Diagnostic Procedures

WARNING: This page is about a different car, the 2003 Mazda B4000, 2003 Mazda B3000, and 2003 Mazda B2300. However, it is still accessible from the selected car via links, so may be relevant.

If QUICK TEST was not performed, go to QUICK TEST under SELF-DIAGNOSTIC SYSTEM. If QUICK TEST was performed, go to next step.

NOTE: Electronic ignition engine timing is PCM controlled. Electronic ignition timing is NOT adjustable. DO NOT attempt to check base timing. Base timing ignition readings will be inaccurate.

Determine Which Coil Is Not Firing - Determine which coil is not firing using information from IGNITION COIL-TO-CYLINDER CORRELATION (COIL PACK) table. Record cylinder number, coil driver and breakout box terminal from table. If cylinder number, coil driver and PCM pin numbers have been recorded, go to next step. If information has not been recorded, obtain required information. Go to next step.

IGNITION COIL-TO-CYLINDER CORRELATION (COIL PACK)

Application & Cylinder No.	Coil Driver	Breakout Box Terminal No.	DTC
2.3L
1	1	26	P0351
3	2	52	P0352
4	1	26	P0351
2	2	52	P0352
3.0L & 4.0L
1	1	26	P0351
4	2	52	P0352
2	3	78	P0353
5	1	26	P0351
3	2	52	P0352
6	3	78	P0353

Check IGN START/RUN Voltage To Coil Pack - Disconnect coil harness connector. With KOEO, measure voltage of IGN START/ON (RUN) circuit between ignition coil harness connector and ground. See Fig 1 -Fig 3 . Record reading. Turn ignition off. If voltage reading is more than 10 volts, go to next step. If voltage reading is not as specified, a fault is present in IGN START/ON (RUN) circuit. Check No. 19 fuse (25-amp) in instrument panel fuse panel. If fuse is okay, repair open circuit in Red/Light Green wire between No. 19 fuse (25-amp) in instrument panel fuse panel and ignition coil pack harness connector. See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. If fuse is open, check IGN START/ON (RUN) circuit for short to ground. Repair as necessary. After repair, go to step 12 .

Fig 1: Identifying Coil 3-Pin Harness Connector (2.3L)
Courtesy of MAZDA MOTORS CORP.

Fig 2: Identifying Coil 4-Pin Harness Connector (3.0L)
Courtesy of MAZDA MOTORS CORP.

Fig 3: Identifying Coil 4-Pin Harness Connector (4.0L)
Courtesy of MAZDA MOTORS CORP.
Check Functionality Of Suspect Coil Driver (CD) Circuit - Connect test light between IGN START/ON (RUN) circuit and suspect CD circuit (determined from IGNITION COIL-TO-CYLINDER CORRELATION (COIL PACK) table) at ignition coil harness connector. Disconnect Inertia Fuel Shutoff (IFS) switch to disable fuel pump. Observe test light while cranking engine. If test light blinked consistently, go to step 10 . If test light did not blink consistently, go to next step.
Check Suspect CD Circuit For Open In Harness - Turn ignition off. Disconnect PCM 104-pin harness connector. Connect Breakout Box (49-UN01-130) to PCM harness connector only. See Figure . Measure resistance of suspect CD circuit between breakout box terminal and ignition coil harness connector (determined from IGNITION COIL-TO-CYLINDER CORRELATION (COIL PACK) table). If resistance reading is less than 5 ohms, go to next step. If resistance reading is 5 ohms or more, repair open circuit. See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to step 12 .
Check Suspect CD Circuit For Short To VPWR In Harness - With KOEO, measure voltage of suspect CD circuit between breakout box terminal (determined from IGNITION COIL-TO-CYLINDER CORRELATION (COIL PACK) table) and ground. Turn ignition off. If voltage reading is less than one volt, go to next step. If voltage reading is one volt or more, repair short circuit. After repair, go to step 12 .
Check Suspect CD Circuit For Short To Ground In Harness - Disconnect scan tool. Measure resistance of suspect CD circuit between breakout box terminal (determined from IGNITION COIL-TO-CYLINDER CORRELATION (COIL PACK) table) and ground. If resistance reading is more than 10,000 ohms, go to next step. If resistance reading is less than 10,000 ohms, repair short circuit. After repair, go to step 9 to check for damaged coil.
Perform Intermittent Test On Suspect CD Circuit Harness - Connect DVOM to suspect CD circuit between breakout box terminal (determined from IGNITION COIL-TO-CYLINDER CORRELATION (COIL PACK) table) and ignition coil harness connector. While observing DVOM, wiggle and bend CD harness from PCM 104-pin harness connector to ignition coil harness connector. If resistance reading fluctuates, repair intermittent fault in wire harness. See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to step 12 . If resistance reading does not fluctuate, replace faulty PCM. After repair, go to next step to check for damaged coil.
Check Suspect Primary Coil For Open - Measure resistance of suspect coil between CD and IGN START/ON (RUN) circuits at ignition coil connector. If resistance reading is less than 5 ohms, go to step 12 . If resistance reading is 5 ohms or more, replace faulty ignition coil. After repair, go to step 12 .
Check Suspect Secondary Coil For Open - Measure resistance between CD and IGN START/ON (RUN) circuits at ignition coil connector. If resistance reading is less than 5 ohms, go to step 12 . If resistance reading is 5 ohms or more, replace faulty ignition coil. After repair, go to step 12 .

NOTE: Ignition coil resistance for 2.3L engine is not available from manufacturer.

Check Suspect Secondary Coil For Open - Remove both plug wires from ignition coil of suspect cylinder. Measure resistance of suspected coil driver between terminals. Resistance specifications are 8600-11,100 ohms (3.0L) or 11,500-15,500 ohms (4.0L). If resistance reading is within specification and DTC P0350 is set, go to DTC P0350: IGNITION COIL CIRCUIT MALFUNCTION . If resistance reading is within specification and no additional ignition DTCs are set, go to INTERMITTENT testing under SYSTEM TESTS. If resistance reading is not within specification, replace faulty ignition coil. After repair, go to next step.
Drive Cycle - Reconnect all electrical connectors. Clear DTCs from PCM memory using scan tool. 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. After repair, go to next step.
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.