2012 Mazda 5 L4-2.5LFACTORY OEM SERVICE PROCEDURE

Vehicle Speed Sensor: Testing and Inspection





VEHICLE SPEED SENSOR (VSS) INSPECTION [FS5A-EL]

CAUTION:
- Do not allow foreign material or water to penetrate the connector. Otherwise, it could cause poor contact and corrosion.

On-Vehicle Inspection

1. Remove the aerodynamic under cover. Service and Repair

2. Inspect the VSS power supply circuit.
a. Remove the insulator from the transaxle.

Factory service manual diagram





b. Disconnect the VSS connector.

Factory service manual diagram





c. Switch the ignition ON.

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

Factory service manual diagram





- If there is any malfunction in the voltage, repair or replace the power supply circuit wiring harness.

Voltage
- B+

e. Switch the ignition OFF.

f. Connect the VSS connector.

3. Inspect the VSS GND circuit.
a. Switch the ignition OFF.

b. Measure the voltage at VSS terminal C.

Factory service manual diagram





- If there is any malfunction in the voltage, repair or replace the GND circuit wiring harness.

Voltage
- 1.0 V or less

4. Inspect the VSS signal circuit.
a. Connect the oscilloscope tester lead to the TCM and perform the oscilloscope setting.

- Terminal: TCM Z (+)-GND (-)
- Oscilloscope setting: 1 V/DIV (Y), 2 ms/DIV (X), DC range

b. Start the engine.

c. When all of the following conditions are met, measure the generated pulse.

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

Factory service manual diagram




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

Factory Service Tools

Use the Manual With the Right Hardware

Pair factory procedures with proven DIY tools so the instructions are easier to execute.

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.

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