Vehicle Speed Sensor (VSS) Inspection

VEHICLE SPEED SENSOR(VSS) INSPECTION [ATX]
Visual Inspection
1. Remove the VSS.
2. Make sure that the sensor is free of any metallic shavings or particles.
- If any are found on the sensor, clean them off.
3. Install the VSS.

Frequency Inspection Using the NGS





1. Connect the NGS to the DLC-2.
2. Start the engine.





3. Connect NGS test lead (+) to the VSS connector B terminal.
4. Select the "FREQUENCY METER" function of the DIGITAL MEASUREMENT SYSTEM menu and press TRIGGER.
5. Press the LINK key to select VS PID.
6. Select the "PID/DATA MONITOR" function on the NGS display and press TRIGGER.
7. Select the "PCM" on the NGS display and press TRIGGER.
8. Select the "VS" on the NGS display and press START.
9. The FREQUENCY METER screen will be displayed.

Note: The selected threshold voltage indicated on the FREQUENCY METER SCREEN should be 2 VOLTS DC. If an incorrect threshold voltage is selected, the calculated frequency value will be incorrect.

- Threshold voltage should be in the DC range. Press AC/DC key to select DC range.











10. Inspect frequency value and VSS PID.
11. Press LEVEL key to change the threshold voltage to 6 VOLTS.
12. Make sure that the FREQUENCY indicates 0 Hz.
- If FREQUENCY value is out of specifications, perform the "Open or short circuit inspection" below and repair or replace parts as necessary.

Power Supply Voltage Inspection
1. Disconnect the VSS connector.
2. Turn the ignition switch to ON.





3. Measure voltage at VSS connector terminal B (wiring harness side).
Specification
4.5 - 5.5 V
- If voltage is okay, go to "Open Circuit Inspection" and "Short Circuit Inspection".
- If voltage is wrong, repair wiring harness between VSS and PCM.

Open Circuit Inspection
1. Inspect the following circuit for open.
- Power circuit (VSS connector terminal A to main relay terminal D)
- Ground circuit (VSS connector terminal C to GND)
- If an open circuit or short circuit is found, repair the malfunctioning wiring harness.
- If there are no open or short circuits, perform the sensor rotor inspection. (See Sensor Rotor Inspection.)

Short Circuit Inspection
1. Inspect the following circuit for short.
- Power circuit (VSS connector terminal A to main relay terminal D)
- If an open circuit or short circuit is found, repair the malfunctioning wiring harness.





- If there are no open or short circuits, perform the sensor rotor inspection. (See Sensor Rotor Inspection.)

Sensor Rotor Inspection
1. Remove the VSS.
2. Shift the selector lever to N position.
3. Inspect sensor rotor surface via VSS installation hole while rotating the front tire manually.
1. Is sensor rotor free of damage and cracks?
2. Is sensor rotor free of any metallic shavings or particles?
- If sensor rotor is okay, replace VSS.
- If there is a problem, clean or replace the sensor rotor.