P0420
DTC P0420 (LAT) (2.4L Hybrid)
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides an overview of each diagnostic category.
DTC Descriptor
DTC P0420
- Catalyst System Low Efficiency Bank 1
Circuit/System Description
Note: A new converter with less than 100 miles on it may set DTC P0420 due to out-gassing of the internal matting. Operating the vehicle at highway speeds for approximately 1 hour may correct the condition.
A 3-way catalytic converter (TWC) controls emissions by converting hydrocarbons (HC) and carbon monoxide (CO) into carbon dioxide (CO2), and oxides of nitrogen (NOx) into nitrogen. The TWC also stores oxygen. The engine control module (ECM) monitors this oxygen storage capacity by comparing the pre and post-catalyst oxygen sensor signals while adding and subtracting fuel during specific deceleration fuel cut-off (DFCO) conditions. The ECM compares the pre and post-catalyst oxygen sensor signals to determine if the oxygen storage capacity of the catalyst is degraded.
Conditions for Running the DTC
1. Driving Conditions
* DTCs P0030, P0036, P0068, P0106, P0107, P0108, P0112, P0113, P0117, P0118, P0120, P0121, P0122, P0123, P0130, P0131, P0132, P0133, P0134, P0135, P0136, P0137, P0138, P0140, P0141, P0171, P0172, P0201, P0202, P0203, P0204, P0220, P0300, P0315, P0326, P0327, P0336, P0340, P0341, P0442, P0446, P0452, P0453, P0455, P0496, P0502, P0506, P0507, P0601, P0602, P1133, P1516, P1621, P2135, P2138, P2176 are not set.
* The vehicle has been driven at more than 900 RPM for more than 20 seconds above 43 km/h (27 mph).
* The vehicle is in Closed Loop.
* The fuel level is greater than 10 percent.
* The vehicle has Fuel Trim Learn enabled.
* The Engine Coolant Temperature (ECT) parameter is between 70-128°C (158-262°F).
* The Barometric Pressure (BARO) parameter is more than 70 kPa.
* The Catalytic Converter Calculated Temperature parameter is greater than or equal to 500°C (932°F) for more than 1 minute.
* The Intake Air Temperature (IAT) parameter is between -20 and +100°C (-4 and +212°F).
* The battery voltage is more than 11 volts.
2. DFCO Conditions
* The DFCO period is greater than 1.75 seconds.
* The heated oxygen sensor (HO2S) 1 is less than 300 mV prior to DFCO exit.
* The HO2S 2 is less than 300 mV for 2 seconds prior to DFCO exit.
3. DFCO Exit Conditions
* The throttle position (TP) sensor travel is less than 30 percent.
* The equivalence ratio is greater than 1.
Conditions for Setting the DTC
* The ECM has determined the catalyst efficiency has degraded below a calibrated threshold.
* This diagnostic may conclude in one test attempt. However, this diagnostic may require as many as 24 test attempts, which would require at least 3 drive cycles. Each test attempt may conclude within approximately 1 minute.
Action Taken When the DTC Sets
DTC P0420 is a Type A DTC.
Conditions for Clearing the MIL/DTC
DTC P0420 is a Type A DTC.
Reference Information
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions (Diagnostic Trouble Code Descriptions)
Electrical Information Reference
Diagnostic Trouble Code (DTC) List - Vehicle (Diagnostic Trouble Code Descriptions)
Circuit/System Verification
1. Verify that no other DTCs are set.
• If any DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle (Diagnostic Trouble Code Descriptions).
2. Clear the DTCs.
3. Operate the vehicle according to the Driving Conditions within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
4. After the Driving Conditions have been met, drive the vehicle at approximately 80 km/h (50 mph) for 60 seconds.
5. Perform a closed throttle deceleration until the vehicle speed is less then 40 km/h (25 mph).
6. Verify that DTC P0420 has passed this ignition cycle.
• If not passed or failed this ignition cycle, the test aborted resulting in an inconclusive test result. The above test may need to be repeated up to 5 more times during this drive cycle.
Circuit/System Testing
Caution: Refer to Three-Way Catalytic Converter Damage Caution (Service Precautions).
Caution: Refer to Heated Oxygen Sensor Resistance Learn Reset Caution (Heated Oxygen Sensor Resistance Learn Reset Caution).
Note: A new converter with less than 100 miles on it may set DTC P0420 due to out-gassing of the internal matting. Operating the vehicle at highway speeds for approximately 1 hour may correct the condition.
1. Ignition OFF, open the hood to disable the Auto-Stop function. Refer to Hybrid Modes of Operation Description.
2. Ignition ON, verify the scan tool Hood Position parameter displays Open.
• If the Hood Position parameter does not display Open, refer to Diagnostic Trouble Code (DTC) List - Vehicle (Diagnostic Trouble Code Descriptions).
3. Inspect for the following conditions, which may cause a catalytic converter to degrade:
* An engine misfire
* High engine oil or high coolant consumption
* Retarded spark timing
* A weak or poor spark
* A lean fuel mixture
* A rich fuel mixture
* A damaged oxygen sensor or wiring harness
* The catalyst test may abort if the vehicle falls outside the Conditions for Running the DTC.
* A catalyst may be temporarily degraded if a fuel with high sulfur content has been used. Drive the vehicle at highway speeds for 10 minutes and retest the converter.
4. Inspect the catalytic converter for the following conditions:
* Dents
* A severe discoloration caused by excessive temperatures
* Road damage
* An internal rattle caused by damaged catalyst substrate
* Restrictions
• If a condition is found, replace the catalytic converter.
5. Inspect the exhaust system for the following conditions:
* Leaks
* Physical damage
* Loose or missing hardware
* Properly torqued HO2S
* Restrictions
• If a condition is found, repair the exhaust system.
6. Inspect the post catalyst HO2S for the following conditions:
* A grounded wiring harness
* Damage
• If a condition is found, replace the post catalyst HO2S.
7. If all physical conditions test normal, test or replace the catalytic converter.
Repair Instructions
Note: A new converter with less than 100 miles on it may set DTC P0420 due to out-gassing of the internal matting. Operating the vehicle at highway speeds for approximately 1 hour may correct the condition.
* Exhaust Manifold Replacement (LAT and LE5) (Service and Repair)Exhaust Manifold Replacement (LE5 With MH8) (Service and Repair)
* Exhaust Manifold Pipe Replacement (LE5)
* Heated Oxygen Sensor 2 Replacement (LAT and LE5) (Service and Repair)
* Exhaust Leakage (Exhaust Leakage)
* Restricted Exhaust (Restricted Exhaust)
Repair Verification
1. Clear the DTCs.
2. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
3. After the conditions for running the DTC have been met, drive the vehicle at approximately 80 km/h (50 mph) for 60 seconds.
4. Perform a closed throttle deceleration until the vehicle speed is less then 40 km/h (25 mph).
5. Verify that DTC P0420 has passed this ignition cycle.
• If not passed or failed this ignition cycle, the test aborted resulting in an inconclusive test result. The above test may need to be repeated up to 5 more times during this drive cycle.