ECU) - F100-6 (IND) Steering heater switch is pushed Below 1.25 V Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition F100-1 (IG1) - F100-5 (ECU) Steering heater switch is pushed Below 1 ohms F100-1 (IG1) - F100-5 (ECU) Steering heater switch is not pushed 10 kohms or higher TEXT IN ILLUSTRATION *a Component without harness connected (Steering Heater Switch) NG --> See step 8 OK: Go to next step
4. CHECK HARNESS AND CONNECTOR (STEERING HEATER SWITCH - SPIRAL W/ SENSOR CABLE SUB-ASSEMBLY) Disconnect the F100 steering heater switch connector. Disconnect the F97 spiral with sensor cable sub-assembly connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition F100-6 (IND) - F97-1 (BTM) Always Below 1 ohms F100-5 (ECU) - F97-3 (ETM) Always Below 1 ohms F100-6 (IND) - Body ground Always 10 kohms or higher F100-5 (ECU) - Body ground Always 10 kohms or higher NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
5. CHECK HARNESS AND CONNECTOR (STEERING HEATER SWITCH POWER SOURCE) Disconnect the F100 steering heater switch connector. Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Condition Specified Condition F100-1 (IG1) - Body ground Engine switch on (IG) 11 to 14 V NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
6. CHECK HARNESS AND CONNECTOR (IG POWER SOURCE) Disconnect the F97 spiral with sensor cable sub-assembly connector. Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Condition Specified Condition F97-4 (BHT) - Body ground Engine switch on (IG) 11 to 14 V NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
7. CHECK HARNESS AND CONNECTOR (SPIRAL WITH SENSOR CABLE SUB-ASSEMBLY BODY GROUND) Disconnect the F97 spiral with sensor cable sub-assembly connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition F97-2 (EHT) - Body ground Always Below 1 ohms NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 11
8. REPLACE STEERING HEATER SWITCH. Refer to «REMOVAL [03/2012 - 07/2012]»(ref-602552-S35201625272014030500000)
9. REPLACE STEERING WHEEL ASSEMBLY. Refer to «REMOVAL [03/2012 - 07/2012]»(ref-602552-S35572137452014030500000)
10. REPLACE SPIRAL WITH SENSOR CABLE SUB-ASSEMBLY. Refer to «REMOVAL [03/2012 - 07/2012]»(ref-602553-S03151199422014030500000)
11. REPLACE STEERING WHEEL HEATER CONTROL ASSEMBLY. Refer to «REMOVAL [03/2012 - 07/2012]»(ref-602552-S03791180342014030500000)

HINT

1. Inspect the fuses for circuits related to this system before performing the following inspection procedure.
2. The steering heater unit is built into the steering wheel assembly which cannot be disassembled. Therefore, when the steering heater unit has a malfunction, replace the steering wheel assembly.