DTC P0420, P0430 [MZI-3.7 (PCM CONNECTOR (2 TYPES))]

id0102e3880900

DTC P0420

DTC P0430

P0420: Catalyst system efficiency below threshold (RH)

P0430: Catalyst system efficiency below threshold (LH)
DETECTION CONDITION
•  P0420: When the vehicle is driven under the following conditions and if the right bank catalyst system efficiency is allowable value or lower, the PCM stores P0430.
•  P0430: When the vehicle is driven under the following conditions and if the left bank catalyst system efficiency is allowable value or lower, the PCM stores P0430.
MONITORING CONDITIONS
•  Engine speed: 1,000—2,500 rpm
•  Charging efficiency (ce): 0.2—0.65
•  Intake air amount: 16—45 g/s {2—6 lb/min}
•  Vehicle speed: 33—128 km/h {20—80 mph}
•  Intake air temperature: -6.6—82.2 °C {20—180 °F}
•  Engine coolant temperature: 65.6—110.0 °C {150—230 °F}
•  Air fuel ratio (λ): 0.9—1.1
•  Remaining fuel amount: 15—100%
POSSIBLE CAUSE
•  Cylinder misfiring
•  Damaged exhaust system pipe
•  Damaged exhaust manifold
•  Damaged muffler/tailpipe ass
•  HO2S looseness
•  Damaged TWC
•  Use of leaded fuel
•  Oil contamination
•  Damaged HO2S
•  Malfunctioning CHT sensor
•  Downstream HO2S wires improperly connected
•  Fuel pressure too high
•  PCM malfunction
Note
•  Internal deterioration of a catalytic converter is usually caused by abnormal engine operation front of the catalyst. Events that can produce higher than normal temperatures in the catalyst are particularly suspect, such as misfiring.Incorrect HO2S signal input (e.g., rich/lean signal when engine is operating under rich/lean conditions) can cause an abnormal temperature increase in the catalyst. CHT sensor DTCs can indicate that the thermostat is not operating correctly or that the engine coolant level is not filled to specification, producing above normal operating temperatures.

Diagnostic procedure

STEP

INSPECTION

ACTION
1
VERIFY FREEZE FRAME DATA HAS BEEN RECORDED
•  Has FREEZE FRAME DATA been recorded?
Yes
Go to the next step.
No
Record FREEZE FRAME DATA on the repair order, then go to the next step.
2
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.
3
VERIFY RELATED PENDING CODE OR STORED DTCs
•  Turn the ignition switch off then to the ON position (Engine off).
•  Verify related pending code or stored DTCs.
•  Is other DTCs present?
Yes
Go to the appropriate DTC troubleshooting.
(See DTC TABLE [MZI-3.7 (PCM CONNECTOR (2 TYPES))].)
No
Go to the next step.
4
INSPECT GAS LEAKAGE OF EXHAUST SYSTEM
•  Visually inspect for exhaust gas leakage in exhaust system.
•  Are there gas leakage?
Yes
Repair or replace malfunctioning exhaust parts, then go to Step 7.
No
Go to the next step.
5
INSPECT INSTALLATION OF FRONT AND REAR HO2S
•  Inspect for looseness of front and rear HO2Ss.
•  Are they it normal?
Yes
Go to the next step.
No
Retighten sensor, then go to Step 7.
6
INSPECT TWC
•  Clear the DTC using the M-MDS.
•  Cycle the ignition switch off then back to the ON position.
•  Inspect the TWC.
•  Is it normal?
Yes
Go to the next step.
No
Replace the TWC, then go to the next step.
7
VERIFY TROUBLESHOOTING OF DTC P0420, P0430 HAS BEEN COMPLETED
•  Verify that all disconnected connectors are reconnected.
•  Turn the ignition switch to the ON position (Engine off).
•  Clear the DTC from the PCM memory using the M-MDS.
•  Start the engine and run it at idle.
•  Retrieve DTCs using the M-MDS.
•  Is the PENDING CODE for this DTC present?
Yes
Replace the PCM, then go to the next step.
(See PCM REMOVAL/INSTALLATION [MZI-3.7].)
No
Go to the next step.
8
VERIFY AFTER REPAIR PROCEDURE
•  Perform the “AFTER REPAIR PROCEDURE”.
•  Are any DTC present?
Yes
Go to the applicable DTC inspection.
(See DTC TABLE [MZI-3.7 (PCM CONNECTOR (2 TYPES))].)
No
Troubleshooting completed.