LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Mazda >> 2003 >> B2300 SE >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics >> System Tests >> Ignition Scope Check
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Ignition Scope Check

CAUTION: Fouled plugs or a damaged ignition may cause high catalyst temperatures. Check components next to catalyst and muffler for heat damage.
  1. Visual Inspection Of Ignition System -  Visually inspect the engine compartment to make sure all coils and spark plug wires are properly and securely connected. Examine 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. Complete FUEL OR MISFIRE MONITOR REPAIR VERIFICATION DRIVE CYCLE  under MONITOR REPAIR VERIFICATION DRIVE CYCLES under DRIVE CYCLE PROCEDURES. If a problem is not indicated, for diagnosis with engine analyzer, go to next step. For diagnosis without engine analyzer, go to step  10 .
    2. NOTE: In order for diagnostic procedures to provide accurate results, it is essential that 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 Spark Tester (303-D037) or equivalent to a properly operating ignition system and measuring firing voltage of spark tester only. Spark tester firing voltage should be approximately 28 kilovolts.
  2. Connect Engine Analyzer -  Obtain Engine Analyzer (010-01060) or an equivalent to diagnose concerns in secondary side of ignition system. After engine analyzer is connected to vehicle, go to next step.
  3. Check For Ignition Pattern -  Observe pattern on scope while cranking engine. Refer to Fig 1 . If pattern is flat, which indicates no spark on all cylinders, turn ignition off. Check condition of related fuses/fuse links. If okay, repair open circuit. If fuse/fuse link is damaged, check IGN START/RUN circuit for short to ground. Repair as necessary. Complete FUEL OR MISFIRE MONITOR REPAIR VERIFICATION DRIVE CYCLE  under MONITOR REPAIR VERIFICATION DRIVE CYCLES under DRIVE CYCLE PROCEDURES. If pattern is not flat, go to next step.
    Fig 1: Identifying Engine Analyzer "No Spark" Pattern
    G00159011Courtesy of MAZDA MOTORS CORP.
    4. 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. More than 2000 RPM, spark plugs are fired once per firing.
    Fig 2: Identifying Engine Analyzer "Normal" Pattern
    G00159012Courtesy of MAZDA MOTORS CORP.
  4. Check For Normal Ignition Pattern -  With KOER, check spark plug firing voltage average and evenness of patterns. Refer to Fig 2 . If patterns are even and average value of spark plug firing voltage is 20 kilovolts or more with evenness of spark plug firing voltage within 8 kilovolts 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  6 of NO START testing under SYSTEM TESTS, return to step  7 of NO START testing under SYSTEM TESTS.
    • All others, go to INTERMITTENT  testing under SYSTEM TESTS.
    If ignition pattern and values are not normal as specified, go to next step.
  5. Check For Two Missing Spark Patterns On The Same Coil -  Observe scope pattern. Refer to Fig 3 . If spark pattern is missing from two cylinders on same coil, proceed as follows:
    • Inspect spark plug wires and spark plugs for missing cylinders.
    • Measure resistance of spark plug wires. Replace wire(s) if resistance reading is more than 7000 ohms per foot.
    • Measure resistance of spark plugs. Replace spark plugs if resistance reading is less than 2000 ohms or more than 20,000 ohms.
    • If spark plug wires and spark plugs are OK, go to DTC P0350: IGNITION COIL CIRCUIT MALFUNCTION  under DIAGNOSTIC TESTS.
    If spark pattern is not missing from two cylinders on same coil, go to next step.
    Fig 3: Identifying Engine Analyzer "Two Missing Sparks" Pattern
    G00159009Courtesy of MAZDA MOTORS CORP.
  6. Check For One Missing Spark Pattern -  Observe scope pattern. Refer to Fig 4 . If spark pattern is missing from one cylinder, proceed as follows:
    • Inspect spark plug wire and spark plug for missing cylinder.
    • Measure resistance of spark plug wire. Replace wire if resistance reading is more than 7000 ohms per foot.
    • Measure resistance of spark plugs. Replace if resistance reading is less than 2000 ohms or more than 20,000 ohms.
    Complete FUEL OR MISFIRE MONITOR REPAIR VERIFICATION DRIVE CYCLE  under MONITOR REPAIR VERIFICATION DRIVE CYCLES under DRIVE CYCLE PROCEDURES. If spark pattern is not missing, go to next step.
    Fig 4: Identifying Engine Analyzer "One Missing Spark" Pattern
    G00159013Courtesy of MAZDA MOTORS CORP.
  7. Check For High Spark Plug Firing Voltage -  Check spark plug firing voltage average and evenness. Refer to Fig 5 . If average value of spark plug firing voltage is more than 20 kilovolts with evenness of spark plug voltage within 8 kilovolts or less, conditions affect all cylinders. Proceed as follows:
    • Inspect spark plug wires and spark plugs.
    • Measure resistance of spark plug wires. Replace if resistance reading is more than 7000 ohms per foot.
    • Measure resistance of spark plugs. Replace if resistance reading is less than 2000 ohms or more than 20,000 ohms.
    Complete FUEL OR MISFIRE MONITOR REPAIR VERIFICATION DRIVE CYCLE  under MONITOR REPAIR VERIFICATION DRIVE CYCLES under DRIVE CYCLE PROCEDURES. If spark pattern is not as specified, go to next step.
    Fig 5: Identifying Engine Analyzer "High Firing Voltage" Pattern
    G00159006Courtesy of MAZDA MOTORS CORP.
  8. Check For Low Spark Plug Firing Voltage -  Check spark plug firing voltage average and evenness. Refer to Fig 6 . If there is consistently low spark plug firing voltage or sloping spark line on one or more cylinders, proceed as follows:
    • Inspect spark plug wires and spark plugs.
    • Measure resistance of spark plug wires. Replace if resistance reading is more than 7000 ohms per foot.
    • Measure resistance of spark plugs. Replace if resistance reading is less than 2000 ohms or more than 20,000 ohms.
    Complete FUEL OR MISFIRE MONITOR REPAIR VERIFICATION DRIVE CYCLE  under MONITOR REPAIR VERIFICATION DRIVE CYCLES under DRIVE CYCLE PROCEDURES. If spark pattern is not as specified, go to next step.
    Fig 6: Identifying Engine Analyzer "Low Firing Voltage" Pattern
    G00159007Courtesy of MAZDA MOTORS CORP.
  9. Check For Evenness Between Cylinders -  Check spark plug firing voltage average and evenness. Refer to Fig 7 . If evenness of spark plug firing voltage is more than 8 kilovolts, proceed as follows:
    • Inspect spark plug wires and spark plugs.
    • Measure resistance of spark plug wires. Replace if resistance reading is more than 7000 ohms per foot.
    • Measure resistance of spark plugs. Replace if resistance reading is less than 2000 ohms or more than 20,000 ohms.

    Complete FUEL OR MISFIRE MONITOR REPAIR VERIFICATION DRIVE CYCLE  under MONITOR REPAIR VERIFICATION DRIVE CYCLES under DRIVE CYCLE PROCEDURES. If spark pattern is not as specified, go to next step.

    Fig 7: Identifying Engine Analyzer "Uneven Firing Voltage" Pattern
    G00159008Courtesy of MAZDA MOTORS CORP.
  10. DTC P0301-P0306: MISFIRE ON CYLINDERS 1-6 -  If any misfire DTCs are present, go to next step. If misfire DTCs are not present, go to step  12 .
  11. Check For Spark At Cylinder(s) Indicated By DTC(s) -  Disable Inertia Fuel Shutoff (IFS) switch. Disconnect spark plug wire from each spark plug. Connect Spark Tester (303-D037 or D81P-6666-A) or equivalent to spark plug wire. Check for spark while cranking engine. If Bluish-White spark is present, turn ignition off and go to step  13 . If Bluish-White spark is not present, turn ignition off and proceed as follows:
    • Inspect spark plug wires.
    • Measure resistance of spark plug wires. Replace if resistance reading is more than 7000 ohms per foot.
    Complete FUEL OR MISFIRE MONITOR REPAIR VERIFICATION DRIVE CYCLE  under MONITOR REPAIR VERIFICATION DRIVE CYCLES under DRIVE CYCLE PROCEDURES. If spark plug wires are okay, see INTERMITTENT  testing.
  12. Check For Spark At All Cylinders -  Disable Inertia Fuel Shutoff (IFS) switch. Disconnect spark plug wire from each spark plug. Connect Spark Tester (303-D037 or D81P-6666-A) or equivalent to spark plug wire. Check for spark while cranking engine. If Bluish-White spark is present at all cylinders, turn ignition off and go to next step. If Bluish-White spark is not present at all cylinders, turn ignition off and proceed as follows:
    • Inspect spark plug wires.
    • Measure resistance of spark plug wires. Replace if resistance reading is more than 7000 ohms per foot.
    Complete FUEL OR MISFIRE MONITOR REPAIR VERIFICATION DRIVE CYCLE  under MONITOR REPAIR VERIFICATION DRIVE CYCLES under DRIVE CYCLE PROCEDURES. If spark plug wires are okay, see INTERMITTENT  testing.
  13. Check Spark Plugs -  Remove and check 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, adjust gap or replace as necessary. Complete FUEL OR MISFIRE MONITOR REPAIR VERIFICATION DRIVE CYCLE  under MONITOR REPAIR VERIFICATION DRIVE CYCLES under DRIVE CYCLE PROCEDURES.
  14. Measure Spark Plug Resistance -  Measure spark plug resistance. If resistance reading is 2000-20,000 ohms, 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  6 of NO START testing, return to step  7 of NO START testing.
    • All others, go to INTERMITTENT  testing.
    If resistance reading is not as specified, replace faulty spark plug. Complete FUEL OR MISFIRE MONITOR REPAIR VERIFICATION DRIVE CYCLE  under MONITOR REPAIR VERIFICATION DRIVE CYCLES under DRIVE CYCLE PROCEDURES.
scientia non olet · About LEMON Manuals