DESCRIPTION
The combination meter assembly receives the vehicle speed signal from this circuit. The wheel speed sensors produce an output that varies according to the vehicle speed. The wheel speed sensor output is received by the skid control ECU which uses this information to create the vehicle speed sensor signal*a. The vehicle speed sensor signal consists of pulses sent to the combination meter assembly from the skid control ECU. To create this signal, 12 V is output from IG2 which is behind a resistor in the combination meter assembly. This voltage is sent to the skid control ECU. The pulse signal is created by switching the transistor in the skid control ECU on and off, making the voltage on the wire drop to 0 V. A similar system is used for the output of this signal from the combination meter assembly via terminal +S. A voltage of 12 V or 5 V is applied to terminal +S from each ECU or relay that is connected to this terminal. The transistor in the combination meter assembly is controlled by the signal from the skid control ECU. When this transistor is turned on, this transistor makes the voltage supplied by the various ECUs (via their respective internal resistors) drop to 0 V. Each ECU connected to terminal +S of the combination meter assembly controls its respective system based on the pulse signal.
*a: This vehicle speed sensor signal is created by the skid control ECU. There is no actual component that is referred to as the vehicle speed sensor. In addition, for some other systems, vehicle speed information may be exchanged using CAN communication.
Tech Tips
This circuit is used for the systems connected to terminal +S. This signal is not used for combination meter assembly operation. Combination meter assembly components such as the speedometer operate using data received via CAN communication.
WIRING DIAGRAM
INSPECTION PROCEDURE
PROCEDURE
INSPECT ECU TERMINAL VOLTAGE (INPUT VOLTAGE)
*a | Front view of wire harness connector (to Combination Meter Assembly) |
Disconnect the H19 connector.
Measure the voltage according to the value(s) in the table below.
Standard Voltage | ||||||
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|
Tech Tips
If any of the ECUs specified in the wiring diagram supplies power to the combination meter assembly, the combination meter assembly will output a waveform.
NG |
CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - JUNCTION CONNECTOR) Click here |
OK |
INSPECT COMBINATION METER ASSEMBLY (OUTPUT VOLTAGE)
Reconnect the H19 connector.
*a | Front view of wire harness connector (to Skid Control ECU) |
Disconnect the A61 connector.
Measure the voltage according to the value(s) in the table below.
Standard Voltage | ||||||
---|---|---|---|---|---|---|
|
NG |
CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - SKID CONTROL ECU) Click here |
OK |
INSPECT SKID CONTROL ECU (INPUT WAVEFORM)
*a | Component with harness connected (Combination Meter Assembly) |
Check the input waveform.
Reconnect the A61 connector.
Remove the combination meter assembly with the connector(s) still connected.
Connect an oscilloscope to terminal H19-39 (SI) and body ground.
Turn the power switch on (IG).
Turn the wheel slowly.
Check the signal waveform according to the condition(s) in the table below.
Item | Condition |
---|---|
Tool setting | 5 V/DIV., 20 ms/DIV. |
Vehicle condition | Wheel being rotated |
OK |
---|
The waveform is displayed as shown in the illustration. |
Tech Tips
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.
Result | ||||||||
---|---|---|---|---|---|---|---|---|
|
B |
REPLACE SKID CONTROL ECU Click here |
C |
REPLACE SKID CONTROL ECU Click here |
A |
REPLACE COMBINATION METER ASSEMBLY Click here
CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - SKID CONTROL ECU)
Disconnect the H19 and A61 connectors.
Measure the resistance according to the value(s) in the table below.
Standard Resistance | |||||||||
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|
NG |
REPAIR OR REPLACE HARNESS OR CONNECTOR |
OK |
REPLACE COMBINATION METER ASSEMBLY Click here
CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - JUNCTION CONNECTOR)
Disconnect the junction connector.
Measure the resistance according to the value(s) in the table below.
Standard Resistance | |||||||||
---|---|---|---|---|---|---|---|---|---|
|
NG |
REPAIR OR REPLACE HARNESS OR CONNECTOR |
OK |
CHECK HARNESS AND CONNECTOR (JUNCTION CONNECTOR)
Inspect for a short in the circuit that is connected to the junction block connector shown in the wiring diagram.
Tech Tips
If voltage is not present, it is possible that an ECU or circuit has a malfunction. The malfunctioning ECU or circuit will be diagnosed in the following steps.
Disconnect the 3B connector.
Measure the voltage according to the value(s) in the table below.
Standard Voltage | |||||||||||||||||||||
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|
*a | Front view of wire harness connector (to Junction Connector) |
Result | ||||||
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|
B |
REPLACE JUNCTION CONNECTOR |
A |
SYSTEM CHECK
Select the circuit for which voltage was not present in step 6.
Result | |||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
*1: w/ Auto Wiper System
*2: w/ Automatic Type Headlight Beam Level Control
*3: w/ Navigation System (for DVD)
*4: w/ Navigation System (for HDD)
B |
CHECK HARNESS AND CONNECTOR (WINDSHIELD WIPER RELAY ASSEMBLY CIRCUIT) Click here |
C |
CHECK HARNESS AND CONNECTOR (HEADLIGHT LEVELING ECU ASSEMBLY CIRCUIT) Click here |
D |
SYSTEM CHECK Click here |
A |
CHECK HARNESS AND CONNECTOR (POWER MANAGEMENT CONTROL ECU CIRCUIT)
Disconnect the H3 connector.
Measure the resistance according to the value(s) in the table below.
Standard Resistance | ||||||
---|---|---|---|---|---|---|
|
NG |
REPAIR OR REPLACE HARNESS OR CONNECTOR |
OK |
REPLACE POWER MANAGEMENT CONTROL ECU Click here
CHECK HARNESS AND CONNECTOR (WINDSHIELD WIPER RELAY ASSEMBLY CIRCUIT)
Disconnect the H75 connector.
Measure the resistance according to the value(s) in the table below.
Standard Resistance | ||||||
---|---|---|---|---|---|---|
|
NG |
REPAIR OR REPLACE HARNESS OR CONNECTOR |
OK |
REPLACE WINDSHIELD WIPER RELAY ASSEMBLY Click here
CHECK HARNESS AND CONNECTOR (HEADLIGHT LEVELING ECU ASSEMBLY CIRCUIT)
Disconnect the A46 connector.
Measure the resistance according to the value(s) in the table below.
Standard Resistance | ||||||
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|
Result | ||||||||
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|
B |
REPLACE HEADLIGHT LEVELING ECU ASSEMBLY Click here |
C |
REPAIR OR REPLACE HARNESS OR CONNECTOR |
A |
REPLACE HEADLIGHT LEVELING ECU ASSEMBLY Click here
SYSTEM CHECK
Select the circuit for which voltage was not present in step 6.
Result | ||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
|
*1: w/ Navigation System (for DVD)
*2: w/ Navigation System (for HDD)
B |
CHECK HARNESS AND CONNECTOR (RADIO RECEIVER CIRCUIT, NAVIGATION RECEIVER CIRCUIT) Click here |
A |
CHECK HARNESS AND CONNECTOR (STEREO COMPONENT AMPLIFIER ASSEMBLY CIRCUIT)
Disconnect the H56*1 or H55*2 connector.
Measure the resistance according to the value(s) in the table below.
Standard Resistance | |||||||||
---|---|---|---|---|---|---|---|---|---|
|
*1: w/ Navigation System
*2: w/o Navigation System
NG |
REPAIR OR REPLACE HARNESS OR CONNECTOR |
OK |
REPLACE STEREO COMPONENT AMPLIFIER ASSEMBLY Click here
CHECK HARNESS AND CONNECTOR (RADIO RECEIVER CIRCUIT, NAVIGATION RECEIVER CIRCUIT)
Disconnect the H47*1, H52*2, or H60*3 connector.
Measure the resistance according to the value(s) in the table below.
Standard Resistance | ||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
|
*1: w/o Navigation System, w/ Built-in Type Amplifier
*2: w/o Navigation System, w/ Separate Type Amplifier
*3: w/ Navigation System
Result | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|
|
B |
REPLACE NAVIGATION COMPUTER SUB-ASSEMBLY Click here |
C |
REPLACE DISPLAY AND NAVIGATION MODULE DISPLAY Click here |
D |
REPAIR OR REPLACE HARNESS OR CONNECTOR |
A |
REPLACE RADIO RECEIVER ASSEMBLY Click here