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Home >> Mazda >> 2002 >> Tribute LX, 4WD >> Repair and Diagnosis >> External Pages >> Different car >> Section 48 (Engine Controls - Self-Diagnostics) >> Diagnostic Tests >> DTC P0350: Ignition Coil Circuit Malfunction >> Diagnostic Procedures

Diagnostic Procedures

WARNING: This page is about a different car, the 2002 Mazda B4000, 2002 Mazda B3000, and 2002 Mazda B2300. However, it is still accessible from the selected car via links, so may be relevant.
  1. If QUICK TEST was not performed, go to QUICK TEST  under SELF-DIAGNOSTIC SYSTEM. If QUICK TEST was performed, go to next step.

  2. Visual Inspection

    Visually inspect engine compartment to ensure all vacuum hoses and spark plug wires are properly routed and securely connected. Check all wiring harnesses and connectors for damaged, burned or overheated insulation and loose or broken conditions. Ensure battery is fully charged. All accessories must be off during diagnosis. If a problem is indicated, repair as necessary.
    NOTE: In order for diagnostic procedures to provide accurate results, it is essential that the calibration of the engine analyzer be maintained. Refer to equipment manual for procedure to calibrate engine analyzer. If equipment manual is not available, an estimate of the calibration can be made by connecting a Spark Tester (303-D037) to a properly operating ignition system and measuring the firing voltage of spark tester only. The spark tester firing voltage should be approximately 28KV.

  3. Connect Engine Analyzer

    Obtain Engine Analyzer (010-01060) or equivalent to diagnose concerns in secondary side of ignition system. After engine analyzer is connected to vehicle, go to next step.

  4. Check For Ignition Pattern

    Observe pattern on scope while cranking engine. If scope pattern indicates spark while cranking engine, go to next step. If scope pattern is flat (no spark) for all cylinders, a problem is present in IGN START/ON (RUN) circuit. Turn ignition off. Check fuse No. 19 in instrument panel fuse panel. If fuse is okay, repair open circuit. See WIRING DIAGRAMS article. If fuse is open, check IGN START/ON (RUN) circuit for short to ground. Repair as necessary. See WIRING DIAGRAMS article. Go to step  12 .
    NOTE: Spark plugs are fired up to four strikes per firing. Multi-strike operating mode is dependent on PCM calibration and is limited to less than 2000 RPM. Above 2000 RPM, spark plugs are fired once per firing.

  5. Check For Normal Ignition Pattern

    With KOER, check spark plug firing voltage average and evenness of patterns. If all patterns are NOT even with an average spark plug firing voltage of 20KV or more, with evenness of spark plug firing voltage of 8KV or less, go to step  6 . If all patterns are even with an average spark plug firing voltage of 20KV or more, with evenness of spark plug firing voltage of 8KV or less, proceed as follows:
    • If directed here from TROUBLE SHOOTING - NO CODES article, return to SYMPTOM DIAGNOSIS in TROUBLE SHOOTING - NO CODES article.
    • If directed here from step  5 of IGNITION SCOPE CHECK under SYSTEM TESTS, return to step  11 of IGNITION SCOPE CHECK  .
    • All others, go to INTERMITTENT  under SYSTEM TESTS.

  6. Check Pattern On Scope

    Observe scope pattern for anything unusual. If scope pattern appears normal, go to next step. If scope pattern does not appear normal, inspect spark plug wires and spark plugs. Measure resistance of spark plug wires. Replace spark plug wires if resistance is more than 7000 ohms per foot. Check spark plug gaps. Adjust as necessary. Measure resistance of spark plugs. Replace spark plugs if resistance is less than 2000 ohms or more than 20,000 ohms. Go to step  11 .

  7. DTCs P0301-P0306: Misfire On Cylinders 1-6

    If DTCs P0301-P0306 is set, go to next step. If DTC P0301-P0306 is not set, go to step  9 .

  8. Check For Spark At Cylinder(s) Indicated By DTC(s)

    Disable inertia fuel shutoff switch. Using a spark tester, check for spark at suspect cylinder while cranking engine. If spark is bluish-white, turn ignition off. Go to step  10 . If spark is not bluish-white, turn ignition off. Inspect spark plug at suspect cylinder(s). Measure resistance of spark plug(s). Replace spark plugs if resistance is less than 2000 ohms or more than 20,000 ohms. Go to step  12 .

  9. Check For Spark At All Cylinders

    Disable fuel inertia fuel shutoff switch. Using a spark tester, check for spark at each cylinder while cranking engine. If spark is bluish-white and consistent between all cylinders, turn ignition off. Go to next step. If spark is not bluish-white and not consistent between all cylinders, turn ignition off. Measure resistance of spark plug(s). Replace spark plugs if resistance is less than 2000 ohms or more than 20,000 ohms. Go to step  12 .

  10. Check Spark Plugs

    Remove and inspect spark plugs for damage, wear, carbon deposits and proper plug gap. If spark plugs are okay, go to next step. If spark plugs are not okay, repair or replace as necessary. Go to step  12 .

  11. Check Spark Plug Resistance

    Measure resistance of each spark plug. If resistance reading is less than 2000 ohms or more than 20,000 ohms, replace spark plug(s). Go to next step. If resistance reading is 2000-20,000 ohms, proceed as follows:

  12. Drive Cycle

    Reconnect all electrical connectors. Using scan tool, clear DTC memory. Perform FUEL OR MISFIRE MONITOR REPAIR VERIFICATION DRIVE CYCLE  in MONITOR REPAIR VERIFICATION DRIVE CYCLES under DRIVE CYCLE PROCEDURES. Using scan tool, retrieve DTCs. If same DTC is not present, go to next step. If same DTC is present, replace faulty PCM. Go to next step.

  13. Verify Trouble Shooting Of DTCs Completed

    Perform QUICK TEST  under SELF-DIAGNOSTIC SYSTEM. If any DTC is present, go to applicable procedure for other DTCs. See DIAGNOSTIC TROUBLE CODE DEFINITIONS  . If no DTCs are set, trouble shooting is complete.
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