2003 Mazda 6 s, AutomaticFACTORY OEM SERVICE PROCEDURE

Spark Test

Disconnect the fuel pump relay. Verify that each high-tension lead and connector is connected properly. Inspect ignition system using following procedure:

  1. Disconnect ignition coil from spark plugs. Remove spark plugs. Reconnect spark plug to ignition coil. Ground spark plug to engine. If strong blue spark is visible at each cylinder while cranking, ignition system is okay. If strong blue spark is not visible at some cylinders, go to next step. If strong blue spark is not visible at all cylinders, go to step  4.
  2. 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 faulty, replace spark plugs. After repair, repeat step  1.
  3. Inspect following wiring harnesses for open or short circuit:
    • Ignition coil No. 1 harness connector terminal "B" (White wire) to PCM 104-pin harness connector terminal No. 26 (Black wire)
    • Ignition coil No. 2 harness connector terminal "B" (Blue wire) to PCM 104-pin harness connector terminal No. 52 (Blue wire)
    • Ignition coil No. 3 harness connector terminal "B" (Yellow wire) to PCM 104-pin harness connector terminal No. 78 (Green wire)
    • Ignition coil No. 4 harness connector terminal "B" (Orange wire) to PCM 104-pin harness connector terminal No. 1 (White wire)
    • Ignition coil No. 5 harness connector terminal "B" (Black wire) to PCM 104-pin harness connector terminal No. 27 (Yellow wire)
    • Ignition coil No. 6 harness connector terminal "B" (Green/Yellow wire) to PCM 104-pin harness connector terminal No. 82 (Red wire)
    If all wiring harnesses are okay, inspect suspected ignition coil. Refer to IGNITION COILS under IGNITION SYSTEM in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If any wire harnesses are faulty, repair suspected wire or replace wire harness. After repair, repeat step  1.
  4. Measure voltage at harness connector terminal "A" of each ignition coil. If battery voltage is present, go to next step. If battery voltage is not present, check power supply circuit of suspected ignition coil.
  5. If PCM connector or ignition coil connectors do not have a poor connection, go to next step. If PCM connector or ignition coil connectors have a poor connection, repair or replace terminal or replace connector. After repair, repeat step  1.
    • Check Crankshaft Position (CKP) sensor and crankshaft pulley.
    • Measure voltage at PCM terminal No. 21 or 22. Voltage reading should be about 1.5 volts.
    If CKP sensor or crankshaft pulley are faulty, replace faulty part. If voltage reading is as specified repair open or short circuit in wiring harness and connector of CKP sensor. After repair, repeat step  1.

Factory Service Tools

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.

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