Home/Lexus/RX/Lexus RX I (1997-2003)/Repair manual/Automatic HVAC System/Automatic A/c-Heater Systems: Diagnosis

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Wiring diagrams Section: Automatic HVAC System

Automatic A/c-Heater Systems - Wiring Diagrams

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Automatic A/c-Heater Systems: Diagnosis Lexus RX I

Automatic HVAC System ~152 words

SYMPTOM TESTS

Note. Perform SYMPTOM TESTS in order listed.

DTC NOT RECORDED, SET MODE IS CLEARED WHEN IGNITION SWITCH IS TURNED OFF

Check back-up power source circuit. See «BACK-UP POWER SOURCE CIRCUIT»(ref-98896-S22325533952001071300000) under SYSTEM TESTS.
Check A/C ECU ground circuit. See «A/C ECU GROUND CIRCUIT»(ref-98896-S01783194692001070900000) under SYSTEM TESTS.

SELF-DIAGNOSTICS

The A/C-heater control assembly monitors system circuits and stores Diagnostic Trouble Code (DTC) in memory if problems are detected. All DTCs are stored in memory except DTC B1422/22. Malfunction is current if DTC B1422/22 is displayed.

RETRIEVING DIAGNOSTIC TROUBLE CODES

Note. The following DTC retrieval procedure is performed using A/C-heater control assembly indicators. DTCs may also be retrieved using a scan tool. Follow scan tool manufacturer's instructions to retrieve DTCs.

CLEARING DIAGNOSTIC TROUBLE CODES

Remove ECU-B fuse from underhood junction block for at least 10 seconds to clear memory. After installing fuse, verify only normal DTC (DTC B1400/00) appears.