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Home >> Buick >> 2001 >> Century Limited >> Repair and Diagnosis (Single Page) >> Engine Performance >> Testing & Diagnosis >> Engine Controls Self-Diagnostics - 3.1L & 3.4L >> Diagnostic Tests >> DTC P1374: Crankshaft Position High-To-Low Resolution Frequency Correlation >> Diagnostic Procedure (Except Grand Prix)

Diagnostic Procedure (Except Grand Prix)

  1. Perform powertrain diagnostic system check. See POWERTRAIN DIAGNOSTIC SYSTEM CHECK . After performing powertrain diagnostic system check, go to next step.
  2. Attempt to start engine. If engine starts and runs, go to next step. If engine does not start and run, see appropriate BASIC DIAGNOSTIC PROCEDURES article.
  3. Using scan tool, observe FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Operate vehicle within conditions noted in FREEZE FRAME/FAILURE RECORDS data. If scan tool indicates that this DTC failed this ignition cycle, go to next step. If scan tool does not indicate that this DTC failed this ignition cycle, go to DIAGNOSTIC AIDS .
  4. Turn ignition off. Install Injector Harness Load Tester (J-34730-380) to multi-way injector harness connector. Disconnect IC module harness connector C1. Turn ignition on. Using a test light connected to battery positive, repeatedly probe IC module harness connector C1 terminal "E" (Purple/White wire) while observing injector harness load tester light. See Figure. If injector harness load tester light flashes, go to step  8. If injector harness load tester light does not flash, go to next step.
  5. Turn ignition off. Disconnect PCM harness connector. See PCM LOCATION . Turn ignition on. Check for open or short in low resolution engine speed signal circuit (Purple/White wire) between IC module harness connector C1 terminal "E" and PCM harness connector C1 terminal No. 8. See Figure or Figure . Repair circuit as necessary, then go to step  11. If circuit is okay, go to next step.
  6. Check for faulty low resolution engine speed signal circuit connection at PCM. If connection is faulty, repair as necessary. After repairs, go to step  11. If connection is okay, go to next step.
  7. Check for incorrect harness routing near secondary ignition components, ignition coil arcing to wiring harness or IC module. Check ignition coils for cracks, carbon tracking or other signs of damage. Check for secondary ignition wire(s) arcing to wiring harness. If a problem is found, repair as necessary. After repairs, go to step  11. If no problem is found, go to step  10.
  8. Check for faulty connections at IC module. If faulty connection is found, repair as necessary. After repairs, go to step  11. If connections are okay, go to next step.
  9. Replace IC module. After replacing IC module, go to step  11.
  10. Replace PCM. Program replacement PCM using required equipment. See PROGRAMMING . After replacing PCM, go to next step.
  11. Read and record FAILURE RECORDS data for this DTC. Operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, read SPECIFIC DTC. If scan tool indicates that this DTC FAILED THIS IGN, return to step  2. If scan tool does not indicate that this DTC FAILED THIS IGN, go to next step.
  12. Using scan tool, observe all stored information. If scan tool displays any DTCs that have not been diagnosed, diagnose those DTCs. See DIAGNOSTIC TROUBLE CODE DEFINITIONS . If scan tool does not display any DTCs, system is okay.
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