Visual Inspection
1. Remove the VSS. (See VEHICLE SPEEDOMETER SENSOR (VSS) REMOVAL/INSTALLATION.)
2. Make sure that the sensor is free of any metallic shavings or particles.
3. Install the VSS. (See VEHICLE SPEEDOMETER SENSOR (VSS) REMOVAL/INSTALLATION.)
Wave profile Inspection
1. Remove the PCM. (See PCM REMOVAL/INSTALLATION.)
2. Connect WDS or equivalent to DLC connector.
3. Connect osilloscope test leads to the following PCM connector terminals.
4. Start the engine.
5. Monitor VSS PID.
6. Inspect wave profile.
- If wave profile or voltage are out of specifications, carry out the Open Circuit Inspection or Short Circuit Inspection

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

Open Circuit Inspection
Inspect the following circuit for open.
Short Circuit Inspection
Inspect the following circuit for short.

Sensor Rotor Inspection
1. Remove the VSS. (See VEHICLE SPEEDOMETER SENSOR (VSS) REMOVAL/INSTALLATION.)
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 the VSS.
- If there is a problem, clean or replace the sensor rotor.
Input/turbine speed sensor removal/installation
Vehicle speedometer sensor (vss) removal/installationMazda 6 Service Manual: Scheduled maintenance
SCHEDULED MAINTENANCE TABLE
For Europe (L.H.D. U.K.)
Chart symbols:
I : Inspect and repair, clean, adjust, or replace if necessary.
(Oil-permeated air cleaner elements cannot be cleaned using the air-blow
method.)
R : Replace
T : Tighten
L : Lubricate
Remarks:
To ensure efficient oper ...
Mazda 6 Service Manual: Pcv valve inspection
1. Disconnect the negative battery cable.
2. Remove the intake maniforld.(see INTAKE-AIR SYSTEM REMOVAL/INSTALLATION.)
3. Remove the PCV valve.
4. Blow through the valve and verify that air flows as specified.
If not as specified, replace the PCV valve.
Specification
...