Subaru Coupes/Sedans/Wagons 1985-1996 Repair Guide

Vehicle Speed Sensor (VSS)

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OPERATION



The VSS consists of a magnetic rotor which is rotated by the speedometer cable and a reed switch. Rotation of the magnet rotor pulses the reed switch OFF/ON to produce a digital signal. The signal is used as a vehicle speed coefficient in ECU calculation.

The Impreza has 2 Vehicle Speed Sensors (VSS): VSS1 is located on the right side of the transaxle case housing; VSS2 is located in the combination meter assembly.

The Legacy has 2 Vehicle Speed Sensors (VSS): VSS1 is located inside of the transaxle; VSS2 is located in the combination meter assembly.

The SVX has 2 Vehicle Speed Sensors (VSS): VSS1 is located on the right side of the transaxle case; VSS2 is located on the right side of the torque converter case. The VSS1 detects rear wheel speed and the VSS2 detects front wheel speed.

TESTING



Justy and Loyale
  1. Switch the ignition ON and check the voltage on VSS terminal 29 of the ECU.
  2.  
  3. The voltage should vary above and below 2 volts with the vehicle moving slowly.

    If the voltage varies above and below 2 volts, the VSS is functioning.
     
    If there is no response, check for VSS signal at the rear of the instrument panel. If no VSS signal is present, replace the VSS. If VSS signal is present at the instrument panel, repair the harness.
     

  4.  

Impreza
VSS1
  1. Disconnect the electrical harness from the transaxle.
  2.  
  3. Connect an ohmmeter across the transaxle's electrical harness terminals 9 and 16.
  4.  
  5. The resistance should be 450-650 ohms.
  6.  
  7. After testing, reconnect the electrical harness.
  8.  

VSS2
  1. Remove the instrument cluster from the instrument panel.
  2.  
  3. Disconnect the electrical harnesses and the speedometer cable from the instrument cluster.
  4.  
  5. Connect an ohmmeter or continuity tester across the combination meter terminals 8 and 15.
  6.  
  7. Insert a small screwdriver in the speedometer cable drive socket.
  8.  
  9. Rotate the speedometer drive and note the continuity across the VSS terminal. Continuity should turn ON/OFF 4 times per speedometer drive revolution.
  10.  

Legacy
VSS1
  1. Disconnect the electrical harness from the transaxle.
  2.  
  3. Connect an ohmmeter across the transaxle's electrical harness terminals 9 and 16.
  4.  
  5. The resistance should be 450-650 ohms.
  6.  
  7. After testing, reconnect the electrical harness.
  8.  

VSS2
  1. Remove the instrument cluster from the instrument panel.
  2.  
  3. Disconnect the electrical connectors and the speedometer cable from the instrument cluster.
  4.  
  5. Connect an ohmmeter or continuity tester across the combination meter terminals 7 and 11.
  6.  
  7. Insert a small screwdriver in the speedometer cable drive socket.
  8.  
  9. Rotate the speedometer drive and note the continuity across the VSS terminal. Continuity should turn ON/OFF 4 times per speedometer drive revolution.
  10.  

SVX

See Figure 1

Click image to see an enlarged view

Fig. Fig. 1: Vehicle speed sensor terminal identification-SVX

VSS1
  1. Disconnect the electrical harness from the transaxle.
  2.  
  3. Connect an ohmmeter across the transaxle's electrical harness terminals 6 and 13.
  4.  
  5. The resistance should be 450-650 ohms.
  6.  
  7. After testing, reconnect the electrical harness.
  8.  

VSS2
  1. Remove the VSS from the vehicle.
  2.  
  3. Connect the VSS harness to the VSS. Backprobe the harness side of VSS connector terminals with a high-impedance voltmeter.
  4.  
  5. Turn the VSS gear by hand. The voltmeter should show 0-5 volts switching ON/OFF 4 times per revolution.
  6.  
  7. If there is no response, check the electrical connections, the ECU VSS signal terminal connection, the voltmeter setting and the harness. If all these items check out OK, replace the VSS.
  8.  

REMOVAL & INSTALLATION



Justy and Loyale

The VSS is inside the meter assembly. The speedometer should be replaced if the VSS is found to be defective.

Impreza
VSS1

The VSS1 is located inside the transaxle; no removal and installation is possible.

VSS2

The VSS2 is inside the meter assembly. The speedometer should be replaced if the VSS is found to be defective.

Legacy
VSS1
  1. Disconnect the negative battery cable.
  2.  
  3. Raise and safely support the vehicle on jackstands.
  4.  
  5. At the transaxle case, disconnect the electrical harness from the VSS1.
  6.  
  7. Remove the VSS-to-case bolt and the VSS.
  8.  

To install:
  1. Install the VSS, and tighten the bolt snugly.
  2.  
  3. Attach the harness to the VSS.
  4.  
  5. Connect the negative battery cable.
  6.  

VSS2

The VSS2 is inside the meter assembly. The speedometer should be replaced if the VSS is found to be defective.

SVX
VSS1
  1. Disconnect the negative battery cable.
  2.  
  3. Raise and safely support the vehicle on jackstands.
  4.  
  5. At the transaxle case, disconnect the electrical harness from the VSS1.
  6.  
  7. Remove the VSS-to-case bolt and the VSS.
  8.  

To install:
  1. Install VSS, and tighten the bolt snugly.
  2.  
  3. Attach the harness to the VSS.
  4.  
  5. Connect the negative battery cable.
  6.  

VSS2
  1. Disconnect the negative battery cable.
  2.  
  3. Disconnect the electrical harness from the VSS2.
  4.  
  5. Pull the VSS from the torque converter case.
  6.  

To install:
  1. Install VSS into the torque converter case.
  2.  
  3. Attach the wire harness to the sensor.
  4.  
  5. Connect the negative battery cable.
  6.  

 
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