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 Sensor in Operation Check Operation Check.





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

HINT
The meter ECU receives the vehicle speed signal from the skid control ECU via CAN communication. 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 -- INSPECT COMBINATION METER ASSEMBLY (OUTPUT WAVEFORM)

OK -- REPLACE DISPLAY AND NAVIGATION MODULE DISPLAY Removal

2. INSPECT COMBINATION METER ASSEMBLY (OUTPUT WAVEFORM)

(a) Check the output waveform.





(1) Reconnect the E20 combination meter assembly connector.

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

(3) Connect an oscilloscope to terminal E20-12 (+S) and body ground.

(4) Turn the engine switch on (ON).

(5) Turn a wheel slowly.

(6) 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 -- GO TO METER / GAUGE SYSTEM Speed Signal Circuit
OK -- Continue to next step.

3. CHECK HARNESS AND CONNECTOR

(a) Disconnect the E62 display and navigation module display connector.

(b) Disconnect the E20 combination meter assembly connector.

(c) Measure the resistance according to the value(s) in the table below.

Standard Resistance:





NG -- CHECK HARNESS AND CONNECTOR

OK -- REPLACE DISPLAY AND NAVIGATION MODULE DISPLAY Removal

4. CHECK HARNESS AND CONNECTOR

(a) Disconnect the E62 display and navigation module display connector.

(b) Disconnect the 4G No. 4 junction block 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.

5. CHECK HARNESS AND CONNECTOR

(a) Disconnect the 4M No. 4 junction block connector.

(b) Disconnect the 3F No. 3 junction block 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.

6. CHECK HARNESS AND CONNECTOR

(a) Disconnect the 3L No. 3 junction block connector.

(b) Disconnect the E20 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.

7. INSPECT NO. 4 JUNCTION BLOCK

(a) Measure the resistance according to the value(s) in the table below.





Standard Resistance:





Text in Illustration





NG -- REPLACE NO. 4 JUNCTION BLOCK
OK -- Continue to next step.

8. INSPECT NO. 3 JUNCTION BLOCK

(a) Measure the resistance according to the value(s) in the table below.





Standard Resistance:





Text in Illustration





NG -- REPLACE NO. 3 JUNCTION BLOCK

OK -- REPLACE DISPLAY AND NAVIGATION MODULE DISPLAY Removal