MONITOR DESCRIPTION
The ECM uses air fuel ratio 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 (sensor 1), sends pre-catalyst information to the ECM. The second sensor, the air fuel ratio sensor (sensor 2), 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 output current of the air fuel ratio sensor (sensor 2) 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 air fuel ratio sensor (sensor 2) is long, the oxygen storage capacity is great. There is a direct correlation between the air fuel ratio sensor (sensor 2) 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 (1 trip detection logic). |
| Comes on | DTC stored | SAE Code: P0420 |
CATALYST LOCATION
*1 | Air Fuel Ratio Sensor (Sensor 1) | *2 | Air Fuel Ratio Sensor (Sensor 2) |
*3 | Exhaust Manifold | *4 | Front Exhaust Pipe Assembly |
*5 | Center Exhaust Pipe Assembly | *6 | Tail Exhaust Pipe Assembly |
*7 | TWC: Front Catalyst | *8 | TWC: Rear Catalyst |
NOTICE:
When replacing the exhaust manifold (*3) and the front exhaust pipe assembly (*4) in order to replace the three-way catalytic converter, it is not necessary to replace the air fuel ratio sensor (sensor 1) (*1) and the air fuel ratio sensor (sensor 2) (*2).
MONITOR STRATEGY
Related DTCs | P0420: Catalyst deterioration |
Required Sensors/Components (Main) | Air fuel ratio sensor (sensor 1) Air fuel ratio sensor (sensor 2) |
Required Sensors/Components (Related) | Intake air temperature sensor Mass air flow meter sub-assembly Crankshaft position sensor Engine coolant temperature sensor |
Frequency of Operation | Once per driving cycle |
Duration | Approximately 30 seconds |
MIL Operation | Immediate |
Sequence of Operation | None |
TYPICAL ENABLING CONDITIONS
Monitor runs whenever the following DTCs are not stored | P0010, P1360, P1362, P1364, P1366, P2614 (Motor drive VVT system control module) P0011 (VVT system - advance) P0012 (VVT system - retard) P0013 (Exhaust VVT oil control solenoid) P0014 (Exhaust VVT system - advance) P0015 (Exhaust VVT system - retard) P0016 (VVT system - misalignment) P0017 (Exhaust VVT system - misalignment) P0031, P0032, P101D (Air fuel ratio sensor (sensor 1) heater) P0037, P0038, P102D (Air fuel ratio sensor (sensor 2) heater) P005D, P014C, P014D, P015A, P015B, P2195, P2196, P2237, P2238, P2239, P2252, P2253 (Air fuel ratio sensor (sensor 1)) P0087, P0088, P0191, P0192, P0193 (Fuel pressure sensor (for high pressure side)) P0101, P0102, P0103 (Mass air flow meter) P0106, P0107, P0108 (Manifold absolute pressure) P0111, P0112, P0113 (Intake air temperature sensor) P0116, P0117, P0118 (Engine coolant temperature sensor) P0121, P0122, P0123, P0222, P0223, P2135 (Throttle position sensor) P0125 (Insufficient coolant temperature for closed loop fuel control) P0128 (Thermostat) P0136, P013A, P2270, P2271, P22AB, P22AC, P22AD, P22B3, P22B4 (Air fuel ratio sensor (sensor 2)) P0171, P0172 (Fuel system) P0201, P0202, P0203, P0204, P062D, P21CF, P21D0, P21D1, P21D2 (Fuel injector) P0300, P0301, P0302, P0303, P0304 (Misfire) P0327, P0328 (Knock control sensor) P0335, P0337, P0338 (Crankshaft position sensor) P0340, P0342, P0343 (Camshaft position sensor) P0365, P0367, P0368 (Exhaust camshaft position sensor) P0401 (EGR system (closed)) P0489, P0490 (EGR control circuit) P0657, P0658, P2102, P2103, P2111, P2112, P2119 (Throttle actuator) P107B, P107C, P107D (Fuel pressure sensor (for low pressure side)) P11EA, P11EC, P11ED, P11EE, P11EF, P219A, P219C, P219D, P219E, P219F (Air-fuel ratio imbalance) P1235 (High pressure fuel pump circuit) P2228, P2229 (Atmospheric pressure sensor) |
Response rate during fuel cut from rich condition | Completed |
Auxiliary 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 psi(abs)] or higher |
Idling | Off |
Engine speed | Less than 4000 rpm |
Sub feedback control | Executing |
Air fuel ratio sensor (sensor 1) status | Activated |
Fuel system status | Closed loop |
Engine load | 10% or higher, and less than 80% |
All of the following conditions are met | 1, 2 and 3 |
1. Mass air flow | 2.9 gm/sec or more, and less than 60 gm/sec |
2. Front catalyst temperature (estimated) | 520°C (968°F) or higher, and less than 820°C (1508°F) |
3. Rear catalyst temperature (estimated) | 400°C (752°F) or higher, and less than 700°C (1292°F) |
TYPICAL MALFUNCTION THRESHOLDS
Oxygen Storage Capacity (OSC) of catalyst (Normalized) | Less than 1 |
MONITOR RESULT
Refer to detailed information in Checking Monitor Status.
Click here
P0420: Catalyst Efficiency / O2 STORAGE B1 Monitor ID | Test ID | Scaling | Unit | Description |
---|---|---|---|---|
$21 | $AF | Multiply by 0.001 | No dimension | Oxygen storage capacity of catalyst bank 1 (Normalization) |
CONFIRMATION DRIVING PATTERN
HINT:
Click here
Click here
Click here
HINT:
In order to keep the idle stable, turn the A/C and all other electric loads off and do not perform any shift operations.
CAUTION:
When performing the confirmation driving pattern, obey all speed limits and traffic laws.
HINT:
CAUTION:
When performing the confirmation driving pattern, obey all speed limits and traffic laws.
HINT:
If the engine stops, further depress the accelerator pedal to restart the engine.
HINT:
Click here
CAUTION:
When performing the confirmation driving pattern, obey all speed limits and traffic laws.
HINT:
HINT:
The normal judgment procedure is used to complete DTC judgment and also used when clearing permanent DTCs.
CAUTION:
When performing the confirmation driving pattern, obey all speed limits and traffic laws.
HINT:
HINT:
If the monitor item does not change to Complete, and no DTCs are stored, extend the driving time.
Techstream Display | Description |
---|---|
NORMAL |
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ABNORMAL |
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INCOMPLETE |
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HINT:
The normal judgment procedure is used to complete DTC judgment and also used when clearing permanent DTCs.
CAUTION / NOTICE / HINT
NOTICE:
Click here
(Select Powertrain in Health Check and then check the time stamp data.)
Click here
Click here
HINT:
PROCEDURE
1. | CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P042000) |
(a) Connect the Techstream to the DLC3.
(b) Turn the power switch on (IG).
(c) Turn the Techstream on.
(d) Enter the following menus: Powertrain / Engine / Trouble Codes.
(e) Read the DTCs.
Powertrain > Engine > Trouble Codes Result | Proceed to |
---|---|
DTC P042000 is output | A |
DTC P042000 and other DTCs are output | B |
HINT:
If any DTCs other than P042000 are output, troubleshoot those DTCs first.
B | GO TO DTC CHART |
|
2. | PERFORM ACTIVE TEST USING TECHSTREAM (CONTROL THE INJECTION VOLUME FOR A/F SENSOR) |
(a) Connect the Techstream to the DLC3.
(b) Turn the power switch on (IG).
(c) Turn the Techstream on.
(d) Put the engine in Inspection Mode (Maintenance Mode).
Powertrain > Hybrid Control > Utility Tester Display |
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Inspection Mode |
(e) Start the engine and warm it up until the engine coolant temperature is 75°C (167°F) or higher.
(f) Idle the engine for 5 minutes or more with the shift lever in P.
(g) Enter the following menus: Powertrain / Engine / Active Test / Control the Injection Volume for A/F Sensor / Data List / Coolant Temperature, A/F (O2) Sensor Current B1S1 and A/F (O2) Sensor Current B1S2.
Powertrain > Engine > Active Test Active Test Display |
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Control the Injection Volume for A/F Sensor |
Data List Display |
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Coolant Temperature |
A/F (O2) Sensor Current B1S1 |
A/F (O2) Sensor Current B1S2 |
(h) Change the fuel injection volume using the Techstream, and monitor the output current of the air fuel ratio sensor (sensor 1) (A/F (O2) Sensor Current B1S1) and air fuel ratio sensor (sensor 2) (A/F (O2) Sensor Current B1S2) displayed on the Techstream.
HINT:
Standard:
Techstream Display (Sensor) | Injection Volume | Status | Current |
---|---|---|---|
A/F (O2) Sensor Current B1S1 (Air fuel ratio (sensor 1)) | 12.5% | Rich | Below -0.075 mA |
-12.5% | Lean | More than 0.037 mA | |
A/F (O2) Sensor Current B1S2 (Air fuel ratio (sensor 2)) | 12.5% | Rich | Below -0.86 mA |
-12.5% | Lean | More than 0.33 mA |
Status A/F (O2) Sensor Current B1S1 | Status A/F (O2) Sensor Current B1S2 | Actual air fuel ratio, air fuel ratio sensor (sensor 1) and air fuel ratio sensor (sensor 2) condition | Main Suspected Trouble Area | Proceed to |
---|---|---|---|---|
Lean/Rich | Lean/Rich | Normal |
| A |
Lean | Lean/Rich | Air fuel ratio sensor (sensor 1) malfunction |
| B |
Rich | Lean/Rich | Air fuel ratio sensor (sensor 1) malfunction |
| |
Lean/Rich | Lean | Air fuel ratio sensor (sensor 2) malfunction |
| C |
Lean/Rich | Rich | Air fuel ratio sensor (sensor 2) malfunction |
| |
Lean | Lean | Actual air fuel ratio lean |
| D |
Rich | Rich | Actual air fuel ratio rich |
|
HINT:
Refer to "Data List / Active Test" [A/F (O2) Sensor Current B1S1, A/F (O2) Sensor Current B1S2].
Click here
B | GO TO STEP 6 |
C | GO TO STEP 7 |
D | GO TO STEP 9 |
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3. | CHECK FOR EXHAUST GAS LEAK |
(a) Check for exhaust gas leaks.
OK:
No gas leaks in exhaust system.
NG | GO TO STEP 13 |
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4. | PERFORM ACTIVE TEST USING TECHSTREAM (CONTROL THE EGR STEP POSITION) |
(a) Connect the Techstream to the DLC3.
(b) Turn the power switch on (IG).
(c) Turn the Techstream on.
(d) Put the engine in Inspection Mode (Maintenance Mode).
Powertrain > Hybrid Control > Utility Tester Display |
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Inspection Mode |
(e) Start the engine and warm it up until the engine coolant temperature is 75°C (167°F) or higher.
HINT:
The A/C switch and all accessories should be off.
(f) Enter the following menus: Powertrain / Engine / Active Test / Control the EGR Step Position / Data List / Intake Manifold Absolute Pressure, Coolant Temperature and Engine Independent.
Powertrain > Engine > Active Test Active Test Display |
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Control the EGR Step Position |
Data List Display |
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Intake Manifold Absolute Pressure |
Coolant Temperature |
Engine Independent |
(g) Confirm that the value of Data List item Engine Independent is "Operate" then check the value of Intake Manifold Absolute Pressure while performing the Active Test.
NOTICE:
OK:
The value of Intake Manifold Absolute Pressure changes in response to the EGR step position when the value of Engine Independent is "Operate".
Standard:
- | Control the EGR Step Position (Active Test) | |
---|---|---|
0 Steps | 0 to 30 Steps | |
Intake Manifold Absolute Pressure (Data List) | (EGR valve is fully closed) | Intake Manifold Absolute Pressure value is at least +10 kPa (1.45 psi) higher than when EGR valve is fully closed |
HINT:
OK | GO TO STEP 16 |
|
5. | INSPECT EGR VALVE ASSEMBLY |
(a) Remove the EGR valve assembly.
Click here
(b) Check if the EGR valve is stuck open.
OK:
EGR valve is tightly closed.
HINT:
Perform "Inspection After Repair" after replacing the EGR valve assembly.
Click here
OK | GO TO STEP 16 |
NG | REPLACE EGR VALVE ASSEMBLY |
6. | REPLACE AIR FUEL RATIO SENSOR (SENSOR 1) |
(a) Replace the air fuel ratio sensor (sensor 1).
Click here
HINT:
Perform "Inspection After Repair" after replacing the air fuel ratio sensor (sensor 1).
Click here
NEXT | GO TO STEP 14 |
7. | CHECK FOR EXHAUST GAS LEAK |
(a) Check for exhaust gas leaks.
OK:
No gas leaks in exhaust system.
NG | GO TO STEP 13 |
|
8. | REPLACE AIR FUEL RATIO SENSOR (SENSOR 2) |
(a) Replace the air fuel ratio sensor (sensor 2).
Click here
HINT:
Perform "Inspection After Repair" after replacing the air fuel ratio sensor (sensor 2).
Click here
NEXT | GO TO STEP 14 |
9. | CHECK FOR EXHAUST GAS LEAK |
(a) Check for exhaust gas leaks.
OK:
No gas leaks in exhaust system.
NG | GO TO STEP 13 |
|
10. | PERFORM ACTIVE TEST USING TECHSTREAM (CONTROL THE EGR STEP POSITION) |
(a) Connect the Techstream to the DLC3.
(b) Turn the power switch on (IG).
(c) Turn the Techstream on.
(d) Put the engine in Inspection Mode (Maintenance Mode).
Powertrain > Hybrid Control > Utility Tester Display |
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Inspection Mode |
(e) Start the engine and warm it up until the engine coolant temperature is 75°C (167°F) or higher.
HINT:
The A/C switch and all accessories should be off.
(f) Enter the following menus: Powertrain / Engine / Active Test / Control the EGR Step Position / Data List / Intake Manifold Absolute Pressure, Coolant Temperature and Engine Independent.
Powertrain > Engine > Active Test Active Test Display |
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Control the EGR Step Position |
Data List Display |
---|
Intake Manifold Absolute Pressure |
Coolant Temperature |
Engine Independent |
(g) Confirm that the value of Data List item Engine Independent is "Operate" then check the value of Intake Manifold Absolute Pressure while performing the Active Test.
NOTICE:
OK:
The value of Intake Manifold Absolute Pressure changes in response to the EGR step position when the value of Engine Independent is "Operate".
Standard:
- | Control the EGR Step Position (Active Test) | |
---|---|---|
0 Steps | 0 to 30 Steps | |
Intake Manifold Absolute Pressure (Data List) | (EGR valve is fully closed) | Intake Manifold Absolute Pressure value is at least +10 kPa (1.45 psi) higher than when EGR valve is fully closed |
HINT:
OK | GO TO STEP 12 |
|
11. | INSPECT EGR VALVE ASSEMBLY |
(a) Remove the EGR valve assembly.
Click here
(b) Check if the EGR valve is stuck open.
OK:
EGR valve is tightly closed.
HINT:
Perform "Inspection After Repair" after replacing the EGR valve assembly.
Click here
NG | REPLACE EGR VALVE ASSEMBLY |
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12. | CHECK CAUSE OF EXTREMELY RICH OR LEAN ACTUAL AIR FUEL RATIO |
(a) Check the cause of extremely rich or lean actual air fuel ratio, referring to the DTC P017100 and P017200 Inspection Procedure.
Click here
NEXT | GO TO STEP 14 |
13. | REPAIR OR REPLACE EXHAUST SYSTEM |
(a) Repair or replace exhaust system.
HINT:
Perform "Inspection After Repair" after repairing or replacing the exhaust system.
Click here
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14. | CLEAR DTC |
(a) Connect the Techstream to the DLC3.
(b) Turn the power switch on (IG).
(c) Turn the Techstream on.
(d) Clear the DTCs.
Powertrain > Engine > Clear DTCs(e) Turn the power switch off and wait for at least 30 seconds.
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15. | CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED |
(a) Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.
(b) Enter the following menus: Powertrain / Engine / Trouble Codes.
(c) Read the DTCs.
Powertrain > Engine > Trouble Codes Result | Proceed to |
---|---|
DTCs are not output | A |
DTC P042000 is output | B |
A | END |
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16. | REPLACE EXHAUST MANIFOLD (TWC: FRONT CATALYST) AND FRONT EXHAUST PIPE ASSEMBLY (TWC: REAR CATALYST) |
NOTICE:
When replacing the exhaust manifold and the front exhaust pipe assembly in order to replace the three-way catalytic converter, it is not necessary to replace the air fuel ratio sensor (sensor 1) and the air fuel ratio sensor (sensor 2).
HINT:
Confirm the replacement parts, referring to the illustration in the Catalyst Location.
(a) Replace the exhaust manifold (TWC: Front catalyst).
Click here
(b) Replace the front exhaust pipe assembly (TWC: Rear catalyst).
Click here
NEXT | END |