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Home >> Chevrolet >> 2001 >> Venture Base, Van Passenger >> Repair and Diagnosis >> External Pages >> Different car >> Section 74 (Engine Controls - Self-Diagnostics) >> Diagnostic Tests >> DTC P0301-P0304: Cylinders No. 1-4 Misfire Detected >> Diagnostic Procedures

Diagnostic Procedures

WARNING: This page is about a different car, the 2002 Saturn LW200, 2002 Saturn L200, and 2002 Saturn L100. However, it is still accessible from the selected car via links, so may be relevant.
  1. Connect scan tool. Operate engine for one minute while using scan tool to monitor MISFIRE CURRENT CYLS. #1-4. If a specific cylinder misfire counter is dominant, go to step  3 . If a specific cylinder misfire counter is not dominant, go to next step.
  2. If random or paired cylinder misfire counters are dominant, see DTC P0300: ENGINE MISFIRE DETECTED  . If random or paired cylinder misfire counters are not dominant, see DIAGNOSTIC AIDS  .
  3. Using scan tool, monitor CALC COMPRESSION OUTPUT. If pattern is consistently stable at 00000110 or 00001001 with engine running, go to step  6 . If pattern is not stable at 00000110 or 00001001 with engine running, go to next step.
  4. Turn ignition off. Remove ignition coil housing. Check boot and spring of suspect cylinder. Replace as necessary. If boot and spring are okay, go to next step.
  5. Remove spark plug. Ensure spark plug gap is 0.045" (1.1 mm). Replace as necessary. If spark plug is okay, perform compression test. Compression should not be less than 100 psi. If compression is okay, replace spark plug. If compression is low, repair internal engine failure.
  6. Turn ignition on, engine off. Perform injector balance test. If pressure drop is within 1.5 psi (10 kPa), misfiring cylinder is flooded or spark plug is fouled. If pressure drop is not within 1.5 psi (10 kPa), go to next step.
  7. Using DVOM, measure fuel injector resistance on misfiring cylinder. If resistance is 12-13 ohms, clean fuel system and/or replace injector. Retest engine for misfire. If resistance is not 12-13 ohms, replace fuel injector.
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