B15C2

NAVIGATION / MULTI INFO DISPLAY: 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 (No. 3 meter circuit plate) and information from the navigation antenna, and then adjusts vehicle position.

The navigation receiver assembly 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 (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 combination meter assembly (No. 3 meter circuit plate). The signal is changed to a pulse signal at the transistor in the combination meter assembly (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

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 "SPD" 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 (NO. 3 METER CIRCUIT PLATE OUTPUT WAVEFORM)

OK -- REPLACE NAVIGATION RECEIVER ASSEMBLY Removal

2. INSPECT COMBINATION METER ASSEMBLY (NO. 3 METER CIRCUIT PLATE 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 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. CHECK HARNESS AND CONNECTOR (NAVIGATION RECEIVER ASSEMBLY - COMBINATION METER ASSEMBLY)

(a) Disconnect the L42 navigation receiver assembly connector.

(b) Disconnect the L27 combination meter assembly connector.

Text in Illustration

NG -- CHECK HARNESS AND CONNECTOR (NAVIGATION RECEIVER ASSEMBLY - NO. 4 JUNCTION CONNECTOR)

OK -- REPLACE NAVIGATION RECEIVER ASSEMBLY Removal

4. CHECK HARNESS AND CONNECTOR (NAVIGATION RECEIVER ASSEMBLY - NO. 4 JUNCTION CONNECTOR)

(a) Disconnect the L42 navigation receiver assembly connector.

(b) Disconnect the 4A No. 4 junction block connector.

Text in Illustration

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (NAVIGATION RECEIVER ASSEMBLY - NO. 4 JUNCTION CONNECTOR)
OK -- Continue to next step.

5. CHECK HARNESS AND CONNECTOR (No. 4 JUNCTION CONNECTOR - NO. 3 JUNCTION CONNECTOR)

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

(b) Disconnect the 3B No. 3 junction block connector.

Text in Illustration

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (NO. 4 JUNCTION CONNECTOR - NO. 3 JUNCTION CONNECTOR)
OK -- Continue to next step.

6. CHECK HARNESS AND CONNECTOR (NO. 3 JUNCTION CONNECTOR - COMBINATION METER ASSEMBLY)

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

(b) Disconnect the L27 combination meter assembly connector.

Text in Illustration

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (NO. 3 JUNCTION CONNECTOR - COMBINATION METER ASSEMBLY)
OK -- Continue to next step.

7. REPLACE 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. REPLACE 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 NAVIGATION RECEIVER ASSEMBLY Removal