Climate Control Seat (Diagnostics): Diagnosis Lexus RX III

HOW TO PROCEED WITH TROUBLESHOOTING (TO 08/2009)

HINT

1. Use this procedure to troubleshoot the climate control seat system.
2. The Techstream should be used in step 4.

1. VEHICLE BROUGHT TO WORKSHOP NEXT: Go to next step
2. CUSTOMER PROBLEM ANALYSIS CHECK AND SYMPTOM CHECK NEXT: Go to next step
3. PROBLEM SYMPTOMS TABLE HINT: NEXT: Go to next step
4. OVERALL ANALYSIS AND TROUBLESHOOTING Circuit inspection Terminal of ECU HINT: NEXT: Go to next step
5. ADJUST, REPAIR OR REPLACE NEXT --> END

HOW TO PROCEED WITH TROUBLESHOOTING (FROM 08/2009)

HINT

1. Use this procedure to troubleshoot the climate control seat system.
2. The Techstream should be used in step 4.

1. VEHICLE BROUGHT TO WORKSHOP NEXT: Go to next step
2. CUSTOMER PROBLEM ANALYSIS CHECK AND SYMPTOM CHECK NEXT: Go to next step
3. PROBLEM SYMPTOMS TABLE HINT: NEXT: Go to next step
4. OVERALL ANALYSIS AND TROUBLESHOOTING Circuit inspection Terminal of ECU HINT: NEXT: Go to next step
5. ADJUST, REPAIR OR REPLACE NEXT --> END

PROBLEM SYMPTOMS TABLE (TO 08/2009)

HINT

1. 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 symptoms by checking the suspected areas in the order they are "Suspected Area" column of the table. Check each symptom by checking the suspected areas in the order they are listed. Replace parts as necessary.

CLIMATE CONTROL SYSTEM

PROBLEM SYMPTOMS TABLE (FROM 08/2009)

HINT

1. 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 symptoms by checking the suspected areas in the order they are "Suspected Area" column of the table. Check each symptom by checking the suspected areas in the order they are listed. Replace parts as necessary.

CLIMATE CONTROL SYSTEM

Scheme 120

Scheme 121

1. A/C AMPLIFIER ASSEMBLY Disconnect the F50 connector. Measure the voltage and resistance according to the value(s) in the table below. HINT: Measure the values on the wire harness side with the connector disconnected. Tester Connection Wiring Color Terminal Description Condition Specified Condition F50-21 (B) - Body ground G - Body ground A/C amplifier power supply Always 11 to 14 V F50-21 (IG+) - Body ground P - Body ground A/C amplifier power supply Engine switch on (IG) 11 to 14 V F50-14 (GND) - Body ground W-B - Body ground A/C amplifier ground Always Below 1 ohms If the result is not as specified, there may be a malfunction on the wire harness side. Reconnect the F50 connector. Measure the voltage and resistance according to the value(s) in the table below. Tester Connection Wiring Color Terminal Description Condition Specified Condition F51-6 (SG-5) - Body ground L - Body ground Seat heater switch volume ground Always Below 1 ohms F51-8 (S5-2) - Body ground BR - Body ground Seat heater switch volume power source Engine switch on (IG) 4.5 to 5.5 V F51-15 (SVDS) - Body ground SB - Body ground Seat heater switch volume signal Seat heater switch volume between 0 and 3 0 to 5 V F51-16 (SVPS) - Body ground LG - Body ground Seat heater switch volume signal Seat heater switch volume between 0 and 3 0 to 5 V F51-10 (SVPB) - Body ground G - Body ground Climate control blower control signal Engine switch on (IG), climate control switch on. Pulse generation (See waveform) F51-9 (SVDB) - Body ground GR - Body ground Climate control blower control signal Engine switch on (IG), climate control switch on. Pulse generation (See waveform) If the result is not as specified, the ECU may have a malfunction. Waveform (Reference): Using an oscilloscope: Tester Connection F51-10 (SVPB) - Body ground F51-9 (SVDB) - Body ground Tool setting 2 V/DIV., 500 μsec/DIV. Vehicle condition Turn the engine switch on (IG)

ON-VEHICLE INSPECTION

1. CHECK SEAT CLIMATE CONTROL BLOWER LH Turn the engine switch on (IG). Set the seat heater switch blower side volume to level 3 (maximum). Check that the fan motor turns smoothly.
2. CHECK SEAT CUSHION CLIMATE CONTROL BLOWER ASSEMBLY LH Turn the engine switch on (IG). Set the seat heater switch blower side volume to level 3 (maximum). Check that the fan motor turns smoothly.
3. CHECK SEATBACK CLIMATE CONTROL BLOWER RH Turn the engine switch on (IG). Set the seat heater switch blower side volume to level 3 (maximum). Check that the fan motor turns smoothly.
4. CHECK SEAT CUSHION CLIMATE CONTROL BLOWER ASSEMBLY RH Turn the engine switch on (IG). Set the seat heater switch blower side volume to level 3 (maximum). Check that the fan motor turns smoothly.