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Home >> Chevrolet >> 1998 >> Cavalier LS, 2.4 T >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System & Engine Component Tests - 2.4L >> Computerized Engine Controls >> Pcm Output Diagnosis
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Pcm Output Diagnosis

  1. If powertrain OBD system check has been performed, go to next step. If powertrain OBD system check has not been performed, perform powertrain OBD system check. See POWERTRAIN OBD SYSTEM CHECK in TESTS W/CODES - 2.4L article.
  2. Connect scan tool to data link connector. If a No. 1 is displayed below any of the number output drivers, go to next step. If a No. 1 is not displayed below any of the number output drivers, go to step 4).
  3. Check for an open or a short in any corresponding circuit that indicated a No. 1 below output driver. If open or short does not exist, go to step 8). If open or short exists, repair as necessary and go to step 10).
  4. Using scan tool, command output being checked while watching corresponding position for that circuit. If that circuits position does not change to a No. 1, go to next step. If that circuits position changes to a No. 1, go to step 7).
  5. If component or function does not operate when commanded, go to next step. If component or function operates when commanded, go to step 10).
  6. Make necessary repairs to component or component circuit as necessary and go to step 10).
  7. Repair short to voltage in corresponding circuit and go to step 10).
  8. Disconnect appropriate component harness connector. If No. 1 is still displayed below that component's numbered position, go to next step. If No. 1 is not still displayed below that components numbered position, go to step 6).
  9. Replace PCM and go to next step.
  10. Operate vehicle under condition under which original symptom was noted. If system does not operate properly, go to step 2).
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