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Home >> Oldsmobile >> 1997 >> Regency >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control Systems Tests W/Codes >> Diagnostic Trouble Codes >> DTC P1654 - A/C Relay Control Circuit >> Diagnostic Procedures

Diagnostic Procedures

  1. Perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK. See the BASIC TESTING - 3.8L article. Read and record FREEZE FRAME and/or FAIL RECORDS data for each DTC set. After performing OBD system check, go to next step.
  2. Turn ignition off. Disconnect PCM connectors. Turn ignition on. Using a DVOM, check voltage between engine ground and PCM harness connector A/C relay driver circuit. If battery voltage is present, go to next step. If battery voltage is not present, go to step 6).
  3. Disconnect A/C clutch connector. Using DVOM in 10 amp scale, check current between engine ground and A/C relay driver circuit for 2 minutes. If current remains .05-0.5 amp, go to step 11). If current does not remain .05-0.5 amp, go to next step.
  4. Ignition off. Reconnect A/C clutch connector. With PCM connectors still disconnected, disconnect A/C relay connector. Ignition on. Using DVOM, check voltage between engine ground and A/C relay driver circuit. If voltage reading is zero volts, go to step 10). If voltage reading is greater than zero volts, go to next step.
  5. Locate and repair short to voltage in A/C relay driver circuit. After repairs, go to step 16).
  6. Check A/C relay ignition feed fuse. If fuse is blown, go to next step. If fuse is okay, go to step 8).
  7. Locate and repair short to ground in A/C relay ignition feed circuit. Replace fuse. After repairs, go to step 16).
  8. Disconnect A/C relay connector. Turn ignition on. Check voltage between engine ground and A/C relay ignition feed circuit. If voltage reading is 9-16 volts, go to next step. If voltage reading is not 9-16 volts, go to step 13).
  9. Check A/C relay driver circuit for open or short to ground. If a problem is found, repair as necessary. After repairs, go to step 16). If no problem is found, go to next step.
  10. Check A/C relay driver and ignition feed circuits for faulty connection at A/C relay and PCM. If faulty connection is found, repair as necessary. After repairs, go to step 16). If connection is okay, go to step 14).
  11. Turn ignition off. Reconnect PCM connectors. Disconnect A/C relay connector. Turn ignition on. Connect a test light between A/C relay harness connector A/C relay driver and ignition feed circuits. Using scan tool, cycle A/C relay on and off. If test light flashes on and off, go to DIAGNOSTIC AIDS. If test light does not flash on and off, go to next step.
  12. Check A/C relay driver circuit for faulty connection at PCM. If faulty connection is found, repair as necessary. After repairs, go to step 16). If connection is okay, go to step 15).
  13. Locate and repair open A/C relay ignition feed circuit. After repairs, go to step 16).
  14. Replace A/C relay. After replacing relay, go to step 16).
  15. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
  16. Using scan tool, read and record FAIL RECORDS DATA, and clear DTCs. Operate vehicle within conditions noted in FAIL RECORDS data. Using scan tool, select SPECIFIC DTC INFO for DTC P1654. If scan tool displays DTC P1654 FAILED THIS IGN, return to step 2). If scan tool does not display DTC P1654 FAILED THIS IGN, repair is complete.
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