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On-Board Diagnostics: Monitors
- Comprehensive Component Monitor
- Monitors ECM systems for opens, shorts grounds and out-of-range sensors. Also monitors rationality of sensors. Rationality is whether the sensor value is consistent with the operating conditions of the other sensors.
- Misfire Monitor
- Monitors engine misfire using crankshaft sensor to determine location and severity of misfire. A catalyst damaging misfire will flash the MIL, and a non-catalyst damaging misfire is a normal type "B" code.
- Fuel Trim Monitor
- Monitors short and long term fuel trim for being at maximum lean or rich limit.
- Oxygen Sensor Monitor
- Monitors all oxygen sensors for maximum voltage level, minimum voltage level and lean rich/rich lean switching rate.
- Oxygen Sensor Heater Monitor
- Monitors oxygen sensor heater by watching sensor's time-to-activity after a cold start.
- Catalyst Monitor
- Monitors catalyst efficiency by comparing activity rate of pre-catalyst oxygen sensor and post-catalyst oxygen sensor.
- EVAP Monitor
- Monitors EVAP system for large leaks, small leaks and purge flow.