B15C2

NAVIGATION / MULTI INFO DISPLAY: NAVIGATION SYSTEM (for Navigation Receiver Type): B15C2: Speed Signal Malfunction
B15C2 - Speed Signal Malfunction

DESCRIPTION

The navigation ECU sub-assembly receives a vehicle speed signal from the No. 3 meter circuit plate and information from the navigation antenna assembly, and then adjusts the vehicle position.

The navigation ECU sub-assembly stores this DTC when the difference between the speed information that the navigation antenna assembly receives and the SPD pulse received from the No. 3 meter circuit plate becomes large.

HINT
* A voltage of 12 V or 5 V is output from each ECU and then input to the No. 3 meter circuit plate. The signal is changed to a pulse signal at the transistor in the No. 3 meter circuit plate. 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

NOTICE:
After replacing the navigation ECU sub-assembly of vehicles subscribed to pay-type satellite radio broadcasts, registration of the XM radio ID is necessary.

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 speedometer. Check if these readings are almost equal.

HINT
The No. 3 meter circuit plate 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 NO. 3 METER CIRCUIT PLATE (OUTPUT WAVEFORM)

OK -- REPLACE NAVIGATION ECU SUB-ASSEMBLY Removal

2. INSPECT NO. 3 METER CIRCUIT PLATE (OUTPUT WAVEFORM)

(a) Check the output waveform.





(1) Remove the No. 3 meter circuit plate with the connector(s) still connected.

(2) Connect an oscilloscope to terminal L27-7 (+S) and body ground.

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

(4) Turn a wheel slowly.

(5) 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. INSPECT NAVIGATION ECU SUB-ASSEMBLY (INPUT WAVEFORM)

(a) Check the input waveform.





(1) Remove the navigation ECU sub-assembly with the connector(s) still connected.

(2) Connect an oscilloscope to terminal L130-17 (SPD) and body ground.

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

(4) Turn a wheel slowly.

(5) 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 -- REPAIR OR REPLACE HARNESS OR CONNECTOR (NAVIGATION ECU SUB-ASSEMBLY - NO. 3 METER CIRCUIT PLATE)

OK -- REPLACE NAVIGATION ECU SUB-ASSEMBLY Removal