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Home >> Oldsmobile >> 1997 >> Regency >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control Systems Tests W/Codes >> Diagnostic Trouble Codes >> DTC P1554 - Cruise Control Status Circuit >> Diagnostic Procedures
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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. Go to next step.
  2. Turn ignition on. Using scan tool, read CRUISE ENGAGED status. If scan tool displays YES, go to next step. If scan tool does not display YES, go to step 5).
  3. Turn ignition off. Disconnect PCM. Turn ignition on. Using a DVOM, check voltage between engine ground and cruise status circuit at PCM. If voltage reading is greater than 7 volts, go to next step. If voltage reading is not greater than 7 volts, go to step 9).
  4. Check for faulty cruise status circuit connection at PCM. If faulty connection is found, repair as necessary. After repairs, go to step 14). If connection is okay, go to step 12).
  5. Turn ignition of. Disconnect Stepper Motor Cruise Control (SMCC) module connector. Turn ignition on. Connect a test light between engine ground and SMCC harness connector cruise inhibit circuit. If test light illuminates, go to next step. If test light does not illuminate, go to step 7).
  6. Turn ignition off. Disconnect PCM connectors. Connect test light between battery voltage and SMCC harness connector cruise inhibit circuit. If test light illuminates, go to step 13). If test light does not illuminate, go to step 12).
  7. Turn ignition off. Reconnect SMCC harness connector. Disconnect PCM harness connectors. Turn ignition on. Using a DVOM, check voltage between engine ground and PCM harness connector cruise inhibit circuit. If DVOM voltage is 9-16 volts, go to next step. If voltage is not as specified, go to step 11).
  8. Clear DTCs. Start engine and read DTCs. If DTC P1554 resets, go to step 12). If DTC does not reset, see DIAGNOSTIC AIDS.
  9. Check cruise status circuit for open or short to ground. If a problem is found, repair as necessary and go to step 14). If no problem is found, go to next step.
  10. Check cruise status circuit for faulty connection at SMCC module. If faulty connection is found, repair as necessary. After repairs, go to step 14). If connection is okay, go to next step.
  11. Replace SMCC module. After replacing module, go to step 14).
  12. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to step 14).
  13. Locate and repair short to ground in cruise inhibit circuit. After repairs, go to next step.
  14. Clear DTCs. Start engine and read DTCs. If DTC P1554 resets, return to step 2). If DTC does not reset, repair is complete.
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