Navigation System (from 12/2010)

NAVIGATION: NAVIGATION SYSTEM: B15C2: Speed Signal Malfunction
B15C2 - Speed Signal Malfunction

DESCRIPTION

The navigation receiver assembly receives a vehicle speed signal from the combination meter assembly and information from the navigation antenna assembly, and then adjusts vehicle position.

The navigation receiver assembly stores this DTC when the difference between the speed information that the navigation antenna assembly 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 (from 12/2010).





(b) While driving the vehicle, compare the "Speed" 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 NAVIGATION RECEIVER ASSEMBLY Removal (from 12/2010)

2. INSPECT COMBINATION METER ASSEMBLY (OUTPUT WAVEFORM)

(a) Check the output waveform.





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

(2) Connect an oscilloscope to terminal E30-5 (+S) and body ground.

(3) Turn the ignition switch to ON.

(4) Turn a wheel slowly.

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





Text in Illustration





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.

NG -- GO TO METER / GAUGE SYSTEM Speedometer Malfunction
OK -- Continue to next step.

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

(a) Disconnect the E39 navigation receiver assembly connector.

(b) Disconnect the E30 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 NAVIGATION RECEIVER ASSEMBLY Removal (from 12/2010)