| Last Modified: 11-29-2007 | 1.6 J | |
| Service Category: Audio/Visual/Telematics | Section: Park Assist/Monitoring | |
| Model Year: 2008 | Model: Sequoia | Doc ID: RM000002CJC005X |
| Title: PARK ASSIST / MONITORING: INTUITIVE PARKING ASSIST SYSTEM: DESCRIPTION (2008 Sequoia) | ||
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Vehicle Speed Signal Circuit |
DESCRIPTION
This circuit sends a speed signal from the combination meter assembly to the clearance warning ECU.
HINT:
- A voltage of 12 V or 5 V is output from each ECU and then input to the combination meter. The signal is changed to a pulse signal at the transistor in the combination meter. Each ECU controls its respective system based on the pulse signal.
- If a short occurs in any of the ECUs or in the wire harness connected to an ECU, both systems in the diagram below will not operate normally.
WIRING DIAGRAM
INSPECTION PROCEDURE
PROCEDURE
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1. |
INSPECT OPERATION OF SPEEDOMETER |
(a) Drive the vehicle and check if the function of the speedometer on the combination meter is normal.
OK:
Actual vehicle speed and the speed indicated on the speedometer are the same.
HINT:
-
The speed indicated on the speedometer has an allowable margin of error. This can be tested using a speedometer tester (calibrated chassis dynamometer). For details about testing and the margin of error, refer to "Operation Check" in the meter/gauge system
.
- The vehicle speed sensor is functioning normally when the indication on the speedometer is normal.
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2. |
CHECK COMBINATION METER ASSEMBLY (SPEED SIGNAL) |
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(a) Disconnect the H43 clearance warning ECU connector. |
(b) Jack up the drive wheels.
(c) Move the shift lever to N.
(d) Turn the ignition switch to ON.
(e) Using an oscilloscope, check the signal waveform of the meter.
Waveform
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Tester Connection |
H43-3 (SPD) - Body ground |
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Tester Range |
5 V/DIV., 20 msec./DIV. |
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Vehicle Condition |
Drive vehicle at 20 km/h (12 mph) |
HINT:
As the vehicle speed increases, the wave length shortens.
OK:
Voltage pulses as shown in the illustration.
(f) Reconnect the clearance warning ECU connector.
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3. |
CHECK HARNESS AND CONNECTOR (CLEARANCE WARNING ECU - COMBINATION METER ASSEMBLY) |
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(a) Disconnect the H43 clearance warning ECU connector. |
(b) Disconnect the H37 combination meter assembly connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
H43-3 (SPD) - H37-35 (+S) |
Always |
Below 1 Ω |
|
H43-3 (SPD) - Body ground |
Always |
10 kΩ or higher |
(d) Reconnect the clearance warning ECU connector.
(e) Reconnect the combination meter assembly connector.
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