Vehicle Speed Signal Circuit

PARK ASSIST / MONITORING: INTUITIVE PARKING ASSIST SYSTEM: Vehicle Speed Signal Circuit
- 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

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 Operation Check.
* The vehicle speed sensor is functioning normally when the indication on the speedometer is normal.

NG -- GO TO METER / GAUGE SYSTEM
OK -- Continue to next step.

2. CHECK COMBINATION METER ASSEMBLY (SPEED SIGNAL)

(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.

Measurement Condition





HINT
As the vehicle speed increases, the wave length shortens.

OK:

Voltage pulses as shown in the illustration.

NG -- CHECK HARNESS AND CONNECTOR (CLEARANCE WARNING ECU - COMBINATION METER ASSEMBLY)

OK -- PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE Intuitive Parking Assist System

3. CHECK HARNESS AND CONNECTOR (CLEARANCE WARNING ECU - COMBINATION METER ASSEMBLY)

(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:





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR

OK -- REPLACE COMBINATION METER ASSEMBLY Removal