DTC P0421:00 [SKYACTIV-D 2.2]

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Note
•  To determine the malfunctioning part, proceed with the diagnostics from “Function Inspection Using M-MDS”.

Details On DTCs

DESCRIPTION

Catalyst efficiency below threshold
DETECTION CONDITION
Determination conditions
•  The difference between the exhaust gas temperature before and after passing the catalytic converter is specified value or less.
Preconditions
•  Battery voltage: 8 V or more
•  Engine speed: 1,200—2,000 rpm
•  Fuel injection amount: 10—25 mm3/ stroke
•  IAT (IAT sensor No.1): –10 °C {14 °F} or more
•  Barometric pressure: 65 kPa {0.67 kgf/cm2, 9.5 psi} or more
•  ECT: 60 °C {140 °F} or more
•  Vehicle speed: 20—140 km/h {13.0—86.9 mph}
•  Accumulated PM calculated from fuel injection amount: 0.8—4.0 g/l {0.05—0.25 lb/ft3}
•  Amount of soot calculated based on difference in pressure between exhaust gas pressure before and after diesel particulate filter: 0.06—2.0 g/l {0.037—0.124 lb/ft3}
•  Traveled distance after diesel particulate filter regeneration: 36—400 km {23—248 mile}
•  Exhaust gas temperature before passing catalytic converter: 140—195 °C {284—383 °F} (MTX)
•  Exhaust gas temperature before passing catalytic converter: 160—195 °C {320—383 °F} (ATX)
•  Exhaust gas temperature after passing catalytic converter (at engine start): 0—200 °C {32—392 °F}
•  Exhaust gas temperature after passing catalytic converter: 135—250 °C {275—482 °F}
Drive cycle
•  2
Self test type
•  CMDTC self test
Sensor used
•  Exhaust gas temperature sensor No.2
•  Exhaust gas temperature sensor No.3
FAIL-SAFE FUNCTION
•  Not applicable
VEHICLE STATUS WHEN DTCs ARE OUTPUT
•  Check engine light is illuminated
POSSIBLE CAUSE
•  Erratic signal to PCM
―  Exhaust gas temperature sensor No.2 signal malfunction
―  Exhaust gas temperature sensor No.3 signal malfunction
―  Input signal part connector or terminals malfunction
―  Input signal part related circuit malfunction
•  Exhaust gas leakage from exhaust system
•  Exhaust gas temperature sensor No.2 malfunction
•  Exhaust gas temperature sensor No.3 malfunction
•  Improper operation of fuel injector
•  Catalytic converter or diesel particulate filter malfunction (deformation, damage)
•  PCM malfunction


System Wiring Diagram

•  Not applicable

Function Explanation (DTC Detection Outline)

•  The PCM performs diagnosis by monitoring the reaction heat which occurs during the oxidation reaction of the catalytic converter.
•  The PCM monitors the exhaust gas temperature before and after the catalytic converter using exhaust gas temperature sensor No.2 and No.3.
•  The PCM performs post injection when the preconditions are met during a drive cycle and it effectuates the oxidation reaction of the catalytic converter. At this time, based on the No.2 and No.3 signals, the PCM detects the average and maximum values of each of the exhaust gas temperatures before and after the catalytic converter within the specified time. If the average and maximum exhaust gas temperature values after the catalytic converter are less than the average and maximum exhaust gas temperature values before the catalytic converter, the PCM determines that the performance of catalytic converter has lowered due to deterioration/damage.
•  If the PCM determines a malfunction, it stores a pending code.
•  If the PCM determines that the malfunction recurs from the next drive cycle and thereafter, it stores a DTC and turns on the check engine light.
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Repeatability Verification Procedure

1.  Clear the DTC from the PCM memory using the M-MDS. (See CLEARING DTC [SKYACTIV-D 2.2].)
2.  Visually inspect the exhaust gas temperature sensor No.2 and No.3 for damage and open circuit.
3.  Perform the DTC Reading Procedure. (See ON-BOARD DIAGNOSTIC TEST [SKYACTIV-D 2.2].)
4.  Perform compulsory DPF regeneration. (See COMPULSORY DIESEL PARTICULATE FILTER REGENERATION [SKYACTIV-D 2.2].)
5.  Access the following PIDs using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [SKYACTIV-D 2.2].)
―  EXHTEMP2
―  EXHTEMP3
6.  Drive the vehicle and put PID EXHTEMP2 and EXHTEMP3 each under the following conditions.
―  EXHTEMP2: 300 °C {572 °F} or more
―  EXHTEMP3: 500 °C {932 °F} or more

PID Item/Simulation Item Used In Diagnosis

PID/DATA monitor item table

Item

Definition

Unit

Condition/Specification
EXHTEMP2
Exhaust temperature sensor No.2
°C, °F
•  Displays the exhaust gas temperature before passing catalytic converter
EXHTEMP3
Exhaust temperature sensor No.3
°C, °F
•  Displays the exhaust gas temperature after passing catalytic converter

Function Inspection Using M-MDS

STEP

INSPECTION

ACTION
1
PURPOSE: VERIFY RELATED SERVICE INFORMATION AVAILABILITY
•  Verify related Service Information availability.
•  Is any related Service Information available?
Yes
Perform repair or diagnosis according to the available Service 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 [SKYACTIV-D 2.2].)
3
PURPOSE: RECORD VEHICLE STATUS AT TIME OF DTC DETECTION 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 on the repair order.
—
Go to the next step.
4
PURPOSE: VERIFY IF DIAGNOSTIC RESULT IS AFFECTED BY OTHER RELATED DTCs OCCURRING
•  Switch the ignition off, then ON (engine off).
•  Perform the Pending Trouble Code Access Procedure and DTC Reading Procedure.
•  Is the other PENDING CODE/DTC also present?
Yes
Go to the applicable DTC inspection.
(See DTC TABLE [SKYACTIV-D 2.2].)
No
Go to the next step.
5
PURPOSE: VERIFY IF THERE IS PID ITEM CAUSING DRASTIC CHANGES OF ACCELERATION FLUCTUATION BY INPUT SIGNAL TO PCM AND DSC HU/CM
•  Access the following PIDs using the M-MDS:
―  EXHTEMP2
―  EXHTEMP3
•  Is there any signal that is far out of specification?
Yes
Go to the next step.
No
Go to the troubleshooting procedure to perform the procedure from Step 1.
6
PURPOSE: VERIFY CONNECTOR CONNECTIONS
•  Access the following PIDs using the M-MDS:
Warning
•  A hot engine and exhaust system can cause severe burns. Turn off the engine and wait until they are cool before removing the exhaust system.
―  EXHTEMP2
―  EXHTEMP3
•  When the following parts are shaken, does the PID value include a PID item which has changed?
―  Exhaust gas temperature sensor No.2
―  Exhaust gas temperature sensor No.3
―  PCM
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 5.
No
Go to the troubleshooting procedure to perform the procedure from Step 1.


Troubleshooting Diagnostic Procedure

Intention of troubleshooting procedure
•  Step 1
―  Perform inspection of exhaust gas leakage from exhaust system.
•  Step 2—4
―  Perform inspection of each separate part.
•  Step 5—6
―  Verify that the primary malfunction is resolved and there are no other malfunctions.

Function Inspection Using M-MDS

STEP

INSPECTION

ACTION
1
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 5.
No
Go to the next step.
2
PURPOSE: INSPECT EXHAUST GAS TEMPERATURE SENSOR NO.2
•  Inspect the exhaust gas temperature sensor No.2.
•  Is there any malfunction?
Yes
Replace the exhaust gas temperature sensor No.2, then go to Step 5.
(See EXHAUST GAS TEMPERATURE SENSOR REMOVAL/INSTALLATION [SKYACTIV-D 2.2].)
No
Go to the next step.
3
PURPOSE: INSPECT EXHAUST GAS TEMPERATURE SENSOR NO.3
•  Inspect the exhaust gas temperature sensor No.3.
•  Is there any malfunction?
Yes
Replace the exhaust gas temperature sensor No.3, then go to Step 5.
(See EXHAUST GAS TEMPERATURE SENSOR REMOVAL/INSTALLATION [SKYACTIV-D 2.2].)
No
Go to the next step.
4
PURPOSE: INSPECT FOR MALFUNCTION FUEL INJECTOR
•  Inspect the fuel injector.
•   Is there any malfunction?
Yes
Replace the suspect fuel injector, then go to the next step.
(See FUEL INJECTOR REMOVAL/INSTALLATION [SKYACTIV-D 2.2].)
No
Catalytic converter or diesel particulate filter can be considered the cause.
•  Replace the catalytic converter, then go to the next step.
5
PURPOSE: PERFORM DTC INSPECTION AND VERIFY IF MALFUNCTIONING PART IS PCM
•  Always reconnect all disconnected connectors.
•  Clear the DTC from the PCM memory using the M-MDS.
•  Implement the repeatability verification procedure.
•  Perform the Pending Trouble Code Access Procedure.
•  Is the PENDING CODE for this DTC present?
Yes
Repeat the inspection from Step 1.
•  If the malfunction recurs, replace the PCM.
Go to the next step.
No
Go to the next step.
6
PURPOSE: VERIFY AFTER REPAIR PROCEDURE
•  Perform the “AFTER REPAIR PROCEDURE”.
•  Are any DTCs present?
Yes
Go to the applicable DTC inspection.
(See DTC TABLE [SKYACTIV-D 2.2].)
No
DTC troubleshooting completed.