Toyota Camry (XV70): Vehicle Speed Signal Circuit between Stereo Component Amplifier and Combination Meter
DESCRIPTION
The stereo component amplifier assembly receives a vehicle speed signal from the combination meter assembly to control the ASL function.
HINT:
- 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.
- 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
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PROCEDURE
| 1. |
INSPECT COMBINATION METER ASSEMBLY (OUTPUT WAVEFORM) |
| (a) Check the output waveform. (1) Remove the combination meter assembly with the connector(s) still connected. (2) Connect an oscilloscope to terminal K21-6 (+S) and body ground. (3) Turn the engine switch on (IG). (4) Turn a wheel slowly. (5) Check the signal waveform according to the condition(s) in the table below.
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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| NG | .gif) | GO TO METER / GAUGE SYSTEM
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| 2. |
INSPECT STEREO COMPONENT AMPLIFIER ASSEMBLY (INPUT WAVEFORM) |
(a) Check the input waveform.
|
*a | Component with harness connected (Stereo Component Amplifier Assembly) |
- | - |
(1) Remove the stereo component amplifier assembly with the connector(s) still connected.
(2) Connect an oscilloscope to terminal K10-11 (SPD) and body ground.
(3) Turn the engine 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 |
K10-11 (SPD) - 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.
| OK | | PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE
|
| NG | | REPAIR OR REPLACE HARNESS OR CONNECTOR |
READ NEXT:
Reverse Signal Circuit
DESCRIPTION The radio and display receiver assembly receives a reverse signal from the BKUP LP relay. WIRING DIAGRAM
PROCEDURE
1.
CHECK BACK-UP LIGHT (a) Move the shift lever to R and
Reverse Signal Circuit between Radio Receiver Assembly and Navigation ECU
DESCRIPTION This circuit includes the navigation ECU and radio and display receiver assembly. WIRING DIAGRAM
PROCEDURE
1.
CHECK HARNESS AND CONNECTOR (RADIO AND DISPLAY RECEIVER ASSEMBLY
Start Up Signal Circuit between Radio Receiver Assembly and Navigation ECU
DESCRIPTION This circuit includes the navigation ECU and radio and display receiver assembly. WIRING DIAGRAM
PROCEDURE
1.
CHECK HARNESS AND CONNECTOR (RADIO AND DISPLAY RECEIVER ASSEMBLY
SEE MORE:
How To Proceed With Troubleshooting
CAUTION / NOTICE / HINT HINT: *: Use the Techstream. PROCEDURE
1.
VEHICLE BROUGHT TO WORKSHOP
NEXT
2.
CUSTOMER PROBLEM ANALYSIS
HINT:
In troubleshooting, confirm that the problem symptoms have been accurately identified. Preconceptions
General Information
GENERAL INFORMATION
A large number of ECU controlled systems are used in this vehicle. In general, ECU controlled systems are considered to be very intricate, requiring a high level of technical knowledge to troubleshoot. However, most problem checking procedures only involve inspecting the ECU
