Vehicle Speed Signal Circuit Between Multi-Display And Combination Meter

AUDIO / VISUAL: ELECTRO MULTI VISION SYSTEM: Vehicle Speed Signal Circuit between Multi-display and Combination Meter
- Vehicle Speed Signal Circuit between Multi-display and Combination Meter

DESCRIPTION

The display and navigation module display receives a vehicle speed signal from the combination meter assembly.

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







PROCEDURE

1. INSPECT COMBINATION METER ASSEMBLY (OUTPUT WAVEFORM)

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





(1) Check the output waveform.

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

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

(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 -- CHECK HARNESS AND CONNECTOR

OK -- PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE Problem Symptoms Table

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 -- REPLACE COMBINATION METER ASSEMBLY