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Code 28 - Speed Sensor System Test

  1. Turn ignition switch off. Remove speed sensor from transaxle. Disconnect speed sensor connector. Connect ohmmeter between terminals of speed sensor connector. Slowly rotate speed sensor 1 turn. Ohmmeter should show approximately 8 pulses for every turn of the speed sensor. If ohmmeter reading is okay, go to step 2). If not, replace speed sensor.
  2. Disconnect speed sensor connector. Connect positive lead of voltmeter to White/Orange wire of speed sensor connector. Connect negative lead of voltmeter to Black/Blue wire of speed sensor harness connector. Turn ignition to "RUN" position.
  3. Voltmeter should read at least 8.5 volts. If voltage is okay, inspect transaxle drive gear-to-speed sensor drive gear for proper contact. If zero volts, move voltmeter negative lead to a good engine ground. If voltmeter now reads correct voltage, inspect speed sensor ground wire for an open circuit and repair. If voltmeter still reads zero, go to step 4).
  4. Turn ignition switch off. Disconnect computer 14-wire connector. Connect ohmmeter between cavity No. 2 of 14-wire connector and White/Orange wire of speed sensor harness connector. If ohmmeter shows continuity, replace computer. If no continuity, inspect wire for open circuit and repair.
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