Cold Start Emission Reduction Monitor

Cold Start Emission Reduction Monitor

Overview

The cold start emission reduction monitor is an on-board strategy designed for vehicles that meet the low emissions vehicle-II (LEV-II) emissions standards. The monitor works by detecting the lack of catalyst warm up resulting from a failure to apply sufficient cold start emission reduction during a cold start.

Cold Start Emission Reduction System Monitor

The PCM uses the cold start emission reduction system monitor to calculate the actual catalyst warm up temperature during a cold start. The actual catalyst warm up temperature calculation uses measured engine speed, measured air mass and commanded spark timing inputs to the PCM. The PCM then compares the actual temperature to the expected catalyst temperature model. The expected catalyst temperature model calculation uses desired engine speed, desired air mass and desired spark timing inputs to the PCM. The difference between the actual and expected temperatures is reflected in a ratio. This ratio is a measure of how much loss of catalyst heating occurred over the period of time and when compared with a calibrated threshold it helps the PCM to determine if the cold start emission reduction system is working properly. This ratio correlates to tailpipe emissions, and a malfunction indicator lamp (MIL) illuminates when the calibrated threshold is exceeded. The monitor is disabled if a concern is present in any of the sensors or systems used for expected catalyst temperature model calculation.

Cold start emission reduction system monitor test operation

- DTC: P050E cold start engine exhaust temperature out of range
- Monitor execution: once per driving cycle, from start up with the cold start emission reduction monitor active
- Monitor sequence: the monitor collects data during first 15 seconds of the cold start
- Monitoring duration: the monitor completes 300 seconds after initial engine start
Cold start emission reduction system monitor entry conditions

- Engine coolant temperature at the start of the monitor is between 1.67°C (35°F) and 37.78°C (100°F)
- Barometric pressure is above 74.5 kPa (22 in-Hg)
- Catalyst temperature at the start of the monitor is between 1.67°C (35°F) and 51.67°C (125°F)
- Fuel level is above 15%