Vehicle Speed Signal Circuit Between Navigation ECU and Combination Meter

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

Vehicle Speed Signal Circuit between Navigation ECU and Combination Meter

DESCRIPTION

The navigation ECU receives a vehicle speed signal from the combination meter and information from 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 system based on the pulse signal.
- If a short occurs in an ECU, all systems in the diagram below will not operate normally.

WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. CHECK SPEEDOMETER
(a) Drive the vehicle and check if the speedometer in the combination meter functions normally.
OK:
Actual vehicle speed and the speed indicated on the speedometer are the same.

HINT: The vehicle speed sensor is functioning normally when the indicated speed on the speedometer is accurate.

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

2. INSPECT NAVIGATION ECU





(a) Disconnect the navigation ECU connector L16.
(b) Measure voltage.
(1) Jack up either one of the drive wheels.
(2) Move the shift lever to the neutral position.
(3) Turn the ignition switch on (IG).





(4) Measure the voltage between terminal SPD of the navigation ECU and body ground when the drive wheels are turned slowly.
OK:
Voltage pulses as shown in the illustration.
OK -- REPLACE NAVIGATION ECU

NG -- Continue to next step.

3. CHECK HARNESS AND CONNECTOR (COMBINATION METER - NAVIGATION ECU)





(a) Disconnect the navigation ECU connector L16 and combination meter connector E2.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

4. CHECK HARNESS AND CONNECTOR (COMBINATION METER - NAVIGATION ECU)





(a) Disconnect the navigation ECU connector L16 and combination meter connector E2.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:





HINT: If the resistance between terminal SPD and body ground is less than 10 kOhms, there may be a short in a wire harness, connector, or ECU.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR OR EACH ECU
OK -- REPLACE COMBINATION METER