Vehicle Speed Signal Circuit between Stereo Component Amplifier and Combination Meter: Procedure

1. Check the output waveform.
   Fig 1: Identifying L27 Connector

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   1. Remove the combination meter assembly with the connector(s) still connected.
   2. Connect an oscilloscope to terminal L27-7 (+S) and body ground.
   3. Turn the power switch on (IG).
   4. Turn a wheel slowly.
   5. Check the signal waveform according to the condition(s) in the table below.

      Item	Condition
      Measurement terminal	L27-7 (+S) - Body ground
      Tool setting	5 V/DIV., 20 ms./DIV.
      Vehicle condition	Wheel being rotated

      OK

      The waveform is similar to that shown in the illustration.

      HINT: 

      When the system is functioning normally, one wheel revolution generates 4 pulses. As the vehicle speed increases, the width indicated by (A) in the illustration narrows.

   TEXT IN ILLUSTRATION
   
   

   *1	Component with harness connected (Combination Meter Assembly)

NG → See step   10 

OK: Go to next step 

1. Disconnect the L31 stereo component amplifier assembly connector.
   Fig 2: Identifying L31 Stereo Component Amplifier Assembly Connector

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2. Disconnect the L27 combination meter assembly connector.
   Fig 3: Identifying L27 Combination Meter Assembly Connector

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

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   L31-11 (SPD) - L27-7 (+S)	Always	Below 1 Ω

   TEXT IN ILLUSTRATION
   
   

   *1	Front view of wire harness connector (to Stereo Component Amplifier Assembly)
   *2	Front view of wire harness connector (to Combination Meter Assembly)

NG → See step   4 

OK → See step   3 

1. Disconnect the L31 stereo component amplifier assembly connector.
   Fig 4: Identifying L31 Stereo Component Amplifier Assembly Connector

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2. Disconnect the 4A No. 4 junction block connector.
   Fig 5: Identifying 4A No. 4 Junction Block Connector

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

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   L31-11 (SPD) - 4A-69	Always	Below 1 Ω

   TEXT IN ILLUSTRATION
   
   

   *1	Front view of wire harness connector (to Stereo Component Amplifier Assembly)
   *2	Front view of wire harness connector (to No. 4 Junction Block)

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR (STEREO COMPONENT AMPLIFIER - NO. 4 JUNCTION CONNECTOR) 

OK: Go to next step 

1. Disconnect the 4A No. 4 junction block connector.
   Fig 6: Identifying 4A No. 4 Junction Block Connector

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2. Disconnect the 3B No. 3 junction block connector.
   Fig 7: Identifying 3B No. 3 Junction Block Connector

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

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   4A-21 - 3B-85	Always	Below 1 Ω

   TEXT IN ILLUSTRATION
   
   

   *1

   Front view of wire harness connector (to No. 4 Junction Block)

   *2

   Front view of wire harness connector (to No. 3 Junction Block)

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR (NO. 4 JUNCTION CONNECTOR - NO. 3 JUNCTION CONNECTOR) 

OK: Go to next step 

1. Disconnect the 3A No. 3 junction block connector.
   Fig 8: Identifying 3A No. 3 Junction Block Connector

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2. Disconnect the L27 combination meter assembly connector.
   Fig 9: Identifying L27 Combination Meter Assembly Connector

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

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   3A-26 - L27-7 (+S)	Always	Below 1 Ω

   TEXT IN ILLUSTRATION
   
   

   *1	Front view of wire harness connector (to No. 3 Junction Block)
   *2	Front view of wire harness connector (to Combination Meter Assembly)

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR (NO. 3 JUNCTION CONNECTOR - COMBINATION METER ASSEMBLY) 

OK: Go to next step 

1. Measure the resistance according to the value(s) in the table below.
   Fig 10: Identifying NO. 4 Junction Block

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   Standard Resistance

   Tester Connection	Condition	Specified Condition
   4A-69 - 4A-21	Always	Below 1 Ω

   TEXT IN ILLUSTRATION
   
   

   *1	No. 4 Junction Block

NG → REPLACE NO. 4 JUNCTION BLOCK 

OK: Go to next step 

1. Measure the resistance according to the value(s) in the table below.
   Fig 11: Identifying NO. 3 Junction Block

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   Standard Resistance

   Tester Connection	Condition	Specified Condition
   3A-26 - 3B-85	Always	Below 1 Ω

   TEXT IN ILLUSTRATION
   
   

   *1	No. 3 Junction Block

NG → REPLACE NO. 3 JUNCTION BLOCK 

OK → See step   9