DTC P2000: NOX Adsorptive Catalyst System Efficiency Below Threshold (M/T model): General Description
The NOx adsorptive three way catalyst (TWC) absorbs NO2 when the oxygen concentration is high (lean), and it releases absorbed NO2 to oxidize the remaining elements (HC, CO, etc.) in the exhaust gas when the oxygen concentration is low (rich). The NOx adsorptive TWC is considered faulty if the capacity of the NOx adsorbent has deteriorated. The NOx adsorptive TWC absorbs NO2 during lean-burn running. The absorbed NO2 is released when the air/fuel ratio becomes rich, then eventually, the air/fuel ratio downstream of the NOx adsorptive TWC is rich. Based on the third HO2S output after a set time has elapsed since the secondary HO2S indicates "rich", the engine control module (ECM) detects a malfunction and stores a DTC.
MONITOR DESCRIPTION CHART
| Execution | Once per driving cycle | ||
| Sequence | Secondary HO2S | ||
| Duration | 50 seconds(1) or less | ||
| DTC Type | Two drive cycles, MIL ON | ||
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ENABLE CONDITIONS CHART
| Condition | Minimum | Maximum | |
|---|---|---|---|
| Elapsed time after starting the engine | 10 minutes, 5 seconds | - | |
| Engine coolant temperature | 168°F (76°C) | - | |
| Engine speed | 1,500 rpm | 2,600 rpm | |
| MAP value | 35 kPa (260 mmHg, 10.3 in.Hg) | 99 kPa (736 mmHg, 29.0 in.Hg) | |
| The difference between atmospheric pressure and manifold absolute pressure | 1,500 rpm | 8 kPa (54 mmHg, 2.2 in.Hg) | - |
| 2,600 rpm | 11 kPa (81 mmHg, 3.2 in.Hg) | ||
| Vehicle speed | 25 mph (40 km/h) | - | |
| Short term fuel trim | - | 0.98 | |
| Secondary HO2S output voltage | - | 0.29 V | |
| Fuel feedback | During lean burn running | ||
| Monitoring priority | EVAP | ||
| No active DTCs | ECM, A/F Sensor, A/F Sensor Heater, Secondary HO2S Heater, Third HO2S Heater, MAP, CKP, ECT, TP, EGR, BARO, VSS, VTEC System, Fuel System, EVAP | ||
| Others | Must be in 3rd, 4th, or 5th gear | ||
| The duration of lean burn running must be sufficient (at least 1 minute) | |||
| The IMA battery indicates at least 25 % | |||
| The NOx adsorptive TWC is not contaminated by sulfur in the gasoline | |||