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Inspection Procedure

WARNING: This page is about a different car, the 2005 Toyota Sienna. However, it is still accessible from the selected car via links, so may be relevant.
  1. INSPECT STEERING PAD SWITCH ASSY (AU1, AU2, EAU) 
    Fig 1: Inspecting Steering Pad Switch Assy (AU1, AU2, EAU)
    G02630148Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. Remove the steering pad switch assy.
    2. Check continuity between terminals at each condition, as shown in TERMINALS CONTINUITY  .

      Standard: 

    STEERING PAD SWITCH ASSY (AU1, AU2, EAU) CONTINUITY

    Tester connection Condition Specified condition
    AU1 - EAU Do not switch position Approx. 100 kΩ
    AU1 - EAU SEEK+ switch: push 0 Ω
    AU1 - EAU SEEK- switch: push Approx. 0.3 kΩ
    AU1 - EAU VOL+ switch: push Approx. 1 kΩ
    AU1 - EAU VOL- switch: push Approx. 3.2 kΩ
    AU1 - EAU Do not switch position Approx. 100 kΩ
    AU1 - EAU MODE switch: push 0 Ω
    1. NG: REPLACE STEERING PAD SWITCH ASSY 
    2. OK: GO TO NEXT STEP 
  2. CHECK HARNESS AND CONNECTOR (STEERING PAD SWITCH LH - RADIO RECEIVER ASSY) 
    1. Disconnect the connectors from the steering pad switch LH and radio receiver assy.
      1. Check continuity between terminals at each condition, as shown in STEERING PAD SWITCH LH - RADIO RECEIVER ASSY CONTINUITY  .

        Standard: 

        STEERING PAD SWITCH LH - RADIO RECEIVER ASSY CONTINUITY

        Tester connection Specified condition
        SW1--AU1 Continuity
        SW2-AU2 Continuity
        GND - EAU Continuity
      2. Check for a short between terminals at each condition, as shown in STEERING PAD SWITCH LH - RADIO RECEIVER ASSY SHORT  .

        Standard: 

      STEERING PAD SWITCH LH - RADIO RECEIVER ASSY SHORT

      Tester connection Specified condition
      SW1-Body ground No continuity
      SW2-Body ground No continuity
      GND-Body ground No continuity
    Fig 2: Checking Harness & Connector (Steering Pad Switch LH - Radio Receiver Assy)
    G02630149Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. NG: REPAIR OR REPLACE HARNESS OR CONNECTOR (See  ELECTRONIC CIRCUIT INSPECTION PROCEDURE  ) 
    2. OK: REPLACE RADIO RECEIVER ASSY