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Home >> Cadillac >> 2003 >> CTS Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - System & Component Testing >> Fuel Systems >> Fuel Injector Coil Test >> Diagnostic Procedure
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Diagnostic Procedure

  1. Perform Diagnostic System Check - Engine Controls. See DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - 3.2L CTS article. After performing Diagnostic System Check - Engine Controls, go to next step.
  2. Using scan tool, check Engine Coolant Temperature (ECT). Is the ECT value above 68°F (20°C)? If yes, go to next step. If no, go to step  4 .
  3. Disconnect fuel injector connector. Using DVOM, measure resistance of each fuel injector. Do any of the fuel injectors display a resistance outside 13-15.5 ohms? If yes, go to step  6 . If no, see DIAGNOSTIC AIDS  .
  4. Disconnect fuel injector multi-way harness connector. Using DVOM, measure resistance of each fuel injector between the ignition feed circuit and the fuel injector control circuit, at the multi-way connector. Record each fuel injector value. Subtract lowest resistance value from highest resistance value. Is the difference equal to, or less than, 3 ohms? If yes, see FUEL INJECTOR BALANCE TEST WITH SPECIAL TOOL  . If no, go to next step.
  5. Add all of the fuel injector resistance values, to obtain a total resistance value. Divide the total resistance value by the number of fuel injectors, to obtain an average resistance value. Subtract the lowest individual fuel injector resistance value from the average resistance value. Compare the difference between the highest individual fuel injector resistance valve and the average resistance value. Replace the fuel injector that displays the greatest resistance difference, above or below the average. See FUEL RAIL & INJECTORS under FUEL SYSTEMS in REMOVAL & INSTALLATION - CTS article. After repairs, go to step  7 .
  6. If resistance of fuel injector(s) is not 11-14 ohms, replace fuel injector(s). See FUEL RAIL & INJECTORS under FUEL SYSTEMS in REMOVAL & INSTALLATION - CTS article. After repairs, go to next step.
  7. Operate system in order to verify repair. Did you correct the condition? If yes, system is okay. If no, go to step  2 .
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