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

PRECAUTION [03/2012 - 07/2012]

1. PRECAUTION FOR DISCONNECTING THE BATTERY CABLE NOTE: When disconnecting the battery negative (-) cable, initialize the following system(s) after the cable is reconnected: System Name See Procedure Parking Assist Monitor System Refer to «INITIALIZATION [03/2012 - 07/2012]»(ref-602551-S24591545042014030500000) Back Door Closer System Power Back Door System
2. HANDLING PRECAUTIONS FOR SRS AIRBAG SYSTEM This vehicle is equipped with a Supplemental Restraint System (SRS). Failure to carry out service operations in the correct sequence could cause the SRS to unexpectedly deploy during servicing. This may cause a serious accident. Before servicing (including inspection, replacement, removal and installation of parts), be sure to read the precautionary notices for Supplemental Restraint System. Refer to «PRECAUTION [03/2012 - 07/2012]»(ref-602724-S22259792752014030500000) .

PRECAUTION [07/2012 - ]

1. PRECAUTION FOR DISCONNECTING THE BATTERY CABLE NOTE: When disconnecting the battery negative (-) cable, initialize the following system(s) after the cable is reconnected: System Name See Procedure Parking Assist Monitor System Refer to «INITIALIZATION [07/2012 - ]»(ref-602551-S38908041872014030500000) Back Door Closer System Power Back Door System
2. HANDLING PRECAUTIONS FOR SRS AIRBAG SYSTEM This vehicle is equipped with a Supplemental Restraint System (SRS). Failure to carry out service operations in the correct sequence could cause the SRS to unexpectedly deploy during servicing. This may cause a serious accident. Before servicing (including inspection, replacement, removal and installation of parts), be sure to read the precautionary notices for Supplemental Restraint System. Refer to «PRECAUTION [07/2012 - ]»(ref-602724-S13282392072014030500000) .

Scheme 79

Scheme 80

Scheme 81

1. SYSTEM DIAGRAM

Scheme 82

Scheme 83

1. HEATED STEERING WHEEL SYSTEM The heated steering wheel system heats the steering wheel when the steering heater switch is operated. The heated steering wheel system uses a thermistor inside of the steering wheel to detect the heater temperature and maintain the set temperature. The heated steering wheel timer function turns off the heater after a predetermined period of time.
2. HEATER CONTROLLER SYSTEM Operation description When the engine switch is on (IG), pressing the steering heater switch illuminates the LED and current is output from the steering controller to the heater of the heated steering wheel system. Pressing the steering heater switch again turns off the LED and stops the current from being output. A thermostat is installed in the steering wheel as a safety mechanism. The steering heater switch LED will blink at 0.3 second intervals when either of the following occurs: 1) an open or short in the steering wheel thermistor continues for 2 seconds or more; or 2) the steering heater switch is pressed continuously for 10 seconds or more. If the normal condition is restored for 2 seconds or more, the previous operation before the malfunction occurred continues. However, regardless of if a malfunction is detected and the malfunction operation is occurring, and regardless of if the normal condition is restored and the system is operating normally, the timer will turn off the heater 30 minutes after the switch was first turned on. Signal input / output description Signal Signal Name Function Signal Type Input Thermistor input Input of voltage corresponding to heater temperature Analog input Input Temperature setting input Input of voltage corresponding to temperature setting Analog input Input Operating switch input Input of power circuit latch operation estimate signal LOW / HI input Output LED output Output of LED LOW / HI input Output Heater output Output of heater LOW / HI input Output Latch output Power circuit maintenance LOW / HI input Safety function Content Operation When thermistor trouble is detected Heater off When overheating (175°C (347°F)) of controller is detected Heater off When load short current (50 A or more) is detected Heater off When undervoltage (4.5 V) is detected Heater off OFF timer (30 min.) After preset time of timer passes, heater off Reverse voltage protection Protection circuit operates

FAIL-SAFE CHART [03/2012 - ]

1. MALFUNCTION DETECTION Operation when malfunction is detected Content Operation When thermistor trouble is detected Heater off When overheating (175°C (347°F)) of controller is detected Heater off When load short current (50 A or more) is detected Heater off When undervoltage (4.5 V) is detected Heater off OFF timer (30 min.) After preset time of timer passes, heater off Reverse voltage protection Protection circuit operates Malfunction detection conditions When an open or short in the steering wheel thermistor continues for 2 seconds or more. When the steering heater switch is pressed continuously for 10 seconds or more. Malfunction display The LED of the steering heater switch blinks at 0.3 second intervals. Restore condition If the normal condition is restored for 2 seconds or more, the previous operation before the malfunction occurred continues. However, regardless of if a malfunction is detected and the malfunction operation is occurring, and regardless of if the normal condition is restored and the system is operating normally, the timer will turn off the heater 30 minutes after the switch was first turned on.

PROCEDURE

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 [07/2012 - ]»(ref-602552-S31046964892014030500000)
9. REPLACE STEERING WHEEL ASSEMBLY. Refer to «REMOVAL [07/2012 - ]»(ref-602552-S05692799392014030500000)
10. REPLACE SPIRAL WITH SENSOR CABLE SUB-ASSEMBLY. Refer to «REMOVAL [07/2012 - ]»(ref-602553-S33625378332014030500000)
11. REPLACE STEERING WHEEL HEATER CONTROL ASSEMBLY. Refer to «REMOVAL [07/2012 - ]»(ref-602552-S23057181972014030500000)