Engine Control System Operation Inspection: VSS

Fig 1: Circuit Diagram - VSS

Courtesy of MAZDA MOTORS CORP.

1. Measure the #1 PCM terminal voltage and confirm that it is at 0 V  or 5 V  when the ignition switch at ON and the engine at idle.
   • If it is at 0 V  or 5 V,  intermittent concern exists. (See INTERMITTENT CONCERN TROUBLESHOOTING .)
   • If not, inspect the following points concerning the PCM connector.
   • If there is no problem, inspect for the following:
     • Female terminal opening is loose.
     • Coupler (pin holder) damage
     • Pin discoloration (blackness)
     • Harness/pin crimp is loose or disconnected.
2. Measure the #2 sensor terminal voltage and confirm that it is at 0 V  or 5 V  when the ignition switch at ON and the engine at idle.
   • If it is at 0 V  or 5 V  , intermittent concern exists. (See INTERMITTENT CONCERN TROUBLESHOOTING .)
   • If not, inspect the following points concerning the sensor connector:
   • If there is no problem, inspect for the following.
     • Female terminal opening is loose.
     • Coupler (pin holder) damage
     • Pin discoloration (blackness)
     • Harness/pin crimp is loose or disconnected.
3. Confirm that the #3 terminal switch voltage is at 0 V  .
   • If it is at 0 V  , inspect the sensor. If necessary, replace the sensor.
     • If necessary, replace the sensor.
   • If not, inspect for the following:
     • Open circuit in harness
     • Female terminal opening is loose.
     • Coupler (pin holder) damage
     • Pin discoloration (blackness)
     • Harness/pin crimp is loose or disconnected.