WIPER AND WASHER SYSTEM(w/ Rain Sensor) Speed Signal Circuit
|DTC Code||DTC Name|
|Speed Signal Circuit|
The windshield wiper relay assembly receives a vehicle speed signal from the combination meter assembly to control the auto wiper system.
A voltage of 12 V or 5 V is output from the combination meter assembly and then input to the skid control ECU.
A voltage of 12 V or 5 V is output from each ECU or relay 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 system 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 following diagram will not operate normally.
CHECK HARNESS AND CONNECTOR (WINDSHIELD WIPER RELAY ASSEMBLY - COMBINATION METER ASSEMBLY)
*1: for Radio Receiver Type
*2: for Radio and Display Type
Disconnect the G16 combination meter assembly connector.
Disconnect the G85 windshield wiper relay assembly connector.
Disconnect the M32 stereo compornent amplifier assembly connector.
Disconnect the N39 vehicle approchaing speaker controller connector.
Disconnect the G84 certification ECU (smart key ECU assembly) connector.
Disconnect the A67 headlight leveling ECU assembly connector.
Disconnect the M38 DCM connector.
Disconnect the G48 radio receiver assembly connector.*1
Disconnect the G143 radio and display receiver assembly connector.*2
Measure the resistance according to the value(s) in the table below.
G85-24 (SPD) - G16-6 (+S)
Below 1 Ω
G85-24 (SPD) - Body ground
10 kΩ or higher
REPAIR OR REPLACE HARNESS OR CONNECTOROK
CHECK COMBINATION METER ASSEMBLY (OUTPUT WAVEFORM)
Component with harness connected
(Combination Meter Assembly)
Remove the combination meter assembly with the connector(s) still connected.
Connect an oscilloscope to terminal G16-6 (+S) and body ground.
Check the signal waveform according to the condition(s) in the table below.
Terminal No. (Symbol)
G16-6 (+S) - Body ground
5 V/DIV., 20 ms./DIV.
Ignition switch ON, wheel being rotated
The waveform is displayed as shown in the illustration.Tip:
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.