Section 404 (Air Conditioning System - Diagnosis): Pre-Check

WARNING: This page is about a different car, the 2004 Lexus ES 330. However, it is still accessible from the selected car via links, so may be relevant.

LIST OF OPERATION METHODS
By operating each of the A/C control switches as shown the diagram below, it is possible to enter the diagnosis check mode.

Fig 1: Diagnosis Check Mode Flow Chart
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INDICATOR CHECK
1. Turn the ignition switch ON while pressing the AUTO switch and R/F switch of A/C control assembly at the same time.
  
  Fig 2: Identifying AUTO & R/F Switches
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2. Check if the indicator light to be on and off at intervals 1 second for 4 times.
HINT:
- After the indicator check is completed, the system enters the DTC mode automatically.
- Press the "OFF" switch to cancel the check mode.
  
  Fig 3: Checking Indicator Light Pulse
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. DTC CHECK (SENSOR CHECK)
1. After the indicator check is completed, the system enters the DTC check mode automatically.
2. Read the code displayed on the panel. Refer to the *** of codes on DIAGNOSTIC TROUBLE CODE CHART when reading the code (Trouble code are output at the temperature display.)
3. If the slower display is desired, press the FRONT DEF switch and change it to stepped operation. Each time the FRONT DEF switch is pressed, the display changes by 1 step.
Fig 4: Checking DTC (Sensor)
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CLEARING DTC
1. Clear DTC by one of the following methods.
  1. Method 1: During sensor check, press the "FRONT DEF" switch and "REAR. DEF" switch at the same time.
  2. Method 2: Pull the ECU-B fuse in driver side J/B for 20 sec. or longer to clear the DTC memory.
Fig 5: Identifying Terminal ECU-B
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ACTUATOR CHECK
1. After entering the DTC check mode (Sensor Check Mode) press the R/F switch.
2. Since each damper, motor and relay automatically operates at 1 sec. intervals beginning in order from 10 in the temperature display, check the temperature and air flow visually and by hand.
  If the slower display is desired, press the DEF switch and change it to step operation. Each time the DEF switch is pressed, the display changes by 1 step.
HINT:
- Code are displayed in order from the smaller to the larger numbers.
- To cancel the check mode, press the OFF switch.
Fig 6: Checking Actuator
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Fig 7: Actuator Check Sequence Chart
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