Document
40 CFR 1036.111 — Diagnostic and inducement requirements
Code of Federal Regulations
Overview
40 CFR 1036.111 specifies diagnostic and inducement requirements for heavy-duty engines, including reduced-power (derate) responses to certain aftertreatment or DEF-related fault conditions.
Repeal relevance: This is the specific regulation producing on-road derates. It is the direct target of the EPA-HQ-OAR-2026-0728 rulemaking.
Operative language
Short paraphrases of the operative text. Read the full section at the source.
40 CFR 1036.111(b)-(c) · Open source
Heavy-duty engines must be equipped with diagnostic systems that detect malfunctions affecting the emission control system, and must implement operator-inducement responses (including reduced-power / derate strategies) when specified fault conditions persist.
Establishes: The on-road derate obligation for heavy-duty engines. Fault conditions the engine must respond to include DEF quality/quantity, NOx sensor malfunctions, and other aftertreatment faults.
Plain English: This is the specific regulation that causes trucks to lose power on-highway after certain faults. It is the direct target of EPA's 2026 inducement rulemaking (EPA-HQ-OAR-2026-0728).