This is very rare but it has been reported in the past. There are countless reasons why the check engine light might pop on that could be unrelated to the use of Oxytane.

This engine light is an important part of your vehicle’s on-board diagnostic system. Your car’s computer will illuminate the warning whenever it detects a problem that could increase tailpipe emissions. There’s no way to say exactly why your check engine light is illuminated without performing diagnostic work. However, we have extensively looked into this issue with regards to any possible connections with the use of Oxytane and 2 things are possible.

If the engine was particularly dirty before using Oxytane, Oxytane will clean this excess carbon build up via the combustion process and your exhaust system. This could create a short term spike in the amount of fumes being expelled through the cars exhaust during this initial cleaning phase. The increase in fumes could be detected by various onboard sensors and could trigger the engine warning light to come on. After some time however, the engine will be restored back to it’s new and clean state and the fumes will be eradicated. If this is the case the best thing to do is to continue driving with Oxytane for an additional 1-2 full tanks to fully clean out the engine. After this it is possible for a mechanic to clear the warning light and it should remain off. If the light comes back on again after continuous use with Oxytane its is highly likely that there is another unrelated issue with your vehicle.

Another possibility on more modern cars is a conflict in the engines ECU. When using Oxytane more milage is gained through a cleaner denser fuel burn. These levels can sometimes go above and beyond the manufacturers expectations and since the onboard computers are not used to detecting higher milage rates it can cause the onboard computer to trigger the check engine light with an unknown error code.