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Home >> Mazda >> 2011 >> 6 s Touring Plus >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 1 (On-Board Diagnostic [Engine Control System MZR 2.5]) >> DTC P0301:00, P0302:00, P0303:00, P0304:00 >> Diagnostic procedure

Diagnostic procedure

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DIAGNOSTIC PROCEDURE CHART

STEP INSPECTION ACTION
1 VERIFY FREEZE FRAME DATA (MODE 2)/SNAPSHOT DATA AND DIAGNOSTIC MONITORING TEST RESULTS HAVE BEEN RECORDED
  • Have the FREEZE FRAME DATA (Mode 2)/snapshot data and DIAGNOSTIC MONITORING TEST RESULTS (misfire related) been recorded?
Yes Go to the next step.
No Record the FREEZE FRAME DATA (Mode 2)/snapshot date and DIAGNOSTIC MONITORING TEST RESULTS on tie repair order, then go to the next step.
2 VERIFY RELATED REPAIR INFORMATION AVAILABILITY 
  • Verify related Service Bulletins and/or on-line repair information availability.
  • Is any related repair information available?
Yes Perform repair or diagnosis according to the available repair information.
  • If the vehicle is not repaired, go to the next step.
No Go to the next step.
3 VERIFY RELATED PENDING AND STORED DTC 
  • Switch the ignition to off, then to ON (engine off).
  • Verify pending and stored DTCs using the M-MDS.

    (See ON-BOARD DIAGNOSTIC TEST .)

  • Are any other DTCs present?
Yes Go to the applicable DTC inspection.
(See DTC TABLE .)
No Go to the next step.
4 VERIFY CURRENT INPUT SIGNAL STATUS 
  • Access the following PIDs using the M-MDS.

    (See ON-BOARD DIAGNOSTIC TEST .)

    • APP1
    • APP2
    • ECT
    • IAT
    • MAF
    • RPM
    • TPREL
    • VSS
  • Is there any signal that is far out of specification when switch the ignition to ON and the engine idles?

(See PCM INSPECTION .)
Yes Inspect the suspected sensor and related wiring harness. Repair or replace the malfunctioning part according to the inspection results, then go to Step 16.
No Go to the next step.
5 VERIFY CURRENT INPUT SIGNAL STATUS UNDER FREEZE FRAME DATA (MODE 2) CONDITION 
CAUTION:
  • While performing this step, always operate the vehicle in a safe and lawful manner.
  • When the M-MDS is used to observe monitor system status while driving, be sure to have another technician with you, or record the data in the M-MDS using the PID/DATA MONITOR AND RECORD capturing function and inspect later.
  • Access the following PIDs under the FREEZE FRAME DATA (Mode 2) condition. (See ON-BOARD DIAGNOSTIC TEST .)
    • APP1
    • APP2
    • ECT
    • IAT
    • MAF
    • RPM
    • TP REL
    • VSS
  • Is there any signal which causes drastic changes?
Yes Inspect the suspected sensor and related wiring harness. Repair or replace the malfunctioning part according to the inspection results, then go to Step 16.
No Go to the next step.
6 INSPECT IGNITION SYSTEM OPERATION  Yes Go to Step 10.
No Go to the next step.
7 INSPECT SPARK PLUG CONDITION  Yes Replace the spark plug, then go to Step 16.
(See SPARK PLUG REMOVAL/INSTALLATION .)
No Go to the next step.
8 INSPECT IGNITION COIL RELATED WIRING HARNESS OR CONNECTOR CONDITION 
  • Inspect the ignition coil related wiring harness condition (intermittent open or short) for all cylinders and connector for poor connection (such as damaged/pulled-out pins, corrosion).
  • Is there any malfunction?
Yes Repair or replace the malfunctioning part according to inspection results, then go to Step 16.
No Go to the next step.
9 INSPECT IGNITION COIL  Yes Replace the malfunctioning ignition coil, then go to Step 16. (See IGNITION COIL REMOVAL/INSTALLATION .)
No Go to the next step.
10 INSPECT INTAKE AIR SYSTEM FOR AIR SUCTION 
  • Inspect for air leakage at the following:
    • Around connection of dynamic chamber and intake manifold
    • Around connection of intake manifold and cylinder head
    NOTE:
    • Engine speed may change when rust penetrating agent is sprayed on the air suction area.
  • Is there any leakage?
Yes Repair or replace the malfunctioning part according to inspection results, then go to Step 16.
No Go to the next step.
11 INSPECT FUEL INJECTOR OPERATION 
  • Remove the intake air system parts. (See INTAKE-AIR SYSTEM REMOVAL/INSTALLATION .)
  • Disconnect the fuel injector connector on suspected cylinder.
  • Connect the test light to the fuel injector terminals.
  • Inspect the test light during cranking.
  • Does the test light illuminate?
Yes Go to the next step.
No Go to Step 14.
12 INSPECT FUEL INJECTOR RELATED WIRING HARNESS OR CONNECTOR CONDITION 
  • Inspect the fuel injector related wiring harness condition (intermittent open or short) and connector for poor connection (such as damaged/pulled-out pins, corrosion).
  • Is there any malfunction?
Yes Repair or replace the malfunctioning part according to inspection results, then go to Step 16.
No Go to the next step.
13 INSPECT FUEL INJECTOR 
  • Remove the fuel injector.

    (See FUEL INJECTOR REMOVAL/INSTALLATION .)

  • Switch the fuel injector with the fuel injector on other cylinder.
  • Start the engine and idle it.
  • Is the misfire DTC for cylinder which has a suspected fuel injector?
Yes Replace the malfunctioning fuel injector, then go to Step 16. (See FUEL INJECTOR REMOVAL/INSTALLATION .)
No Go to the next step.
14 INSPECT ENGINE COMPRESSION  Yes Perform the engine overhaul for repairs, then go to Step 16.
No Go to the next step.
15 INSPECT SEALING OF ENGINE COOLANT PASSAGE  Yes Repair or replace the malfunctioning part according to the inspection results, then go to the next step.
No Go to the next step.
16 VERIFY DTC TROUBLESHOOTING COMPLETED 
  • Make sure to reconnect all disconnected connectors.
  • Clear the DTC from the PCM memory using the M-MDS.

    (See AFTER REPAIR PROCEDURE .)

  • Start the engine and warm it up completely.
  • Perform the KOER self test.

    (See KOEO/KOER SELF TEST .)

  • Is the PENDING CODE for this DTC present?
Yes Repeat the inspection from Step 1.
  • If the malfunction recurs, replace the PCM.

(See PCM REMOVAL/INSTALLATION .) Go to the next step.
No Go to the next step.
17 VERIFY AFTER REPAIR PROCEDURE  Yes Go to the applicable DTC inspection.
(See DTC TABLE .)
No DTC troubleshooting completed.