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For some emissions-related repairs like oxygen sensors and catalytic converters, a lot of time can be spent confirming the repair by trying to complete the vehicle emissions monitors. To complete or force a monitor requires driving the vehicle under specific conditions. The emissions drive cycle might include getting the vehicle to closed loop operation and performing four or five periods of accelerating from 30 to 45 miles an hour. Other manufacturers might require driving at freeway speeds. 

One of the most challenging monitors to complete is the catalyst monitor. This monitor is tracking the signals from the upstream and downstream oxygen sensors to determine if the catalyst is operating efficiently and reducing hydrocarbon and other combustion byproducts into less environmentally harmful compounds. If the catalyst is underperforming, it might be a sign the catalyst is contaminated or damaged by a component upstream. 

The engine management system will grade the catalytic converter using the two oxygen sensors and give it an efficiency score. If the efficiency is below a set threshold, it could prevent the catalytic converter monitor from completing. If the efficiency score is low enough, it will set an efficiency code like P0420. Even a pending P0420 code will prevent the oxygen sensor and even EVAP monitors from completing, and you drove around for nothing.  

There is no wiggle room for the catalytic converter efficiency scores. These numbers are set in stone, and every percentage point matters. To tip the scales to your advantage when trying to complete an emissions monitor drive cycle, you can use all the help you can get.  

Rislone’s CAT COMPLETE Fuel, Exhaust & Emissions System Cleaner has high-performing detergents and heavy-duty cleaning solvents that effectively scrub and remove contaminants, soot, carbon build-up, and oily residue from the fuel injectors, combustion chambers, turbo, EGR, catalytic converters, oxygen sensors and the exhaust system. These, along with other active chemical agents, react with the gases created in the combustion process to remove the remaining inorganic deposits. This process restores their function and with regular use maintains efficiency. 

The next time you are trying to complete the emission readiness monitor, try a bottle of Rislone’s CAT COMPLETE to make your post-emissions repair test drive as productive as possible.