The EPA has been taking a hatchet to emission regulations, which “don’t mean a damn bit of difference to the environment” according to “Home Alone 2” actor, President Donald Trump. EPA Administrator Lee Zeldin just announced the latest chop at the Iowa State Fair, demanding the elimination of speed and power reduction limp modes when diesel engines run low on diesel exhaust fluid (DEF) starting with 2027 model year trucks. He also strongly urges manufacturers to update older trucks to eliminate this nagware.
Admittedly, it’s quite annoying to have your truck nerf itself just because you haven’t kept the AdBlue fluid topped off. But the annoyance is the point. DEF mixes with the gases in a diesel engine’s exhaust to reduce harmful nitrogen oxide (NOx) emissions. This helps prevent smog and acid rain, according to the EPA website, unless they’ve scrubbed this information by the time you read it. Asthma sufferers are particularly vulnerable to breathing difficulties from NOx emissions, but I don’t think any of us enjoy breathing dark clouds of smoke from a truck that’s rolling coal.
Breaking the law, breaking the law
These new regulations actually violate the EPA’s requirements already on the books for diesel vehicles using DEF. From the EPA’s own website, one such requirement is:
- Tamper Prevention System: The system must be designed to prevent tampering or bypassing DEF usage.
However, the EPA’s new guidance to eliminate annoying speed limiters and power reductions effectively tampers with the tamper prevention system. Is there anything preventing drivers from simply not using DEF anymore? When I lived in the north, I drove all winter with the TPMS warning light on because I was too cheap to buy tire pressure sensors for my winter wheel and tire set. Similarly, a dashboard warning light for low DEF isn’t going to stop anyone from running without it, effectively bypassing DEF usage against EPA regulations. Such a warning would probably fail a state emission test, but it’s simple enough to add just enough DEF to shut it off, then not refill until the next inspection.
I don’t like the idea of a diesel vehicle holding itself ransom until you comply with its demands. However, I do like breathing clean air, not having smog or acid rain, and not suffering from an asthma attack when riding my motorcycle behind a diesel truck. Sadly, I don’t think we can trust drivers to do the right thing without some sort of penalty, especially if what we’re asking them to do is inconvenient.