LEMON Manuals: Even more car manuals for everyone
Home >> Suzuki >> 2001 >> XL-7 Limited >> Repair and Diagnosis (Single Page) >> Engine Performance >> System >> Engine Controls - Self-Diagnostics >> Diagnostic Tests >> DTC P0300: Random Misfire, Or DTC P0301-P0306: Cylinders No. 1-6 Misfire >> Diagnosis & Repair Procedure

Diagnosis & Repair Procedure

  1. Perform DTC CONFIRMATION TEST . If DTC P0300, P0301, P0302, P0303, P0304, P0305 or P0306 is set, go to next step. If DTC P0300, P0301, P0302, P0303, P0304, P0305 or P0306 are not set, problem is intermittent. System is okay at this time. See TROUBLE SHOOTING - NO CODES article.
  2. Remove spark plugs and check for proper gap. Check for carbon deposits or cracked insulators. Repair as necessary. If spark plugs are okay, disconnect all injector connectors. Using a spark tester, ensure a strong, Blue spark is present at each plug wire. If a strong, Blue spark is present at each plug wire, reconnect injector harness connectors and go to next step. If no spark or a weak spark is present, check secondary ignition system components. See IGNITION CHECKS in BASIC DIAGNOSTIC PROCEDURES article.
  3. Using a mechanic's stethoscope, check each fuel injector for a clicking sound while cranking engine and with engine at idle. If sound is not heard from all 6 injectors, inspect and repair poor connections or open circuit between fuel injector(s) and PCM. If wiring and connections are okay, replace PCM and go to DTC CONFIRMATION TEST . If sound is heard from all 6 injectors, go to next step.
  4. Check fuel pressure. See CIRCUIT TEST B-3: FUEL PRESSURE INSPECTION under CIRCUIT TESTS in BASIC DIAGNOSTIC PROCEDURES article. Repair as necessary and go to DTC CONFIRMATION TEST . If fuel pressure is within specifications, go to next step.
  5. Check fuel injectors operation. See CIRCUIT TEST B-1: FUEL INJECTOR CIRCUIT INSPECTION under CIRCUIT TESTS in BASIC DIAGNOSTIC PROCEDURES article. Repair as necessary and go to DTC CONFIRMATION TEST . If fuel injectors are okay, go to next step.
  6. Check ignition timing. See IGNITION TIMING in ON-VEHICLE ADJUSTMENTS article. Adjust ignition timing as necessary and go to DTC CONFIRMATION TEST . If ignition timing is okay, go to next step.
  7. Check EGR system operation. See EXHAUST GAS RECIRCULATION (EGR) under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING article. Repair as necessary and go to DTC CONFIRMATION TEST . If EGR operation is okay, go to next step.
  8. Check fuel level sensor operation. See DTC P0461: FUEL LEVEL SENSOR CIRCUIT PERFORMANCE PROBLEM  test. Repair as necessary and go to DTC CONFIRMATION TEST . If fuel level sensor operation is okay, go to next step.
  9. Inspect engine mechanical systems for proper operation. Check engine compression, valve lash adjustment and valve timing. See appropriate article in ENGINES. Repair as necessary and go to DTC CONFIRMATION TEST . If engine mechanical condition is okay, check PCM, ignition and fuel system wiring harnesses for intermittent open or short circuits. Repair as necessary and go to DTC CONFIRMATION TEST .
scientia non olet · About LEMON Manuals