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Home >> Oldsmobile >> 1997 >> Regency >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control Systems Tests W/Codes >> Diagnostic Trouble Codes >> DTC P1662 - Cruise Control Inhibit 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. 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 cruise inhibit driver circuit. If battery voltage is present, go to next step. If battery voltage is not present, go to step 6).
  3. Using DVOM in 10-amp scale, check current between engine ground and cruise inhibit driver circuit for 2 minutes. If current remains between .001 and 0.5 amp, go to step 11). If current does not remain as specified, go to next step.
  4. Turn ignition off. With PCM connectors disconnected, disconnect cruise inhibit connector. Turn ignition on. Using DVOM, check voltage between engine ground and Servo Motor Cruise Control (SMCC) module cruise inhibit 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 cruise inhibit driver circuit. After repairs, go to step 16).
  6. Check SMCC module 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 SMCC module ignition feed circuit. Replace fuse. After repairs, go to step 16).
  8. Disconnect SMCC module connector. Turn ignition on. Check voltage between engine ground and SMCC module ignition feed circuit. If battery voltage is present, go to next step. If battery voltage is not present, go to step 13).
  9. Check cruise inhibit 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 cruise inhibit driver and ignition feed circuits for faulty connection at SMCC module and PCM. If connection is faulty, 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 SMCC module connector. Turn ignition on. Connect a test light between SMCC module harness connector cruise inhibit driver and ignition feed circuits. Using scan tool, cycle cruise inhibit output on and off. If test light flashes on and off, see DIAGNOSTIC AIDS. If test light does not flash on and off, go to next step.
  12. Check cruise inhibit driver circuit for faulty connection at PCM. If connection is faulty, repair as necessary. After repairs, go to step 16). If connection is okay, go to step 15).
  13. Locate and repair open SMCC module ignition feed circuit. After repairs, go to step 16).
  14. Replace SMCC module. After replacing module, 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 P1662. If scan tool displays DTC P1662 FAILED THIS IGN, return to step 2). If scan tool does not display DTC P1662 FAILED THIS IGN, repair is complete.
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