Lexus IS250 · Service Manual BODY ELECTRICAL

Speaker Circuit

Circuit diagnosis

DESCRIPTION

The sound signal that has been amplified by the stereo component amplifier is sent to the speakers from the stereo component amplifier through this circuit.
If there is a short in this circuit, the stereo component amplifier detects it and stops output to the speakers.
Thus, sound cannot be heard from the speakers even if there is no malfunction in the stereo component amplifier or speakers.

WIRING DIAGRAM

E121251E02
E121252E02
E121253E01

INSPECTION PROCEDURE


1. CHECK HARNESS AND CONNECTOR

  1. E121254E05
    Disconnect the connectors shown in the illustration from the stereo component amplifier and speakers.

  1. with Front Center Speaker:Measure the resistance between the front stereo component speaker and the stereo component amplifier to check for an open circuit in the wire harness.

    Standard resistance:
    Below 1 Ω

  1. Measure the resistance between each of the front No. 3 speakers and the stereo component amplifier to check for an open circuit in the wire harness.

    Standard resistance:
    Below 1 Ω

  1. 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:
    Below 1 Ω

  1. without Front Center Speaker:Measure the resistance between each of the rear speakers and the stereo component amplifier to check for an open circuit in the wire harness.

    Standard resistance:
    Below 1 Ω

  1. with Front Center Speaker:Measure the resistance between each of the rear speakers and the stereo component amplifier to check for an open circuit in the wire harness.

    Standard resistance:
    Below 1 Ω

  1. without Front Center Speaker:Measure the resistance between each of the rear No. 3 speakers and the stereo component amplifier to check for an open circuit in the wire harness.

    Standard resistance:
    Below 1 Ω

  1. without Front Center Speaker: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:
    Below 1 Ω

  1. with Front Center Speaker:Measure the resistance between each of the rear No. 2 speakers and the rear speakers to check for an open circuit in the wire harness.

    Standard resistance:
    Below 1 Ω

  1. with Front Center Speaker:Measure the resistance between each of the rear stereo component speakers and the stereo component amplifier to check for an open circuit in the wire harness.

    Standard resistance:
    Below 1 Ω

  1. E121255E07
    Measure the resistance between each of the front No. 1 speakers and the stereo component amplifier to check for an open circuit in the wire harness.

    Standard resistance:
    Below 1 Ω

  1. Measure the resistance between the woofer box speaker and the stereo component amplifier to check for an open circuit in the wire harness.

    Standard resistance:
    Below 1 Ω

  1. Measure the resistance between each speaker and body ground to check for a short circuit in the wire harness.

    Standard resistance:
    10 kΩ or higher



 NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


2. INSPECT FRONT NO. 1 SPEAKER

  1. Resistance check.

    1. Measure the resistance between the terminals of the speaker.

      Standard resistance:
      with Front Center Speaker:
      6 to 10 Ω
      without Front Center Speaker:
      Approximately 4 Ω

      HINT:
      Perform the above inspection on both LH and RH sides.



 NG
REPLACE FRONT NO. 1 SPEAKER
OK


3. INSPECT FRONT NO. 2 SPEAKER

  1. Check that the malfunction disappears when another speaker in good condition is installed.

    Standard:
    Malfunction disappears.

    HINT:
    1. Connect all the connectors to the front No. 2 speakers.
    2. When there is a possibility that either the right or left front speaker is detective, inspect by interchanging the right one with the left one.
    3. Perform the above inspection on both LH and RH sides.



 OK
REPLACE FRONT NO. 2 SPEAKER
NG


4. INSPECT FRONT NO. 3 SPEAKER

  1. Check that the malfunction disappears when another speaker in good condition is installed.

    Standard:
    Malfunction disappears.

    HINT:
    1. Connect all the connectors to the front speakers.
    2. When there is a possibility that either the right or left front speaker is defective, inspect by interchanging the right one with the left one.
    3. Perform the above inspection on both LH and RH sides.



 OK
REPLACE FRONT NO. 3 SPEAKER
NG


5. INSPECT REAR NO. 2 SPEAKER

  1. Check that the malfunction disappears when another speaker in good condition is installed.

    Standard:
    Malfunction disappears.

    HINT:
    1. Connect all the connectors to the rear No. 2 speakers.
    2. When there is a possibility that either the right or left rear speaker is detective, inspect by interchanging the right one with the left one.
    3. Perform the above inspection on both LH and RH sides.



 OK
REPLACE REAR NO. 2 SPEAKER
NG


6. CONFIRM MODEL

Result:
Result
 Proceed to
with Front Center Speaker
 A
without Front Center Speaker
 B



B
Go to step 11
A


7. INSPECT REAR SPEAKER

  1. Check that the malfunction disappears when another speaker in good condition is installed.

    Standard:
    Malfunction disappears.

    HINT:
    1. Connect all the connectors to the rear speakers.
    2. When there is a possibility that either the right or left rear speaker is detective, inspect by interchanging the right one with the left one.
    3. Perform the above inspection on both LH and RH sides.



 OK
REPLACE REAR SPEAKER
NG


8. INSPECT REAR STEREO COMPONENT SPEAKER

  1. Check that the malfunction disappears when another speaker in good condition is installed.

OK:
Malfunction disappears.

HINT:
  1. Connect all the connectors to the rear stereo component speakers.
  2. When there is a possibility that either the right or left rear speaker is detective, inspect by interchanging the right one with the left one.
  3. Perform the above inspection on both LH and RH sides.



 OK
REPLACE REAR STEREO COMPONENT SPEAKER
NG


9. INSPECT FRONT STEREO COMPONENT SPEAKER

  1. Resistance check.

    1. Measure the resistance between the terminals of the speaker.

      Standard resistance:
      7 to 9 Ω



 NG
REPLACE FRONT STEREO COMPONENT SPEAKER
OK


10. INSPECT WOOFER BOX SPEAKER

  1. E120044
    Resistance check.

    1. Measure the resistance according to the value(s) in the table below.

      NOTICE:
      The speaker should not be removed for checking.

      Standard resistance:
      Tester connection
      		 Condition
      		 Specified condition
      3 - 4
      		 Always
      		 7 to 8.6 Ω



NG
REPLACE WOOFER BOX SPEAKER
OK

PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE

11. INSPECT REAR NO. 3 SPEAKER

  1. Check that the malfunction disappears when another speaker in good condition is installed.

    Standard:
    Malfunction disappears.

    HINT:
    1. Connect all the connectors to the rear No. 3 speakers.
    2. When there is a possibility that either the right or left rear No. 3 speaker is detective, inspect by interchanging the right one with the left one.
    3. Perform the above inspection of both LH or RH sides.



 OK
REPLACE REAR NO. 3 SPEAKER
NG


12. INSPECT REAR SPEAKER

  1. Resistance check.

    1. Measure the resistance according to the value(s) in the table below.

      Standard resistance:
      Approximately 4 Ω

      HINT:
      Perform the above inspection on both LH and RH sides.



 NG
REPLACE REAR SPEAKER
OK


13. INSPECT WOOFER BOX SPEAKER

  1. E120044
    Resistance check.

    1. Measure the resistance according to the value(s) in the table below.

      NOTICE:
      The speaker should not be removed for checking.

      Standard resistance:
      Tester connection
      		 Condition
      		 Specified condition
      1 - 3
      		 Always
      		 Approximately 2 Ω
      2 - 4
      		 Always
      		 Approximately 2 Ω



NG
REPLACE WOOFER BOX SPEAKER
OK

PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE


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