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2014 - Mazda6 - Engine

DTC P0421:00 [SKYACTIV-G 2.5]

NOTE:

Details On DTCs



DESCRIPTION

Catalytic converter system

DETECTION CONDITION

Determination conditions

  • The amount*1 of fuel supplied to the catalyst, from the period of recovery by fuel cut control until the HO2S indicates rich output (0.2 V), decreases below the specified value.

  • *1: The estimated value is calculated based on the A/F sensor signal.

Preconditions

  • Catalytic converter is activated sufficiently.

  • HO2S is activated sufficiently.

  • The following DTCs are not detected:

    • Misfire: P0300:00, P0301:00, P0302:00, P0303:00, P0304:00

    • Fuel injection correction: P0171:00, P0172:00, P2096:00, P2097:00

    • A/F sensor: P0130:00, P0131:00, P0132:00, P0133:00, P0134:00, P064D:00, P2237:00, P2243:00, P2251:00

    • HO2S: P0137:00, P0138:00, P013A:00, P0140:00

    • A/F sensor heater: P0031:00, P0032:00

    • HO2S heater: P0037:00, P0038:00

Drive cycle

  • 2

Self test type

  • CMDTC self test

Sensor used

  • A/F sensor, HO2S

FAIL-SAFE FUNCTION

  • Not applicable

VEHICLE STATUS WHEN DTCs ARE OUTPUT

  • Illuminates check engine light.

POSSIBLE CAUSE

  • HO2S malfunction

    • HO2S loose

  • A/F sensor malfunction

    • A/F sensor loose

    • Exhaust system leakage

    • A/F sensor deterioration

  • TWC deterioration or malfunction

  • PCM malfunction


System Wiring Diagram

Function Explanation (DTC Detection Outline)

Repeatability Verification Procedure

PID Item/Simulation Item Used In Diagnosis

PID/DATA monitor item table

Item

Definition

Unit

Condition/Specification

O2S11

A/F sensor input signal

µA

  • Idle (after warm up): Approx. -39 µA

  • Deceleration fuel cut (accelerator pedal released from engine speed of 4,000 rpm or more): Approx. 3.84 mA

O2S12

HO2S input signal

V

  • Idle (after warm up): 0—1.0 V

  • Deceleration fuel cut (accelerator pedal released from engine speed of 4,000 rpm or more): Approx. 0 V


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 (MODE 2)
  • Is the DTC P0421:00 on FREEZE FRAME DATA (Mode 2)?

Yes

Go to the next step.

No

Go to the troubleshooting procedure for DTC on FREEZE FRAME DATA (Mode 2).

(See DTC TABLE [SKYACTIV-G 2.5].)

3

PURPOSE: RECORD VEHICLE STATUS AT TIME OF DTC DETECTION TO UTILIZE WITH REPEATABILITY VERIFICATION
  • Has the FREEZE FRAME DATA (Mode 2)/snapshot data been recorded?

Yes

Go to the next step.

No

Record the FREEZE FRAME DATA (Mode 2)/snapshot data on the repair order, then go to the next step.

NOTE:

  • Recording can be facilitated using the screen capture function of the PC.

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 [SKYACTIV-G 2.5].)

  • Are any other PENDING CODEs and/or DTCs present?

Yes

Go to the applicable PENDING CODE or DTC inspection.

(See DTC TABLE [SKYACTIV-G 2.5].)

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 [SKYACTIV-G 2.5].)

    • 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

INSPECT RELATED SENSOR WIRING HARNESS AND CONNECTOR
  • Access the following PIDs using the M-MDS:

    (See ON-BOARD DIAGNOSTIC TEST [SKYACTIV-G 2.5].)

    • 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.


Troubleshooting Diagnostic Procedure



STEP

INSPECTION

RESULTS

ACTION

1

PURPOSE: INSPECT INSTALLATION OF HO2S
  • Inspect installation of HO2S.

  • Is the HO2S installed securely?

Yes

Go to the next step.

No

Retighten the HO2S, then go to Step 8.

(See HEATED OXYGEN SENSOR (HO2S) REMOVAL/INSTALLATION [SKYACTIV-G 2.5].)

2

PURPOSE: INSPECT INSTALLATION OF A/F SENSOR
  • Inspect installation of A/F sensor.

  • Is the A/F sensor installed securely?

Yes

Replace the A/F sensor and/or HO2S, then go to Step 8.

(See HEATED OXYGEN SENSOR (HO2S) REMOVAL/INSTALLATION [SKYACTIV-G 2.5].)

(See AIR FUEL RATIO (A/F) SENSOR REMOVAL/INSTALLATION [SKYACTIV-G 2.5].)

No

Retighten the A/F sensor, then go to Step 8.

(See AIR FUEL RATIO (A/F) SENSOR REMOVAL/INSTALLATION [SKYACTIV-G 2.5].)

3

PURPOSE: INSPECT INSTALLATION OF HO2S
  • Inspect installation of HO2S.

  • Is the HO2S installed securely?

Yes

Go to the next step.

No

Retighten the HO2S, then go to Step 8.

(See HEATED OXYGEN SENSOR (HO2S) REMOVAL/INSTALLATION [SKYACTIV-G 2.5].)

4

PURPOSE: INSPECT INSTALLATION OF A/F SENSOR
  • Inspect installation of A/F sensor.

  • Is the A/F sensor installed securely?

Yes

Go to the next step.

No

Retighten the A/F sensor, then go to Step 8.

(See AIR FUEL RATIO (A/F) SENSOR REMOVAL/INSTALLATION [SKYACTIV-G 2.5].)

5

PURPOSE: INSPECT EXHAUST SYSTEM FOR LEAKAGE
  • Visually inspect for exhaust gas leakage from the exhaust system.

  • Is there any malfunction?

Yes

Repair or replace the malfunctioning part according to the inspection results, then go to Step 8.

No

Go to the next step.

6

PURPOSE: VERIFY IF OTHER DTCs ARE DISPLAYED

Yes

Go to the applicable PENDING CODE or DTC inspection.

(See DTC TABLE [SKYACTIV-G 2.5].)

Go to the next step.

No

Go to the next step.

7

PURPOSE: VERIFY CATALYTIC CONVERTER MALFUNCTION

Yes

Replace the TWC, then go to the next step.

(See EXHAUST SYSTEM REMOVAL/INSTALLATION [SKYACTIV-G 2.5].)

No

DTC troubleshooting completed.

8

PURPOSE: VERIFICATION OF VEHICLE REPAIR COMPLETION

Yes

Repeat the inspection from Step 1.

Go to the next step.

No

Go to the next step.

9

PURPOSE: VERIFY IF THERE IS ANY OTHER MALFUNCTION
  • Is any other DTC or pending code stored?

Yes

Go to the applicable DTC inspection.

(See DTC TABLE [SKYACTIV-G 2.5].)

No

DTC troubleshooting completed.




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