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Home >> Buick >> 1996 >> Century Custom >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - Tests W/Codes - 3.1L >> Diagnostic Trouble Codes >> DTC P1350 - Ignition Control System >> Diagnostic Procedures
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Diagnostic Procedures

  1. Perform On-Board Diagnostic (OBD) System Check. After performing OBD system check, go to next step.
  2. Using scan tool, select CLEAR INFO or CLEAR DTCS function to clear DTC P1350. Start engine and allow it to idle for 2 minutes. Check for DTCs. If DTC P1350 is set, go to next step. If DTC P1350 is not set, see DIAGNOSTIC AIDS.
  3. Turn ignition off. Disconnect PCM connector. Turn ignition on. Using DVOM, measure resistance between IC circuit and reference low circuit terminals at PCM connector. If resistance is less than 300 ohms, go to step 6). If resistance is 300 ohms or greater, go to next step.
  4. Turn ignition off. Disconnect ICM connector. Check for an open IC circuit. Repair as necessary. After repair is completed, go to step 10). If circuit is okay, go to next step.
  5. Check IC circuit terminal for poor connection at ICM. Repair as necessary. After repair is completed, go to step 10). If connection is okay, go to step 8).
  6. Check IC circuit terminal for poor connection at PCM. Repair as necessary. After repair is completed, go to step 10). If connection is okay, go to next step.
  7. Replace PCM. Program replacement PCM using required equipment. After repair is completed, go to step 10).
  8. Turn ignition on. Check for a short to voltage in by-pass circuit between ICM and PCM. Repair as necessary. After repair is completed, go to step 10). If circuit is okay, go to next step.
  9. Replace ICM. After repair is completed, go to next step.
  10. Using scan tool, select CLEAR INFO or CLEAR DTCS function to clear DTCs. Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME data and note parameters. Start engine and operate vehicle within conditions required for setting this DTC, and as close to conditions recorded in FREEZE FRAME as possible. Monitor SPECIFIC DTC info for DTC P1350 until DTC P1350 test runs. If scan tool indicates FAILED THIS IGN, repeat step 2). If scan tool does not indicate FAILED THIS IGN, repair is complete.
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