Vehicle Speed Signal Circuit between Stereo Component Amplifier and Combination Meter
DESCRIPTION
The stereo
component amplifier assembly receives a vehicle speed signal from the
combination meter assembly to control the ASL function.
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 its
respective systems based on this 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.
WIRING DIAGRAM
PROCEDURE
| 1. |
INSPECT COMBINATION METER ASSEMBLY (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 G16-6 (+S) 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. |
Item | Condition | |
Measurement terminal |
G16-6 (+S) - Body ground | |
Tool setting | 5 V/DIV., 20 ms./DIV. | |
Vehicle condition |
Wheel being rotated | 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. |
 |
|
*a | Component with harness connected
(Combination Meter Assembly) | | |
| NG |
 | GO TO METER / GAUGE SYSTEM |
|
OK |
 | |
| 2. |
INSPECT STEREO COMPONENT AMPLIFIER ASSEMBLY (INPUT WAVEFORM) |
(a) Check the input waveform.
|
*a | Component with harness connected
(Stereo Component Amplifier Assembly) |
- | - |
(1) Remove the stereo component amplifier assembly with the connector(s) still connected.
(2) Connect an oscilloscope to terminal G8-11 (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.
|
Item | Condition |
|
Measurement terminal |
G8-11 (SPD) - Body ground |
|
Tool setting | 5 V/DIV., 20 ms./DIV. |
|
Vehicle condition | Wheel being rotated |
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.
| OK | |
PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE |
| NG |
| REPAIR OR REPLACE HARNESS OR CONNECTOR |
Voice Guidance Circuit between Radio Receiver and Stereo Component Amplifier
DESCRIPTION
This circuit is used when the voice switch of the steering pad switch assembly is pushed.
Using this circuit, the radio and display receiver assembly sends signals to the stereo component amplifier assembly.
WIRING DIAGRAM
PROCEDURE
| 1. |
CHECK HARNESS AND CONNECTOR (RADIO AND DISPLAY RECEIVER ASSEMBLY - STEREO COMPONENT AMPLIFIER ASSEMBLY) |
(a) Disconnect the G14 radio and display receiver assembly connector.
(b) Disconnect the G8 stereo component amplifier assembly connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
|
Tester connection | Condition |
Specified condition |
|
G14-3 (RL+) - G8-15 (II1+) |
Always | Below 1 Ω |
|
G14-8 (RL-) - G8-14 (II1-) |
Always | Below 1 Ω |
|
G8-18 (SLD1) - Body ground |
Always | 10 kΩ or higher |
|
G14-3 (RL+) or G8-15 (II1+) - Body ground |
Always | 10 kΩ or higher |
|
G14-8 (RL-) or G8-14 (II1-) - Body ground |
Always | 10 kΩ or higher |
| OK |
 | PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE |
| NG |
| REPAIR OR REPLACE HARNESS OR CONNECTOR |
Voice Guidance does not Function
WIRING DIAGRAM
PROCEDURE
| 1. |
CHECK VOICE GUIDANCE SETTING |
(a) Check that the voice guidance setting is not off.
OK:
Voice guidance setting is not off.
| NG |
 | CHANGE VOICE GUIDANCE SETTING TO ON |
|
OK |
 | |
| 2. |
CHECK HARNESS AND CONNECTOR (RADIO AND DISPLAY RECEIVER ASSEMBLY - NAVIGATION ECU) |
(a) Disconnect the G1 radio and display receiver assembly connector.
(b) Disconnect the G13 navigation ECU connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
|
Tester Connection | Condition |
Specified Condition |
|
G1-22 (SI+) - G13-6 (VOI+) |
Always | Below 1 Ω |
|
G1-23 (SI-) - G13-7 (VOI-) |
Always | Below 1 Ω |
|
G1-22 (SI+) or G13-6 (VOI+) - Body ground |
Always | 10 kΩ or higher |
|
G1-23 (SI-) or G13-7 (VOI-) - Body ground |
Always | 10 kΩ or higher |
|
G13-8 (SLD1) - Body ground |
Always | 10 kΩ or higher |
| OK |
| PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE |
| NG |
| REPAIR OR REPLACE HARNESS OR CONNECTOR |
