Mazda 3 Service Manual: Vehicle Speed Sensor (VSS) Inspection [FS5 A EL]

On-Vehicle Inspection

1. Inspect the power supply circuit for the VSS.

a. Remove the insulator from the transaxle.

b. Disconnect the VSS connector.

c. Switch the ignition to ON (engine off).

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

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

VSS specification

• B+

e. Switch the ignition to off.

f. 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 TCM connector terminals and set it as below.

• (+) lead: TCM terminal Z

• (-) lead: battery negative 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.

• Gear position: 3GR

• Vehicle speed: 30 km/h {19 mph}

• If there is any malfunction, replace the VSS..