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Automatic A/c-Heater Systems: Diagnosis Lexus LS III

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 under SYSTEM TESTS.

SELF-DIAGNOSTICS

An Electronic Control Unit (ECU), located within A/C ECU, monitors system circuits and stores Diagnostic Trouble Codes (DTC) in memory if problems are detected. All codes, except DTC B1422/22 and B1423/23, are stored in memory. Codes B1422/22 or B1423/23 are current if they are displayed. To retrieve stored codes, see RETRIEVING DIAGNOSTIC TROUBLE CODES. Codes are displayed on driver side temperature display. (Схема №1)

CLEARING DIAGNOSTIC TROUBLE CODES

Remove A/C fuse located in driver side junction block. Wait at least 30 seconds before installing fuse. Retrieve diagnostic trouble codes. Verify only DTC B1400/00 is displayed. Diagnostic trouble codes can also be erased by pressing rear defrost switch while pressing front defrost switch. (Схема №1)