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Home >> Mazda >> 2019 >> CX-9 Signature >> Repair and Diagnosis >> Engine Performance >> System >> On-Board Diagnostic - Engine Control System (2 Of 3) >> DTC P0421-00: Catalytic Converter System >> Function Inspection Using M-MDS
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Function Inspection Using M-MDS

DIANOSTIC PROCEDURE - FUNCTION INSPECTION USING M-MDS

STEP INSPECTION RESULTS ACTION
1 PURPOSE: 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.
2 PURPOSE: IDENTIFY TRIGGER DTC FOR FREEZE FRAME DATA 
  • Is the DTC P0421:00 on FREEZE FRAME DATA?
 Yes Go to the next step.
No Go to the troubleshooting procedure for DTC on FREEZE FRAME DATA.
(See DTC TABLE .)
3 PURPOSE: RECORD FREEZE FRAME DATA/SNAPSHOT DATA AND DIAGNOSTIC MONITORING TEST RESULTS TO UTILIZE WITH REPEATABILITY VERIFICATION 
NOTE:
  • Recording can be facilitated using the screen capture function of the PC.
  • Record the FREEZE FRAME DATA/snapshot data and DIAGNOSTIC MONITORING TEST RESULTS (catalyst related) on the repair order.
 - Go to the next step.
4 PURPOSE: VERIFY RELATED PENDING CODE AND/OR DTC 
  • Switch the ignition off, then ON (engine off).
  • Perform the Pending Trouble Code Access Procedure and DTC Reading Procedure. (See ON-BOARD DIAGNOSTIC TEST .)
  • Are any other PENDING CODEs and/or DTCs present?
 Yes Go to the applicable PENDING CODE or DTC inspection.
(See DTC TABLE .)
Go to the next step.
No Go to the next step.
5 PURPOSE: VERIFY A/F SENSOR AND HO2S INPUT SIGNAL 
  • Start the engine and warm it up completely.
  • Access the following PIDs using the M-MDS: (See ON-BOARD DIAGNOSTIC TEST .)
    • O2S11
    • O2S12
  • Drive the vehicle under the following conditions.
    WARNING:
    • 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.
    • While performing this step, always operate the vehicle in a safe and lawful manner.
    • After increasing the engine speed to 3, 000 RPM, decelerate using engine braking.
  • Is the displayed PID value as follows?
    • O2S11: 0.25 mA or more
    • O2S12: 0.3 V or less
 Yes Go to the troubleshooting procedure to perform the procedure from Step 3.
No Go to the next step.
6 PURPOSE: INSPECT RELATED SENSOR WIRING HARNESS AND CONNECTOR 
  • Access the following PIDs using the M-MDS: (See ON-BOARD DIAGNOSTIC TEST .)
    • O2S11
    • O2S12
  • When the PCM, A/F sensor and HO2S are shaken, does the PID value include a PID item which has changed?
 Yes Inspect the related wiring harness and connector.
  • Repair or replace the malfunctioning part.

Go to the troubleshooting procedure to perform the procedure from Step 8.
No Go to the troubleshooting procedure to perform the procedure from Step 1.
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