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Home >> Lexus >> 2012 >> IS F >> Repair and Diagnosis (Single Page) >> Accessories & Equipment >> Entertainment Systems >> Audio / Video System (W/O Navigation Display) (W/O Multi-Display) (Diagnostics & Symptom Tests) >> AUDIO AND VISUAL SYSTEM (w/o Navigation System without Multi-display) >> DTC 74-40: Short in Speaker Circuit >> Procedure

DTC 74-40: Short in Speaker Circuit: Procedure

  1. INSPECT STEREO COMPONENT AMPLIFIER ASSEMBLY 
    1. Disconnect the stereo component amplifier assembly connectors P44 and P28.
    2. Clear the DTCs and recheck for DTCs.
    3. Check if DTC 74-40 is output.

      OK

      DTC 74-40 is not output.

    NG → See step   15 

    OK: Go to next step 

  2. CHECK OPERATION 
    1. Reconnect the stereo component amplifier assembly connector P28.
    2. Check if DTC 74-40 is output.

      OK

      DTC 74-40 is not output.

    NG → See step   9 

    OK: Go to next step 

  3. CHECK HARNESS AND CONNECTOR 
    1. Disconnect P44 stereo component amplifier assembly connector.
    2. Disconnect J114 DCM (telematics transceiver) connector.*1
      • *1: w/ Manual (SOS) Switch
    3. Disconnect L1, M13, N4, N6, O4, O6, N3 and O3 speaker connectors.
    4. Measure the resistance between the stereo component amplifier assembly and body ground to check for a short circuit in the wire harness.

      Standard Resistance

      Tester Connection Condition Specified Condition
      P44-10 (WFR+) - Body ground Always 10 kΩ or higher
      P44-9 (WFR-) - Body ground Always 10 kΩ or higher
      P44-3 (WFL+) - Body ground Always 10 kΩ or higher
      P44-8 (WFL-) - Body ground Always 10 kΩ or higher
      P44-2 (MR+) - Body ground Always 10 kΩ or higher
      P44-7 (MR-) - Body ground Always 10 kΩ or higher
      P44-1 (ML+) - Body ground Always 10 kΩ or higher
      P44-6 (ML-) - Body ground Always 10 kΩ or higher
      P44-5 (RR+) - Body ground Always 10 kΩ or higher
      P44-12 (RR-) - Body ground Always 10 kΩ or higher
      P44-4 (RL+) - Body ground Always 10 kΩ or higher
      P44-11 (RL-) - Body ground Always 10 kΩ or higher
    5. w/ Manual (SOS) Switch:

      Measure the resistance between the front No. 1 speaker RH and body ground to check for a short circuit in the wire harness.

      Standard Resistance

      Tester Connection Condition Specified Condition
      L1-1 - Body ground Always 10 kΩ or higher
      L1-2 - Body ground Always 10 kΩ or higher
    6. Measure the resistance between the rear No. 2 speakers and body ground to check for a short circuit in the wire harness.

      Standard Resistance

      Tester Connection Condition Specified Condition
      N6-1 - Body ground Always 10 kΩ or higher
      N6-2 - Body ground Always 10 kΩ or higher
      O6-1 - Body ground Always 10 kΩ or higher
      O6-2 - Body ground Always 10 kΩ or higher
    7. Measure the resistance between the front No. 1 speaker LH and the stereo component amplifier assembly to check for an open circuit in the wire harness.

      Standard Resistance

      Tester Connection Condition Specified Condition
      P44-3 (WFL+) - M13-1 Always Below 1 Ω
      P44-8 (WFL-) - M13-2 Always Below 1 Ω
    8. w/o Manual (SOS) Switch:

      Measure the resistance between the front No. 1 speaker RH and the stereo component amplifier assembly to check for an open circuit in the wire harness.

      Standard Resistance

      Tester Connection Condition Specified Condition
      P44-10 (WFR+) - L1-1 Always Below 1 Ω
      P44-9 (WFR-) - L1-2 Always Below 1 Ω
    9. w/ Manual (SOS) Switch:

      Measure the resistance between the stereo component amplifier assembly and the DCM (telematics transceiver) to check for an open circuit in the wire harness.

      Standard Resistance

      Tester Connection Condition Specified Condition
      P44-10 (WFR+) - J114-2 (SPI+) Always Below 1 Ω
      P44-9 (WFR-) - J114-3 (SPI-) Always Below 1 Ω
    10. w/ Manual (SOS) Switch:

      Measure the resistance between the front No. 1 speaker RH and the DCM (telematics transceiver) to check for an open circuit in the wire harness.

      Standard Resistance

      Tester Connection Condition Specified Condition
      J114-5 (SPO+) -L1-1 Always Below 1 Ω
      J114-6 (SPO-) - L1-2 Always Below 1 Ω
    11. Measure the resistance between each of the rear speakers and the stereo component amplifier assembly to check for an open circuit in the wire harness.

      Standard Resistance

      Tester Connection Condition Specified Condition
      P44-5 (RR+) - N3-1 Always Below 1 Ω
      P44-12 (RR-) - N3-2 Always Below 1 Ω
      P44-4 (RL+) - O3-1 Always Below 1 Ω
      P44-11 (RL-) - O3-2 Always Below 1 Ω
    12. Measure the resistance between each of the rear No. 3 speakers and the stereo component amplifier assembly to check for an open circuit in the wire harness.

      Standard Resistance

      Tester Connection Condition Specified Condition
      P44-2 (MR+) - N4-1 (+) Always Below 1 Ω
      P44-7 (MR-) - N4-3 (-) Always Below 1 Ω
      P44-1 (ML+) - O4-1 (+) Always Below 1 Ω
      P44-6 (ML-) - O4-3 (-) Always Below 1 Ω
    13. Measure the resistance between each of the rear No. 2 speakers and the rear No. 3 speakers to check for an open circuit in the wire harness.

      Standard Resistance

      Tester Connection Condition Specified Condition
      N4-2 (+TW) - N6-1 Always Below 1 Ω
      N4-4 (-TW) - N6-2 Always Below 1 Ω
      O4-2 (+TW) - O6-1 Always Below 1 Ω
      O4-4 (-TW) - O6-2 Always Below 1 Ω

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  4. INSPECT FRONT NO. 1 SPEAKER 
    1. Resistance check
      Fig 1: View Of Front No. 1 Speaker Connector
      GTY281899Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      1. Measure the resistance according to the value(s) in the table below.

        Standard Resistance

        Tester Connection Condition Specified Condition
        L1-1 - L1-2 Always 3.2 to 4.8 Ω
        M13-1 - M13-2 Always 3.2 to 4.8 Ω
        TEXT IN ILLUSTRATION

        *1 Component without harness connected
        (Front No. 1 Speaker)

    NG → See step   13 

    OK: Go to next step 

  5. INSPECT REAR SPEAKER 
    1. Resistance check
      Fig 2: View Of Rear Speaker Connector Terminals
      GTY260157Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      1. Measure the resistance according to the value(s) in the table below.

        Standard Resistance

        Tester Connection Condition Specified Condition
        N3-1 - N3-2 Always 3.2 to 4.8 Ω
        O3-1 - O3-2 Always 3.2 to 4.8 Ω
        TEXT IN ILLUSTRATION

        *1 Component without harness connected
        (Rear Speaker)

    NG → See step   14 

    OK: Go to next step 

  6. INSPECT REAR NO. 2 SPEAKER 
    1. Resistance check
      Fig 3: View Of Rear No. 2 Speaker Connector And Terminals
      GTY262870Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      1. Measure the resistance according to the value(s) in the table below.

        Standard Resistance

        Tester Connection Condition Specified Condition
        N6-1 - N6-2 Always 3.2 to 4.8 Ω
        O6-1 - O6-2 Always 3.2 to 4.8 Ω
        TEXT IN ILLUSTRATION

        *1 Component without harness connected
        (Rear No. 2 Speaker)

    NG → See step   18 

    OK: Go to next step 

  7. INSPECT REAR NO. 3 SPEAKER 
    1. Resistance check
      Fig 4: View Of Rear No. 3 Speaker Connector And Terminals
      GTY261415Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      1. Measure the resistance according to the value(s) in the table below.

        Standard Resistance

        Tester Connection Condition Specified Condition
        N4-1 (+) - N4-3 (-) Always 3.2 to 4.8 Ω
        N4-1 (+) - N4-2 (+TW) Always 10 kΩ or higher
        N4-3 (-) - N4-4 (-TW) Always Below 1 Ω
        O4-1 (+) - O4-3 (-) Always 3.2 to 4.8 Ω
        O4-1 (+) - O4-2 (+TW) Always 10 kΩ or higher
        O4-3 (-) - O4-4 (-TW) Always Below 1 Ω
        TEXT IN ILLUSTRATION

        *1 Component without harness connected
        (Rear No. 3 Speaker)
    2. Proceed to the next step based on the inspection result.

      Result

      Condition Proceed to
      OK (w/ Manual (SOS) Switch) A
      OK (w/o Manual (SOS) Switch) B
      NG C

    B → See step   15 

    C → See step   21 

    A: Go to next step 

  8. INSPECT DCM (TELEMATICS TRANSCEIVER) 
    1. Resistance check
      Fig 5: Identifying Telematics Transceiver J114 Connector Terminals
      GTY280798Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      1. Measure the resistance according to the value(s) in the table below.

        Standard Resistance

        Tester Connection Condition Specified Condition
        J114-2 (SPI+) - J114-5 (SPO+) Always Below 1 Ω
        J114-3 (SPI-) - J114-6 (SPO-) Always Below 1 Ω
        J114-2 (SPI+) - J114-3 (SPI-) Always 10 kΩ or higher
        J114-5 (SPO+) - J114-6 (SPO-) Always 10 kΩ or higher
        J114-3 (SPI-) - Body ground Always 10 kΩ or higher
        J114-2 (SPI+) - Body ground Always 10 kΩ or higher
        TEXT IN ILLUSTRATION

        *1 Component without harness connected
        (DCM (Telematics Transceiver))

    NG → See step   17 

    OK → See step   15 

  9. CHECK HARNESS AND CONNECTOR 
    1. Disconnect the stereo component amplifier assembly connector P28 and speaker connectors M12, M4, L5, L2 and P21.
    2. Measure the resistance between the stereo component amplifier assembly and body ground to check for a short circuit in the wire harness.

      Standard Resistance

      Tester Connection Condition Specified Condition
      P28-4 (FR+) - Body ground Always 10 kΩ or higher
      P28-10 (FR-) - Body ground Always 10 kΩ or higher
      P28-3 (FL+) - Body ground Always 10 kΩ or higher
      P28-9 (FL-) - Body ground Always 10 kΩ or higher
      P28-1 (WF1+) - Body ground Always 10 kΩ or higher
      P28-5 (WF1-) - Body ground Always 10 kΩ or higher
      P28-2 (WF2+) - Body ground Always 10 kΩ or higher
      P28-6 (WF2-) - Body ground Always 10 kΩ or higher
    3. Measure the resistance between each of the front No. 2 speakers and body ground to check for a short circuit in the wire harness.

      Standard Resistance

      Tester Connection Condition Specified Condition
      L5-1 - Body ground Always 10 kΩ or higher
      L5-2 - Body ground Always 10 kΩ or higher
      M12-1 - Body ground Always 10 kΩ or higher
      M12-2 - Body ground Always 10 kΩ or higher
    4. Measure the resistance between each of the front No. 3 speakers and the stereo component amplifier assembly to check for an open circuit in the wire harness.

      Standard Resistance

      Tester Connection Condition Specified Condition
      P28-4 (FR+) - L2-1 (TWR+) Always Below 1 Ω
      P28-10 (FR-) - L2-3 (TWR-) Always Below 1 Ω
      P28-3 (FL+) - M4-1 (TWL+) Always Below 1 Ω
      P28-9 (FL-) - M4-3 (TWL-) Always Below 1 Ω
    5. Measure the resistance between each of the front No. 2 speakers and the front No. 3 speakers to check for an open circuit in the wire harness.

      Standard Resistance

      Tester Connection Condition Specified Condition
      L2-2 (+) - L5-1 Always Below 1 Ω
      L2-4 (-) - L5-2 Always Below 1 Ω
      M4-2 (+) - M12-1 Always Below 1 Ω
      M4-4 (-) - M12-2 Always Below 1 Ω
    6. Measure the resistance between the stereo component speaker and the stereo component amplifier assembly to check for an open circuit in the wire harness.

      Standard Resistance

      Tester Connection Condition Specified Condition
      P28-1 (WF1+) - P21-1 (WF1+) Always Below 1 Ω
      P28-5 (WF1-) - P21-3 (WF1-) Always Below 1 Ω
      P28-2 (WF2+) - P21-2 (WF2+) Always Below 1 Ω
      P28-6 (WF2-) - P21-4 (WF2-) Always Below 1 Ω

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  10. INSPECT FRONT NO. 2 SPEAKER 
    1. Resistance check
      Fig 6: View Of Front No. 2 Speaker Connector And Terminals
      GTY258709Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      1. Measure the resistance according to the value(s) in the table below.

        Standard Resistance

        Tester Connection Condition Specified Condition
        L5-1 - L5-2 Always 3.2 to 4.8 Ω
        M12-1 - M12-2 Always 3.2 to 4.8 Ω
        TEXT IN ILLUSTRATION

        *1 Component without harness connected
        (Front No. 2 Speaker)

    NG → See step   16 

    OK: Go to next step 

  11. INSPECT FRONT NO. 3 SPEAKER 
    1. Resistance check
      Fig 7: Inspecting Front No. 3 Speaker
      GTY267941Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      1. Measure the resistance according to the value(s) in the table below.

        Standard Resistance

        Tester Connection Condition Specified Condition
        L2-1 (TWR+) - L2-3 (TWR-) Always 3.2 to 4.8 Ω
        L2-1 (TWR+) - L2-2 (+) Always 10 kΩ or higher
        L2-3 (TWR-) - L2-4 (-) Always Below 1 Ω
        M4-1 (TWL+) - M4-3 (TWL-) Always 3.2 to 4.8 Ω
        M4-1 (TWL+) - M4-2 (+) Always 10 kΩ or higher
        M4-3 (TWL-) - M4-4 (-) Always Below 1 Ω
        TEXT IN ILLUSTRATION

        *A for RH
        *B for LH
        *1 Component without harness connected
        (Front No. 3 Speaker)

    NG → See step   20 

    OK: Go to next step 

  12. INSPECT STEREO COMPONENT SPEAKER 
    1. Resistance check
      Fig 8: Identifying Stereo Component Speaker Connector Terminals
      GTY269265Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      1. Measure the resistance according to the value(s) in the table below.

        Standard Resistance

        Tester Connection Condition Specified Condition
        P21-1 (WF1+) - P21-3 (WF1-) Always 1.6 to 2.4 Ω
        P21-2 (WF2+) - P21-4 (WF2-) Always 1.6 to 2.4 Ω
        TEXT IN ILLUSTRATION

        *1 Component without harness connected
        (Stereo Component Speaker)

    NG → See step   19 

    OK → See step   15 

  13. REPLACE FRONT NO. 1 SPEAKER. Refer to  REMOVAL 
  14. REPLACE REAR SPEAKER. Refer to  REMOVAL 
  15. REPLACE STEREO COMPONENT AMPLIFIER ASSEMBLY. Refer to  REMOVAL 
  16. REPLACE FRONT NO. 2 SPEAKER. Refer to  REMOVAL 
  17. REPLACE DCM (TELEMATICS TRANSCEIVER). Refer to  REMOVAL 
  18. REPLACE REAR NO. 2 SPEAKER. Refer to  REMOVAL 
  19. REPLACE STEREO COMPONENT SPEAKER. Refer to  REMOVAL 
  20. REPLACE FRONT NO. 3 SPEAKER. Refer to  REMOVAL 
  21. REPLACE REAR NO. 3 SPEAKER. Refer to  REMOVAL 
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