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Code 22 - Oxygen Feedback System Test

  1. Turn ignition switch off. Connect a voltmeter to Green oxygen solenoid wire at carburetor 6-wire connector and ground. Disconnect and plug vacuum line at computer. Connect auxiliary vacuum supply to computer and apply 14 in. Hg vacuum.
  2. Connect a tachometer to engine. Disconnect oxygen system test connector and then reconnect Green/White wire only. If equipped with manual transaxle, disconnect speed sensor connector. Stick a straight pin into wire from cavity No. 5 of computer 10-wire connector.
  3. Connect a jumper wire between straight pin and White/Orange tracer wire of speed sensor harness connector. Start engine and wait 1 minute. Raise engine speed to 2000 RPM. Hold oxygen system test connector (open terminal) with one hand and touch battery positive terminal with other hand. If voltmeter reading drops to zero volts, go to step 4). If voltage does not decrease, go to step 6).
  4. With voltmeter connected to oxygen solenoid Green wire, disconnect and plug vacuum line at computer. Apply 14 in. Hg of vacuum to computer. Connect tachometer to engine and run engine to 2000 RPM.
  5. Reconnect oxygen test connector. Wait a few seconds for oxygen system to start working. If voltmeter reading pulsates between 7 and 14 volts, go to step 6). If voltage is below 7 volts, go to step 7).
  6. Connect voltmeter to oxygen solenoid Green wire. Disconnect and plug vacuum line to computer. Apply 14 in. Hg of vacuum to computer. Connect tachometer to engine and raise engine speed to 2000 RPM. Disconnect oxygen test connector. If voltmeter reading drops to zero volt, oxygen system is okay. If voltage does not decrease, check oxygen sensor wire for an open circuit to test connector. Repair as needed. If there is no open circuit, replace oxygen sensor.
  7. Run engine at 2000 RPM with 14 in. Hg of vacuum applied to computer. Disconnect hose from PCV valve and cover orifice. Allow air to slowly enter orifice. If voltmeter reading increases towards 14 volts, oxygen system is okay. If voltage does not increase, check oxygen sensor wire for a short circuit to test connector and repair as needed. If there is no short, replace oxygen sensor.
  8. With oxygen system test connector still disconnected (Green/White wire reconnected, let engine return to idle speed and then turn off engine. Disconnect computer 14-wire connector. Connect ohmmeter between test connector (Black wire) on computer side and cavity No. 10 of 14-wire connector. If ohmmeter shows continuity, replace computer. If there is no continuity, repair open wire to test connector.
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