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Home >> Suzuki >> 2002 >> XL-7 Plus >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics >> Diagnostic Tests >> DTC P0300, DTC P0301, DTC P0302, DTC P0303, DTC P0304, DTC P0305 Or DTC P0306 >> Diagnosis & Repair Procedure
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Diagnosis & Repair Procedure

  1. If engine system check has been performed, go to next step. If engine system check has not been performed, go to A4: ENGINE SYSTEM CHECK  under SYSTEM TESTS.
  2. Remove spark plugs and check gap. Gap should be .028-.031 in. (.7-.8 mm). Check for carbon deposits or cracked insulators. Ensure correct spark plugs are installed. If problem is found, repair or replace as necessary. After repair, repeat DTC CONFIRMATION TEST . Disconnect all fuel injector harness 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 ignition system components. See IGNITION CHECKS in BASIC DIAGNOSTIC PROCEDURES article.
  3. Check fuel pressure. See FUEL SYSTEM in BASIC DIAGNOSTIC PROCEDURES article. Fuel pressure should be 38-44 psi (2.7-3.1 kg/cm2 ) with key on and engine off, and 28-34 psi (2.0-2.4 kg/cm2 ) with engine running at idle. If fuel pressure is as specified, go to next step. If fuel pressure is not as specified, go to FUEL SYSTEM in SYSTEM & COMPONENT TESTING article. If no problem is found, go to next step.
  4. Inspect fuel injectors and fuel system circuit. See FUEL INJECTORS under FUEL SYSTEM in SYSTEM & COMPONENT TESTING article. If problem is found, repair as necessary. After repair, repeat DTC CONFIRMATION TEST . If fuel system is okay, go to next step.
  5. Check ignition timing. See TIMING CONTROL SYSTEMS in BASIC DIAGNOSTIC PROCEDURES article. Adjust as necessary. After repair, repeat DTC CONFIRMATION TEST . If ignition timing is okay, go to next step.
  6. Check EGR system performance. See EXHAUST GAS RECIRCULATION under EMISSIONS SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING article. If problem is found, repair as necessary. After repair, repeat DTC CONFIRMATION TEST . If EGR system performance is okay, go to next step.
  7. Check fuel level sensor performance. For testing procedure, go to DTC P0461 . If problem is found, repair as necessary. After repair, repeat DTC CONFIRMATION TEST . If fuel level sensor performance is okay, go to next step.
  8. Check engine compression. Engine compression should be a minimum of 156 psi (11 kg/cm2 ) at 250 RPM with a maximum variation of 14 psi. If engine compression is okay, check valve lash and valve timing. See appropriate article in ENGINES. If problem is found, repair as necessary. After repair, repeat DTC CONFIRMATION TEST . If compression tests okay, go to next step.
  9. Check ECM harness connections and grounds for corrosion or loose terminals. If problem is found, repair as necessary. After repair, repeat DTC CONFIRMATION TEST . If connections are okay, problem is probably intermittent. See INTERMITTENTS in TROUBLE SHOOTING - NO CODES article.
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