Vehicle Speed Signal Circuit Between Navigation Receiver Assembly and Combination Meter

NAVIGATION: NAVIGATION SYSTEM: Vehicle Speed Signal Circuit between Navigation Receiver Assembly and Combination Meter

Vehicle Speed Signal Circuit between Navigation Receiver Assembly and Combination Meter

DESCRIPTION

The navigation receiver assembly receives a vehicle speed signal from the combination meter and information about the GPS antenna, and then adjusts vehicle position.
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 the respective systems based on the pulse signal.
- If a short occurs in any of the ECUs or in the wire harness connected to an ECU, all systems in the diagram below will not operate normally.

WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. INSPECT COMBINATION METER ASSEMBLY (OUTPUT WAVEFORM)




(a) Check the output waveform.
(1) Remove the combination meter assembly with the connector still connected.
(2) Connect an oscilloscope to terminals E1-9 (+S) and body ground.
(3) Ignition switch on (IG).
(4) Turn the wheel slowly.
(5) Check the signal waveform according to the condition(s) in the table below.






OK:
The waveform is displayed as 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.

NG -- GO TO METER / GAUGE SYSTEM
OK -- Continue to next step.
2. CHECK HARNESS AND CONNECTOR (NAVIGATION RECEIVER ASSEMBLY - COMBINATION METER)




(a) Disconnect navigation receiver assembly connector E5 and combination meter connector E1.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:






NG -- CHECK HARNESS AND CONNECTOR (NAVIGATION RECEIVER ASSEMBLY - JUNCTION CONNECTOR)
OK -- REPLACE NAVIGATION RECEIVER ASSEMBLY
3. CHECK HARNESS AND CONNECTOR (NAVIGATION RECEIVER ASSEMBLY - JUNCTION CONNECTOR)




(a) Disconnect junction connector E24.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (NAVIGATION RECEIVER ASSEMBLY - JUNCTION CONNECTOR)
OK -- REPAIR OR REPLACE HARNESS OR CONNECTOR (JUNCTION CONNECTOR)