Last Modified: 04-05-2023 |
6.11:8.1.0 |
Doc ID: RM1000000018FBN |
Model Year Start: 2018 |
Model: Sienna |
Prod Date Range: [11/2017 -
] |
Title: AUDIO / VIDEO: AUDIO AND VISUAL SYSTEM: Vehicle Speed Signal Circuit between Stereo Component Amplifier and Combination Meter; 2018 - 2020 MY Sienna [11/2017 - ] |
Vehicle Speed Signal Circuit between Stereo Component Amplifier and Combination Meter
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DESCRIPTION
The stereo component amplifier assembly receives a vehicle speed signal from the combination meter assembly to control the ASL function.
HINT:
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A voltage of 12 V or 5 V is output from each ECU and then input to the combination meter assembly. The signal is changed to a pulse signal at the transistor in the combination meter assembly. Each ECU controls its respective systems based on this pulse signal.
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If a short occurs in any of the ECUs or in the wire harness connected to an ECU, all systems in the following diagram will not operate normally.
WIRING DIAGRAM
PROCEDURE
1.
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INSPECT COMBINATION METER ASSEMBLY (OUTPUT WAVEFORM)
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(a) Check the output waveform.
(1) Remove the combination meter assembly with the connector(s) still connected.
(2) Connect an oscilloscope to terminal D145-3 (+S) and body ground.
(3) Turn the ignition switch to ON.
(4) Turn a wheel slowly.
(5) Check the signal waveform according to the condition(s) in the table below.
Item
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Condition
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Measurement terminal
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D145-3 (+S) - Body ground
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Tool setting
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5 V/DIV., 20 ms./DIV.
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Vehicle condition
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Wheel being rotated
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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.
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OK
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2.
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INSPECT STEREO COMPONENT AMPLIFIER ASSEMBLY (INPUT WAVEFORM)
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(a) Check the input waveform.
*a
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Component with harness connected
(Stereo Component Amplifier Assembly)
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-
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-
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(1) Remove the stereo component amplifier assembly with the connector(s) still connected.
(2) Connect an oscilloscope to terminal L56-11 (SPD) and body ground.
(3) Turn the ignition switch to ON.
(4) Turn a wheel slowly.
(5) Check the signal waveform according to the condition(s) in the table below.
Item
|
Condition
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Measurement terminal
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L56-11 (SPD) - Body ground
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Tool setting
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5 V/DIV., 20 ms./DIV.
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Vehicle condition
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Wheel being rotated
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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.
OK |
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PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE
(See page
)
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NG |
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REPAIR OR REPLACE HARNESS OR CONNECTOR
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