Speed Signal Circuit

LIGHTING: LIGHTING SYSTEM: Speed Signal Circuit
- Speed Signal Circuit

DESCRIPTION

The headlight leveling ECU assembly receives front wheel speed sensor signals from the skid control ECU.

WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. CHECK DTC (VEHICLE STABILITY CONTROL SYSTEM)

(a) Check that vehicle stability control system DTCs are not output.

OK:

VSC system DTC is not output.

NG -- GO TO VEHICLE STABILITY CONTROL SYSTEM
OK -- Continue to next step.

2. CHECK SPEED SENSOR SIGNAL WAVEFORM

(a) Check the speed signal waveform.





(1) Connect an oscilloscope to terminals A61-5 (SPDL) and body ground or terminals A61-6 (SPDR) and body ground.

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

(3) Turn the front wheel slowly.

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





OK:

The waveform is similar to that shown in the illumination.

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 -- CHECK HARNESS AND CONNECTOR (HEADLIGHT LEVELING ECU ASSEMBLY - SKID CONTROL ECU)

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

3. CHECK HARNESS AND CONNECTOR (HEADLIGHT LEVELING ECU ASSEMBLY - SKID CONTROL ECU)

(a) Disconnect the A61 headlight leveling ECU assembly connector.

(b) Disconnect the A58 skid control ECU 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.

4. INSPECT HEADLIGHT LEVELING ECU ASSEMBLY (OUTPUT VOLTAGE)

(a) Disconnect the A58 skid control ECU connector.

(b) Measure the voltage according to the value(s) in the table below.

Standard Voltage:





NG -- REPLACE HEADLIGHT LEVELING ECU ASSEMBLY

OK -- REPLACE BRAKE ACTUATOR ASSEMBLY (SKID CONTROL ECU)