Monitor Description
The ECM uses the diagnosis value to determine catalyst deterioration. If the diagnostic value exceeds the standard value, the ECM determines that there is catalyst degradation, illuminates the MIL, and stores the DTC.
The diagnosis value is calculated based on the catalyst monitor value (CM) which is determined from the amount of change in the air/fuel ratio sensor λvalue and oxygen sensor value, as well as the reaction rate determined during oxygen sensor reaction time.
MONITOR STRATEGY
| Related DTCs | P0420: Catalyst monitor with sufficient sensor performance for other monitors functional check |
| Required Sensors/Components (Main) | Air/fuel ratio and oxygen sensors |
| Required Sensors/Components (Related) | Intake air temperature sensor, intake air flow meter SUB-ASSY, vacuum sensor, crankshaft position sensor, and E.F.I. water temperature sensor |
| Frequency of Operation | Once per driving cycle |
| Duration | 30 to 55 seconds |
| MIL Operation | 2 operation cycle |
| Sequence of Operation | None |
TYPICAL ENABLING CONDITIONS
| Overlap prohibited DTC | P0030, P0031, P0032 (air/fuel ratio sensor - heater) P0037, P0038 (oxygen sensor - heater) P0068, P0107, P0108 (Vacuum (MAP) sensor) P0101, P0102, P0103 (intake air flow (MAF) meter) P0111, P0112, P0113 (Intake Air Temperature (IAT) sensor) P0117, P0118, P0125 (Engine Coolant Temperature (ECT) sensor) P0122, P0123, P0222, P0223 (Throttle position sensor) P0131, P0132 (air/fuel ratio sensor - ECM input voltage) P0134, P2195, P2196 (Air/fuel ratio sensor - Output voltage) P0137, P0138 (oxygen sensor - lack of continuity in circuit) P0140 (oxygen sensor - output voltage) P0461, P0462, P0463 (Fuel Level sensor (FL)) P0500 (Vehicle Speed Sensor (VSS)) P0604, P0605 (ECM ROM) P1160 (throttle return spring) P2096, P2097 (Post-catalyst fuel trim system) P2101, P2102 (Throttle actuator control motor) P2109 (Throttle position sensor minimum stop) P2119 (Throttle actuator control) P2122, P2123, P2127, P2128 (Accelerator Pedal Position Sensor (APPS) circuit) P2135 (Throttle position sensor (TPS) degree of correlation) P2138 (Accelerator pedal position sensor (APPS) degree of correlation) |
| Engine coolant temperature | 60°C {140°F} or more |
| Battery Voltage | 10.9V or more |
| F/B operation condition | Closed loop |
| Intake amount per second | 5 g/sec or more, and less than 30 g/sec |
| Catalyst estimated exhaust gas temperature | 440°C {824°F} or less |
| Elapsed time (Difference between actual and target λ< 0.15) |
1 seconds |
| Vehicle speed | More than 40km/h {24.9 MPH} |
| Fluctuation in intake amount during half engine cycle | Less than 0.02g/rev |
| Variation in oxygen sensor output, after the fuel is cut off, from rich to lean | Experienced |
| EVAP system monitor | Control not in progress |
| Total canister purge time after starting the engine | 35 seconds or more |
| EVAP density learning value during a purge | Less than 0.2 |
| Secondary Oxygen sensor element estimated temperature | 500°C {932°F} or more |
| Total intake amount per second | 1300 g or more (May change due to an air temperature different than estimated) |
| Atmospheric pressure | 75.06 kPa {563.09 mmHg, 22.169 inHg, 10.884 psi} or more |
TYPICAL MALFUNCTION THRESHOLDS
| Diagnosis value(1) | 10 or more | ||
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