B15C2

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 combination meter assembly and information about the GPS antenna, and then adjusts vehicle position.

The display and navigation module display stores this DTC when the difference between the speed information that the GPS antenna receives and the SPD pulse received from the combination meter assembly becomes large.

HINT
* A voltage of 12 V or 5 V is output from each ECU and then input to the combination meter assembly. The signal is changed to a pulse signal at the transistor in the combination meter 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





INSEPCTION PROCEDURE

PROCEDURE

1. CHECK VEHICLE SENSOR (OPERATION CHECK)

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





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

OK:

The readings are almost equal.

NG -- INSPECT COMBINATION METER ASSEMBLY (OUTPUT WAVEFORM)

OK -- REPLACE DISPLAY AND NAVIGATION MODULE DISPLAY Removal

2. INSPECT COMBINATION METER ASSEMBLY (OUTPUT WAVEFORM)

(a) Check the input waveform.





(1) Reconnect the C8 combination meter assembly connector.

(2) Remove the combination meter assembly with the connector(s) still connected.

(3) Connect an oscilloscope to terminal C8-21 (+S) and body ground.

(4) Turn the ignition switch to ON.

(5) Turn the wheel slowly.

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





Text in Illustration





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.

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

(a) Disconnect the D24 display and navigation module display connector.

(b) Disconnect the C8 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 DISPLAY AND NAVIGATION MODULE DISPLAY Removal