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Home >> Buick >> 2002 >> Century Limited >> Repair and Diagnosis >> Engine Performance >> Testing & Diagnosis >> Engine Control System - Basic Diagnostic Procedures >> No-Start Diagnosis >> No Start - Engine Cranks Okay (3.1L & 3.4L) >> Fuel Injector Circuit Diagnosis (3.1L & 3.4L)

Fuel Injector Circuit Diagnosis (3.1L & 3.4L)

  1. If diagnostic system check has already been performed, go to next step. If diagnostic system check has not been performed, go to DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS in appropriate SELF-DIAGNOSTICS article.
  2. Are any injector DTCs set? If yes, diagnose using DTC P0201-P0206 diagnostic procedure. See appropriate SELF-DIAGNOSTICS article. If no, go to next step.
  3. Inspect fuel injector fuse. Is fuse open? If yes, go to next step. If no, go to step  6.
  4. Turn ignition off. Disconnect multi-way harness connector of the fuel injectors. Using a test light connected to battery voltage, probe the ignition 1 voltage circuit of the fuel injector (fuse side). Does test light illuminate? If yes, go to step  9. If no, go to next step.
  5. Turn ignition on, with engine off. Does test light illuminate? If yes, go to step  13. If no, go to step  8.
  6. Turn ignition off. Disconnect the fuel injector multi-way harness connector. Turn ignition on, with engine off. Probe the ignition 1 voltage circuit of the fuel injector, fuse side, with a test light connected to a known-good ground. Does test light illuminate? If yes, go to next step. If no, go to step  10.
  7. Using a DVOM, check resistance between the ignition voltage terminal and fuel injector harness connector terminal at the multi-way harness connector. If resistance is greater than 5 ohms, go to step  11. If no, go to step  12.
  8. Test the ignition 1 voltage circuit of the fuel injector, between the multi-way harness connector and fuel injectors for a short to ground. Did you find and correct the condition? If yes, go to step  14. If no, problem is intermittent.
  9. Repair short to ground in ignition voltage circuit of fuel injector. After repairs, go to step  14.
  10. Repair open in ignition 1 voltage between underhood fuse/relay block and multi-way connector. See WIRING DIAGRAMS article. After repairs, go to step  14.
  11. Repair the ignition 1 voltage circuit of the fuel injectors for an open and/or high resistance between the multi-way connector and splice. After repairs, go to step  14.
  12. Repair poor connection at the multi-way connector. After repairs, go to step  14.
  13. Repair short to a PCM ground in ignition voltage circuit of fuel injector. After repairs, go to next step.
  14. Operate the system in order to verify the repair. Did you correct the condition? If yes, system is okay. If no, go to step  3.
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