Vehicle Speed Signal Circuit between Stereo Component Amplifier and Combination Meter: Procedure
- CHECK HARNESS AND CONNECTOR
- Disconnect the stereo component amplifier assembly connector.
- Disconnect the combination meter assembly connector.
- Measure the resistance according to the value(s) in the table below.STANDARD RESISTANCE
Tester Connection Condition Specified Condition P30-11 (SPD) - J34-5 (+S) Always Below 1 Ω P30-11 (SPD) - Body ground Always 10 kΩ or higher TEXT IN ILLUSTRATION*1 Front view of wire harness connector
(to Stereo Component Amplifier Assembly)*2 Front view of wire harness connector
(to Combination Meter Assembly)
NG → REPAIR OR REPLACE HARNESS OR CONNECTOR
OK: Go to next step
- INSPECT COMBINATION METER ASSEMBLY (OUTPUT WAVEFORM)
- Reconnect the combination meter assembly connector.
- Check the output waveform.
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
- Connect an oscilloscope to terminal P30-11 (SPD) and body ground.
- Turn the engine switch on (IG).
- Turn a wheel slowly.
- Check the signal waveform according to the condition(s) in the table below.
Item Condition Measurement terminal P30-11 (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.
TEXT IN ILLUSTRATION*1 Front view of wire harness connector
(to Stereo Component Amplifier Assembly)
NG → See step 4
OK → See step 3
- REPLACE STEREO COMPONENT AMPLIFIER ASSEMBLY. Refer to REMOVAL
- REPLACE COMBINATION METER ASSEMBLY. Refer to REMOVAL