SFI SYSTEM, Diagnostic DTC:P042000

DTC Code DTC Name
P042000 Catalyst System Efficiency Below Threshold Bank 1

MONITOR DESCRIPTION

The ECM uses sensors mounted in front of and behind the Three-Way Catalytic Converter (TWC) to monitor its efficiency.

The first sensor, the air fuel ratio sensor, sends pre-catalyst information to the ECM. The second sensor, the heated oxygen sensor, sends post-catalyst information to the ECM.

In order to detect any deterioration in the three-way catalytic converter, the ECM calculates the oxygen storage capacity of the three-way catalytic converter. This calculation is based on the voltage output of the heated oxygen sensor while performing active air fuel ratio control.

The oxygen storage capacity value is an indication of the oxygen storage capacity of the three-way catalytic converter. When the vehicle is being driven with a warm engine, active air fuel ratio control is performed for approximately 30 seconds. When it is performed, the ECM deliberately sets the air fuel ratio to lean or rich levels. If the cycle of the waveform for the heated oxygen sensor is long, the oxygen storage capacity is great. There is a direct correlation between the heated oxygen sensor and the oxygen storage capacity of the three-way catalytic converter.

The ECM uses the oxygen storage capacity value to determine the state of the three-way catalytic converter. If any deterioration has occurred, the ECM will illuminate the MIL and store a DTC.

This system determines the deterioration of the entire catalyst system (including the front and rear catalysts), by using the oxygen storage capacity value of the front catalyst, that is more sensitive than the rear catalyst, as the representative value. Therefore, be sure to replace the front and rear catalysts together when catalyst replacement is necessary.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

MIL

Memory

Note

P042000

Catalyst System Efficiency Below Threshold Bank 1

The oxygen storage capacity value is less than the standard value under active air fuel ratio control (2 trip detection logic).

  • Gas leak from exhaust system

  • Air fuel ratio sensor (sensor 1)

  • Heated oxygen sensor (sensor 2)

  • Exhaust manifold converter sub-assembly (TWC: Front catalyst) and front exhaust pipe assembly (TWC: Rear catalyst)

Comes on

DTC stored

SAE Code:

P0420

CATALYST LOCATION

A349315C03

*A

for Hatchback

-

-

*1

Exhaust Manifold Converter Sub-assembly (TWC: Front Catalyst)

*2

Front Exhaust Pipe Assembly (TWC: Rear Catalyst)

*3

Tail Exhaust Pipe Assembly

*4

Air Fuel Ratio Sensor (Sensor 1)

*5

Heated Oxygen Sensor (Sensor 2)

-

-
A355769C01

*A

for Wagon

-

-

*1

Exhaust Manifold Converter Sub-assembly (TWC: Front Catalyst)

*2

Front Exhaust Pipe Assembly (TWC: Rear Catalyst)

*3

Tail Exhaust Pipe Assembly

*4

Air Fuel Ratio Sensor (Sensor 1)

*5

Heated Oxygen Sensor (Sensor 2)

-

-
Note:

Replace the exhaust manifold converter sub-assembly (*1) and the front exhaust pipe assembly (*2) together when catalyst replacement is necessary. (Excluding air fuel ratio sensor*4 and heated oxygen sensor*5)

MONITOR STRATEGY

Required Sensors/Components (Main)

Air fuel ratio sensor

Heated oxygen sensor

Required Sensors/Components (Related)

Intake air temperature sensor (mass air flow meter sub-assembly)

Mass air flow meter sub-assembly

Crankshaft position sensor

Engine coolant temperature sensor

Frequency of Operation

Once per driving cycle

TYPICAL ENABLING CONDITIONS

Battery voltage

11 V or higher

Intake air temperature

-10°C (14°F) or higher

Engine coolant temperature

75°C (167°F) or higher

Atmospheric pressure

76 kPa(abs) [11.02 psi(abs)] or higher

Idling

Off

Engine speed

Less than 4000 rpm

Air fuel ratio sensor status

Activated

Fuel system status

Closed loop

Engine load

10% or higher, and less than 100%

All of the following conditions are met

-

Mass air flow rate

6.0 to 25 gm/sec.

Front catalyst temperature (estimated)

530°C (986°F) to 800°C (1472°F)

Rear catalyst temperature (estimated)

420°C (788°F) to 700°C (1292°F)

CONFIRMATION DRIVING PATTERN

Tip:

Performing this confirmation driving pattern will activate the catalyst efficiency monitor. This is very useful for verifying the completion of a repair.

A283969E26

  1. Connect the GTS to the DLC3.

  2. Turn the ignition switch to ON.

  3. Turn the GTS on.

  4. Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).

  5. Turn the ignition switch off and wait for at least 30 seconds.

  6. Turn the ignition switch to ON and turn the GTS on.

  7. Start the engine and warm it up until the engine coolant temperature is 75°C (167°F) or higher [A].

  8. Drive the vehicle at approximately 60 km/h (37 mph) for 10 minutes or more [B].

    CAUTION:

    When performing the confirmation driving pattern, obey all speed limits and traffic laws.

    Tip:

    Drive the vehicle while keeping the engine load as constant as possible.

  9. Turn the ignition switch off and wait for at least 30 seconds [C].

  10. Turn the ignition switch to ON and turn the GTS on.

  11. Start the engine and warm it up until the engine coolant temperature is 75°C (167°F) or higher [D].

  12. Drive the vehicle at approximately 60 km/h (37 mph) for 10 minutes or more [E].

    CAUTION:

    When performing the confirmation driving pattern, obey all speed limits and traffic laws.

    Tip:

    Drive the vehicle while keeping the engine load as constant as possible.

  13. Enter the following menus: Powertrain / Engine / Trouble Codes [F].

  14. Read the pending DTCs.

    Tip:

    • If a pending DTC is output, the system is malfunctioning.

    • If a pending DTC is not output, perform the following procedure.

  15. Enter the following menus: Powertrain / Engine / Utility / All Readiness.

  16. Input the DTC: P042000.

  17. Check the DTC judgment result.

    GTS Display

    Description

    NORMAL

    • DTC judgment completed

    • System normal

    ABNORMAL

    • DTC judgment completed

    • System abnormal

    INCOMPLETE

    • DTC judgment not completed

    • Perform driving pattern after confirming DTC enabling conditions

    N/A

    • Unable to perform DTC judgment

    • Number of DTCs which do not fulfill DTC preconditions has reached ECU memory limit
    Tip:

    • If the judgment result shows NORMAL, the system is normal.

    • If the judgment result shows ABNORMAL, the system has a malfunction.

    • If the judgment result shows INCOMPLETE or N/A and no pending DTC is output, perform the following procedure.

  18. Drive the vehicle at a speed between 75 and 100 km/h (47 and 62 mph) for 10 minutes or more [G].

    CAUTION:

    When performing the confirmation driving pattern, obey all speed limits and traffic laws.

    Tip:

    Drive the vehicle while keeping the engine load as constant as possible.

  19. Enter the following menus: Powertrain / Engine / Trouble Codes [H].

  20. Read the pending DTCs.

    Tip:

    • If a pending DTC is output, the system is malfunctioning.

    • If a pending DTC is not output, perform the following procedure.

  21. Enter the following menus: Powertrain / Engine / Utility / All Readiness.

  22. Input the DTC: P042000.

  23. Check the DTC judgment result.

    GTS Display

    Description

    NORMAL

    • DTC judgment completed

    • System normal

    ABNORMAL

    • DTC judgment completed

    • System abnormal

    INCOMPLETE

    • DTC judgment not completed

    • Perform driving pattern after confirming DTC enabling conditions

    N/A

    • Unable to perform DTC judgment

    • Number of DTCs which do not fulfill DTC preconditions has reached ECU memory limit
    Tip:

    • If the judgment result shows NORMAL, the system is normal.

    • If the judgment result shows ABNORMAL, the system has a malfunction.

CONDITIONING FOR SENSOR TESTING

Tip:

Perform the operation with the engine speeds and time durations described below prior to checking the waveforms of the air fuel ratio and heated oxygen sensors. This is to activate the sensors sufficiently to obtain appropriate inspection results.

A270243E20

  • (a) Connect the GTS to the DLC3.

  • (b) Start the engine and warm it up with all the accessories switched off until the engine coolant temperature stabilizes.

  • (c) Enter the following menus: Powertrain / Engine / Data List / A/F (O2) Sensor Voltage B1S1 and O2 Sensor Voltage B1S2.

  • (d) Run the engine at an engine speed of between 2500 rpm and 3000 rpm for at least 3 minutes.

  • (e) While running the engine at 3000 rpm for 2 seconds, and then 2000 rpm for 2 seconds, check the waveforms of the air fuel ratio and heated oxygen sensors using the GTS.

Tip:

  • If the voltage output of either the air fuel ratio or heated oxygen sensor does not fluctuate, or there is a noise in the waveform of either sensor, the sensor may be malfunctioning.

  • If the voltage outputs of both the sensors remain lean or rich, the air fuel ratio may be extremely lean or rich. In such cases, perform the Control the Injection Volume for A/F Sensor Active Test using the GTS.

  • If the Three-way Catalytic Converter (TWC) has deteriorated, the heated oxygen sensor (located behind the Three-way Catalytic Converter [TWC]) voltage output fluctuates up and down frequently, even under normal driving conditions (active air fuel ratio control is not performed).

A201081E21

CAUTION / NOTICE / HINT

Tip:

  • If a malfunction cannot be found when troubleshooting DTC P042000, a lean or rich abnormality may be the cause. Perform troubleshooting by following the inspection procedure for P017100 (System Too Lean) and P017200 (System Too Rich).

  • Sensor 1 refers to the sensor closest to the engine assembly.

  • Sensor 2 refers to the sensor farthest away from the engine assembly.

  • Read freeze frame data using the GTS. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air fuel ratio was lean or rich, and other data from the time the malfunction occurred.

PROCEDURE

  1. CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P042000)

    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the GTS on.

    4. Enter the following menus: Powertrain / Engine / Trouble Codes.

    5. Read the DTCs.

      Powertrain > Engine > Trouble Codes

      Result

      Result

      Proceed to

      DTC P042000 is output

      A

      DTC P042000 and other DTCs are output

      B
      Tip:

      If any DTCs other than P042000 are output, troubleshoot those DTCs first.

    B

    GO TO DTC CHART

    Click hereClick here

    A

  2. PERFORM ACTIVE TEST USING GTS (CONTROL THE INJECTION VOLUME FOR A/F SENSOR)

    1. Connect the GTS to the DLC3.

    2. Start the engine.

    3. Turn the GTS on.

    4. Warm up the engine and run the engine at an engine speed of 2500 rpm for approximately 90 seconds.

    5. Enter the following menus: Powertrain / Engine / Active Test / Control the Injection Volume for A/F Sensor / Data List / All Data / A/F (O2) Sensor Voltage B1S1 and O2 Sensor Voltage B1S2.

      Powertrain > Engine > Active Test

      Active Test Display

      Control the Injection Volume for A/F Sensor

      Data List Display

      A/F (O2) Sensor Voltage B1S1

      O2 Sensor Voltage B1S2

    6. Perform the Active Test with the engine idling (change the fuel injection volume).

    7. Monitor the voltage outputs of the air fuel ratio sensor and heated oxygen sensor (A/F (O2) Sensor Voltage B1S1 and O2 Sensor Voltage B1S2) displayed on the GTS.

      Tip:

      • The Control the Injection Volume for A/F Sensor operation lowers the fuel injection volume by 12.5% or increases the injection volume by 12.5%.

      • Each sensor reacts in accordance with increases and decreases in the fuel injection volume.

      • The air fuel ratio sensor has an output delay of a few seconds and the heated oxygen sensor has a maximum output delay of approximately 20 seconds.

      • If the sensor output voltage does not change (almost no reaction) while performing the Active Test, the sensor may be malfunctioning.

      Standard

      GTS Display

      (Sensor)

      Injection Volume

      Status

      Voltage

      A/F (O2) Sensor Voltage B1S1

      (Air fuel ratio)

      12.5%

      Rich

      Below 3.1 V

      -12.5%

      Lean

      Higher than 3.4 V

      O2 Sensor Voltage B1S2

      (Heated oxygen)

      12.5%

      Rich

      Higher than 0.55 V

      -12.5%

      Lean

      Below 0.4 V

      Result

      Status of A/F (O2) Sensor Voltage B1S1

      Status of O2 Sensor Voltage B1S2

      Actual air fuel ratio, air fuel ratio sensor and heated oxygen sensor condition

      Main Suspected Trouble Area

      Proceed to

      Lean/Rich

      Lean/Rich

      Normal

      • Three-way catalytic converter

      • Gas leak from exhaust system

      A

      Lean

      Lean/Rich

      Air fuel ratio sensor malfunction

      • Air fuel ratio sensor

      B

      Rich

      Lean/Rich

      Air fuel ratio sensor malfunction

      • Air fuel ratio sensor

      Lean/Rich

      Lean

      Heated oxygen sensor malfunction

      • Heated oxygen sensor

      • Gas leak from exhaust system

      C

      Lean/Rich

      Rich

      Heated oxygen sensor malfunction

      • Heated oxygen sensor

      • Gas leak from exhaust system

      Lean

      Lean

      Actual air fuel ratio lean

      • Extremely lean actual air fuel ratio

      • Gas leak from exhaust system

      D

      Rich

      Rich

      Actual air fuel ratio rich

      • Extremely rich actual air fuel ratio

      • Gas leak from exhaust system

      • Lean: During Control the Injection Volume for A/F Sensor, the air fuel ratio sensor output voltage (A/F (O2) Sensor Voltage B1S1) is consistently higher than 3.4 V, and the heated oxygen sensor output voltage (O2 Sensor Voltage B1S2) is consistently below 0.4 V.

      • Rich: During Control the Injection Volume for A/F Sensor, the A/F (O2) Sensor Voltage B1S1 is consistently below 3.1 V, and the O2 Sensor Voltage B1S2 is consistently higher than 0.55 V.

      • Lean/Rich: During Control the Injection Volume for A/F Sensor, the output voltage of the air fuel ratio sensor or heated oxygen sensor alternates correctly.

    B

    REPLACE AIR FUEL RATIO SENSORClick here

    C

    CHECK FOR EXHAUST GAS LEAKClick here

    D

    CHECK FOR EXHAUST GAS LEAKClick here

    A

  3. CHECK FOR EXHAUST GAS LEAK

    1. Check for exhaust gas leaks.

      OK

      No gas leaks.

    Result

    Proceed to

    OK

    NG
    OK

    REPLACE EXHAUST MANIFOLD CONVERTER SUB-ASSEMBLY (TWC: FRONT CATALYST) AND FRONT EXHAUST PIPE ASSEMBLY (TWC: REAR CATALYST)Click here

    NG

    REPAIR OR REPLACE EXHAUST GAS LEAK POINTClick here

  4. REPLACE AIR FUEL RATIO SENSOR

    1. Replace the air fuel ratio sensor.

      Click here

      Tip:

      Perform "Inspection After Repair" after replacing the air fuel ratio sensor.

      Click here

    Result

    Proceed to

    NEXT
    NEXT

    CHECK WHETHER DTC OUTPUT RECURS (DTC P042000)Click here

  5. CHECK FOR EXHAUST GAS LEAK

    1. Check for exhaust gas leaks.

      OK

      No gas leaks.

    Result

    Proceed to

    OK

    NG
    NG

    REPAIR OR REPLACE EXHAUST GAS LEAK POINTClick here

    OK

  6. REPLACE HEATED OXYGEN SENSOR

    1. Replace the heated oxygen sensor.

      Click here

    Result

    Proceed to

    NEXT
    NEXT

    CHECK WHETHER DTC OUTPUT RECURS (DTC P042000)Click here

  7. CHECK FOR EXHAUST GAS LEAK

    1. Check for exhaust gas leaks.

      OK

      No gas leaks.

    Result

    Proceed to

    OK

    NG
    NG

    REPAIR OR REPLACE EXHAUST GAS LEAK POINTClick here

    OK

  8. CHECK CAUSE OF EXTREMELY RICH OR LEAN ACTUAL AIR FUEL RATIO

    1. Check the cause of extremely rich or lean actual air fuel ratio, referring to the DTC P017100 Inspection Procedure.

      Click here

    Result

    Proceed to

    NEXT
    NEXT

    CHECK WHETHER DTC OUTPUT RECURS (DTC P042000)Click here

  9. REPAIR OR REPLACE EXHAUST GAS LEAK POINT

    1. Repair or replace the exhaust gas leak point.

      Tip:

      Perform "Inspection After Repair" after repairing or replacing the exhaust system.

      Click here

    Result

    Proceed to

    NEXT
    NEXT

  10. CHECK WHETHER DTC OUTPUT RECURS (DTC P042000)

    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the GTS on.

    4. Clear the DTCs.

      Powertrain > Engine > Clear DTCs

    5. Turn the ignition switch off and wait for at least 30 seconds.

    6. Turn the ignition switch to ON.

    7. Turn the GTS on.

    8. Start the engine.

    9. Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.

    10. Enter the following menus: Powertrain / Engine / Trouble Codes.

    11. Read the DTCs.

      Powertrain > Engine > Trouble Codes

      Result

      Result

      Proceed to

      DTC P042000 is output

      A

      DTCs are not output

      (No pending DTCs output)

      B
    B

    END

    A

  11. REPLACE EXHAUST MANIFOLD CONVERTER SUB-ASSEMBLY (TWC: FRONT CATALYST) AND FRONT EXHAUST PIPE ASSEMBLY (TWC: REAR CATALYST)

    Note:

    Replace the exhaust manifold converter sub-assembly (TWC: Front catalyst) and the front exhaust pipe assembly (TWC: Rear catalyst) together when catalyst replacement is necessary.

    Tip:

    Confirm the replacement parts, referring to the illustration in Catalyst Location.

    1. Replace the exhaust manifold converter sub-assembly (TWC: Front catalyst).

      Click here

    2. Replace the front exhaust pipe assembly (TWC: Rear catalyst).

      Click here

    Result

    Proceed to

    NEXT
    NEXT

    END