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Home >> Mazda >> 2021 >> 3 Base >> Repair and Diagnosis (Single Page) >> Engine Performance >> System >> On-Board Diagnostic - Engine Control System (VINS 7, L, M) (3 Of 4) >> DTC P2251-00: Open Circuit Between A/F Sensor Terminal D And Pcm Terminal 1S >> PID Item/Simulation Item Used In Diagnosis >> Function Inspection Using M-MDS

Function Inspection Using M-MDS

DIAGNOSTIC PROCEDURE - FUNCTION INSPECTION USING M-MDS

Step Inspection Results Action
1 PURPOSE: VERIFY RELATED REPAIR INFORMATION OR SERVICE INFORMATION AVAILABILITY
  • Verify related Service Bulletins, on-line repair information, or Service Information availability.
  • Is any related Information available?
 Yes Perform repair or diagnosis according to the available information.
  • If the vehicle is not repaired, go to the next step.
No Go to the next step.
2 PURPOSE: RECORD VEHICLE STATUS WHEN DTC WAS DETECTED TO UTILIZE WITH REPEATABILITY VERIFICATION
  • Record the freeze frame data/snapshot data and diagnostic monitoring test results (A/F sensor, HO2S related).
    NOTE:
    • Recording can be facilitated using the screen capture function of the PC.
 - Go to the next step.
3 PURPOSE: INSPECT A/F SENSOR CONNECTOR FOR MALFUNCTION
  • Inspect the applicable connector and terminal. (See CONNECTOR INSPECTION .)
  • Are the connector and terminal normal?
 Yes Go to the next step.
No Repair or replace the malfunctioning location.
Go to Troubleshooting Diagnostic Procedure to perform the repair completion verification.
4 PURPOSE: INSPECT PCM CONNECTOR FOR MALFUNCTION
  • Inspect the applicable connector and terminal. (See CONNECTOR INSPECTION .)
  • Are the connector and terminal normal?
 Yes Go to the next step.
No Repair or replace the malfunctioning location.
Go to Troubleshooting Diagnostic Procedure to perform the repair completion verification.
5 PURPOSE: INSPECT A/F SENSOR SIGNAL CIRCUIT FOR OPEN CIRCUIT
  • Inspect the applicable circuit for open circuit. (See CIRCUIT INSPECTION .)
  • Is the circuit normal?
 Yes Go to the next step.
No Repair or replace the malfunctioning location.
Go to Troubleshooting Diagnostic Procedure to perform the repair completion verification.
6 PURPOSE: DETERMINE INTEGRITY OF A/F SENSOR
  • Start the engine and warm it up completely.
  • Access the A/F_SEN_CUR PID using the MMDS. (See PID/DATA MONITOR INSPECTION .)
  • 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?
      • A/F_SEN_CUR: 0.25 mA or more
 Yes Go to Troubleshooting Diagnostic Procedure to perform the repair completion verification.
No Go to the next step.
7 PURPOSE: VERIFY CONNECTOR CONNECTIONS
  • Access the A/F_SEN_CUR PID using the MMDS. (See PID/DATA MONITOR INSPECTION .)
  • Does the PID value fluctuate when the following connectors are shaken?
    • A/F sensor
      • PCM
 Yes Repair or replace the applicable wiring harness or connector parts.
Go to Troubleshooting Diagnostic Procedure to perform the repair completion verification.
No Replace the A/F sensor.
(See AIR FUEL RATIO (A/F) SENSOR REMOVAL/INSTALLATION [(VIN M) (US)] .)
(See AIR FUEL RATIO (A/F) SENSOR REMOVAL/INSTALLATION [(VIN 7 & VIN L) (US)] .)
Go to Troubleshooting Diagnostic Procedure to perform the repair completion verification.
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