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Section 452 (Air Conditioning System - Diagnostics): Pre-Check

WARNING: This page is about a different car, the 2002 Toyota Prius. However, it is still accessible from the selected car via links, so may be relevant.
  1. Warning for A/C compressor lock:

    If compressor lock occurs during A/C operation, the A/C switch indicator on the A/C control assembly starts blinking.

    Fig 1: Reading Blinking A/C Control Assembly
    G01112322Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    When this occurs, check for compressor lock (DTC 22) using diagnosis trouble code check then proceed to inspect the circuit or the component.

    Compressor lock sensor circuit. See DTC 22: COMPRESSOR LOCK SENSOR CIRCUIT .

  2. List of operation methods:

    By operating each of the A/C control switches as shown in Fig 2, it is possible to enter the diagnosis check mode.

    Fig 2: Entering Diagnosis Check Mode Using A/C Control Switches
    G01112323Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  3. Indicator check:
    1. Within 5 seconds after turning the ignition switch on, press the A/C switch 3 times and turn the blower switch from OFF to AUTO.
      Fig 3: Identifying A/C & Blower Switches
      G01112324Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. NOTE:
      • After the indicator check is ended, the system enters the DTC begins automatically.
      • Operate the blower switch from AUTO to except AUTO position when desiring to cancel the check mode.
      Fig 4: Confirming Indicator Lights Interval
      G01112325Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    3. Check that all the indicators light up and go off at 1 second intervals 4 times in succession.
  4. DTC check (sensor check):
    1. Perform an indicator check. After the indicator check is completed, the system enters the DTC check mode automatically.
    2. NOTE: Fig 5 shows the blinking pattern associated with the DTC 12 and 23. If 2 or more DTCs (abnormalities) are indicated, the lowest number (code) is output first.
    3. Read the DTC as indicated by the number of blinks of the A/C indicator.
    4. Identify the problem using the chart of the DTC.
      Fig 5: Reading Malfunction Codes 12 & 23
      G01112326Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  5. Actuator check:
    1. Actuator check mode is started at the same time with DTC check mode.
    2. NOTE: To cancel the check mode, turn blower switch from AUTO to except AUTO.
      Fig 6: Identifying Blower Switch
      G01112327Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      Fig 7: Confirming Air Mix Damper Operation
      G01112328Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    3. Check visually on by hand that the air flow, amount of damper operating and operation of the compressor changes according to the set temperature of the A/C control panel, as shown in Fig 7.