Engine Controls - Misfire Detection Procedure

TSB: 01-029/07

2003 2004 MAZDA6 3.0L - ENGINE MISFIRE DETECTION PROCEDURE

APPLICABLE MODEL(S)/VINS
2003 - 2004 Mazda6 3.0L

DESCRIPTION

On some vehicles, the engine may have an intermittent rough idle, hesitation, and/or misfire.The concern may occur with the Malfunction Indicator Light (MIL) illuminated and a Diagnostic Trouble Code (DTC) P0300 set, or there may be no MIL illumination or DTC set.

Customers having this concern should have their vehicle repaired using the following repair procedure.

REPAIR PROCEDURE

NOTE:
^ The following repair procedure WILL NOT work on 2005-06 Mazda6 vehicles.

^ Before attempting any repairs, be sure concern can be duplicated at time of diagnosis. Using M-MDS and software version B46 or later, perform the following procedure.

1. Verify customer concern.

2. Install M-MDS to DLC2 connector under dash (below hood release).

3. After M-MDS IDs vehicle, select "TOOLBOX" icon at top of screen.

4. Select POWERTRAIN, then MISFIRE CHECK, press tick mark.





5. Be sure PCM has learned vehicles crank profile before beginning diagnosis. Follow screen instructions below to learn vehicles crank profile.





6. This screen shows misfire counter, correct cylinder numbers and locations. When a misfire occurs, the misfire counter box next to each cylinder will display a number greater than zero (0).

^ If value shown is zero (0), no misfire was detected in the corresponding cylinder.

^ If any value other than zero (0) is shown, a misfire was detected in the corresponding cylinder.





7. Repair according to Workshop Manual (section 01-03).

8. Verify repair.





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