Vehicle Speed Sensor: Testing and Inspection

VEHICLE SPEED SENSOR (VSS) INSPECTION [FN4A-EL]

CAUTION:
- Water or foreign objects entering the connector can cause a poor connection or corrosion. Be sure not to drop water or foreign objects on the connector when disconnecting it.

On-Vehicle Inspection

1. Inspect the power supply circuit for the VSS.
a. Disconnect the VSS connector.






b. Switch the ignition to ON.

c. Measure the voltage at VSS connector terminal A (harness side).






- If there is any malfunction, repair wiring harness between VSS and main relay.

VSS specification
- B+

d. Switch the ignition to off.

e. Connect the VSS connector.

2. Inspect the GND circuit for the VSS.
a. Switch the ignition to off.

b. Measure the voltage at VSS connector terminal C (harness side).






- If there is any malfunction, repair wiring harness between VSS and GND.

VSS specification
- Below 1.0 V

3. Inspect the signal circuit for the VSS.
a. Connect the oscilloscope to the following PCM connector terminals and set it as below.

- (+) lead: PCM terminal 1AX
- (-) lead: negative battery terminal (-)
- Oscilloscope setting: 1 V/DIV (Y), 2 ms/DIV (X), DC range

b. Start the engine.

c. Measure the wave form when the following conditions are met.

- Vehicle speed: 30 km/h {19 mph}
- Gear position: 3 GR





- If there is any malfunction, replace the VSS. Service and Repair