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 combination meter assembly and information from the navigation antenna, and then adjusts the vehicle position on the map.

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 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





INSPECTION PROCEDURE

PROCEDURE

1. CHECK VEHICLE SENSOR (OPERATION CHECK)

(a) Enter the "Vehicle Sensors" screen. Refer to Check GPS & Vehicle Sensors in Operation Check Operation Check.





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

HINT
The combination meter assembly receives the vehicle speed signal from the skid control ECU via the direct line. Therefore, perform the following inspection referring to values on the Data List of the skid control ECU because it is the source of the vehicle speed signal.

OK:

Vehicle speed displayed on the "Vehicle Sensors" screen is almost the same as the actual vehicle speed measured using the Techstream Data List / Active Test.

NG -- CHECK HARNESS AND CONNECTOR

OK -- REPLACE DISPLAY AND NAVIGATION MODULE DISPLAY Removal

2. CHECK HARNESS AND CONNECTOR

(a) Disconnect the K46 display and navigation module display connector.

(b) Disconnect the K31 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 -- Continue to next step.

3. INSPECT COMBINATION METER ASSEMBLY (OUTPUT WAVEFORM)

(a) Reconnect the K31 combination meter assembly connector.

(b) Disconnect the K46 display and navigation module display connector.

(c) Check the output waveform.





(1) Connect an oscilloscope to terminal K46-18 (SPD) and body ground.

(2) Turn the power switch on (IG).

(3) Turn a wheel slowly.

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









OK:

The waveform is similar to that 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.

Text in Illustration





NG -- REPLACE COMBINATION METER ASSEMBLY Removal

OK -- REPLACE DISPLAY AND NAVIGATION MODULE DISPLAY Removal