Navigation System (for HDD)

NAVIGATION: NAVIGATION SYSTEM (for HDD): B15C2: Speed Signal Malfunction
B15C2 - Speed Signal Malfunction

DESCRIPTION

The display and navigation module display receives a vehicle speed signal from the No. 1 meter ECU sub-assembly and information about the navigation antenna, and then adjusts vehicle position.

The display and navigation module display stores this DTC when the difference between the speed information that the navigation antenna receives and the SPD pulse received from the No. 1 meter ECU sub-assembly becomes large.

HINT
* A voltage of 12 V or 5 V is output from each ECU and then input to the No. 1 meter ECU sub-assembly. The signal is changed to a pulse signal at the transistor in the No. 1 meter ECU sub-assembly. 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. CHECK NO. 1 METER ECU SUB-ASSEMBLY

(a) Drive the vehicle and check if the function of the speedometer in the No.1 meter ECU sub-assembly is normal.

OK:

Actual vehicle speed and the speed indicated on the speedometer are the same.

HINT
The vehicle speed sensor is functioning normally when the indication on the speedometer is normal.

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

2. CHECK VEHICLE SENSOR (OPERATION CHECK)

(a) Enter the "GPS & Vehicle Sensor" (Vehicle Sensors) Operation Check.





(b) While driving the vehicle, compare the "SPD" indicator to the reading on the speedometer. Check if these readings are equal or almost equal.

OK:

The readings are equal or almost equal.

NG -- CHECK NO. 1 METER ECU SUB-ASSEMBLY (SPEED SIGNAL)
OK -- Continue to next step.

3. CHECK HARNESS AND CONNECTOR (DISPLAY AND NAVIGATION MODULE DISPLAY - NO. 1 METER ECU)

(a) Disconnect the L59 display and navigation module display connector.

(b) Disconnect the L10 No. 1 meter ECU sub-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 -- Continue to next step.

4. CHECK NO. 1 METER ECU SUB-ASSEMBLY (SPEED SIGNAL)

(a) Remove the No. 1 meter ECU sub-assembly with the connector(s) still connected.





(b) Connect an oscilloscope to terminal L10-10 (+S) and body ground.

(c) Turn the engine switch on (IG).

(d) Check the signal waveform according to the condition(s) in the table below.

Measurement Condition





OK:

The waveform display is as shown in the illustration.

HINT
When the system is function normally, one wheel revolution generates 4 pulses.

As the vehicle speed increases, the width indicated by (A) in the illustration narrows.

Text in Illustration





NG -- REPLACE NO. 1 METER ECU SUB-ASSEMBLY Removal

OK -- REPLACE DISPLAY AND NAVIGATION MODULE DISPLAY Removal