Section 351 (Automatic HVAC Systems): Pre-Check

WARNING: This page is about a different car, the 2002 Toyota 4Runner. 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 in the diagram below, it is possible to enter the diagnosis check mode.

Fig 1: Operating A/C Control Switches To Determine Diagnosis
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INDICATOR CHECK
1. Turn the ignition switch to ON while pressing the air conditioning control AUTO switch and R/F switch simultaneously.
  
  Fig 2: Pressing A/C Control AUTO Switch & R/F Switch Simultaneously
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2. Check that all the indicators light up and go off at one second intervals 4 times in succession.
HINT:
- After the indicator check is ended, the system enters the DTC begins automatically.
- Press the OFF switch when desiring to cancel the check mode.
Fig 3: Checking Indicator Lights 4 Times In Succession
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DTC CHECK (SENSOR CHECK)
1. Perform an indicator check. After the indicator check is completed, the system enters the DTC check mode automatically.
2. Read the displayed on the panel. Refer to DIAGNOSTIC TROUBLE CODE CHART when reading the DTCs. (DTCs are output at the temperature display).
  
  Fig 4: Reading Code Display On Panel
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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 one step.
  
  Fig 5: Pressing Front DEF Switch
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CLEARING DTC
1. Pull out the ECU-B fuse in No. 1 J/B for 10 seconds, or longer to clear the DTC memory.
2. After reinserting the fuse, check that the normal code is output.
Fig 6: Clearing DTC Memory By Removing ECU-B Fuse
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ACTUATOR CHECK
1. After entering the DTC check mode (Sensor Check Mode) press the R/F switch.
  
  Fig 7: Pressing A/C Switches After Entering DTC Check Mode
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2. Since each damper, motor and relay automatically operates at one second intervals beginning in order from 10 in the temperature display, check the temperature and air flow visually and by hand.
  If a slower display is desired, press the FRONT DEF switch and change it to a stepped operation. Each time the FRONT DEF switch is pressed, the display changes by one step.
HINT:
- Code are displayed in order from the smaller to the larger numbers.
- To cancel the check mode, press the Off switch.
Fig 8: Determining Actuator Check Display Codes & Conditions
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