Section 1036.125 - Maintenance instructions and allowable maintenanceMaintenance includes any inspection, adjustment, cleaning, repair, or replacement of components and is classified as either emission-related or not emission-related and each of these can be classified as either scheduled or unscheduled. Further, some emission-related maintenance is also classified as critical emission-related maintenance. Give the ultimate purchaser of each new engine written instructions for maintaining and using the engine. As described in paragraph (h) of this section, these instructions must identify how owners properly maintain and use engines to clarify responsibilities for regulatory requirements such as emission-related warranty and defect reporting.
(a)Critical emission-related maintenance. Critical emission-related maintenance includes any adjustment, cleaning, repair, or replacement of components listed in paragraph (a)(2) of this section. Critical emission-related maintenance may also include other maintenance that you determine is critical, including maintenance on other emission-related components as described in 40 CFR part 1068, appendix A, if we approve it in advance. You may perform scheduled critical emission-related maintenance during service accumulation on your emission-data engines at the intervals you specify.(1)Maintenance demonstration. You must demonstrate that the maintenance is reasonably likely to be done at your recommended intervals on in-use engines. We will accept DEF replenishment as reasonably likely to occur if your engine meets the specifications in § 1036.111 . We will accept other scheduled maintenance as reasonably likely to occur if you satisfy any of the following conditions: (i) You present data showing that, if a lack of maintenance increases emissions, it also unacceptably degrades the engine's performance.(ii) You design and produce your engines with a system we approve that displays a visible signal to alert drivers that maintenance is due, either as a result of component failure or the appropriate degree of engine or vehicle operation. The signal must clearly display "maintenance needed", "check engine", or a similar message that we approve. The signal must be continuous while the engine is operating and not be easily eliminated without performing the specified maintenance. Your maintenance instructions must specify resetting the signal after completing the specified maintenance. We must approve the method for resetting the signal. You may not design the system to be less effective at the end of the useful life. If others install your engine in their vehicle, you may rely on installation instructions to ensure proper mounting and operation of the display. Disabling or improperly resetting the system for displaying these maintenance-related signals without performing the indicated maintenance violates the tampering prohibition in 42 U.S.C. 7522(a)(3) .(iii) You present survey data showing that at least 80 percent of engines in the field get the maintenance you specify at the recommended intervals.(iv) You provide the maintenance free of charge and clearly say so in your maintenance instructions.(v) You otherwise show us that the maintenance is reasonably likely to be done at the recommended intervals.(2)Minimum scheduled maintenance intervals. You may not schedule critical emission-related maintenance more frequently than the minimum intervals specified or allowed in this paragraph (a), except as specified in paragraph (g) of this section. The minimum intervals specified for each component applies to actuators, sensors, tubing, valves, and wiring associated with that component, except as specified. Table 1 to Paragraph (a)(2) of § 1036.125 -Minimum Scheduled Maintenance Intervals for Replacement in Miles (or Hours)
| Components | Spark-ignition HDE | Light HDE | Medium HDE | Heavy HDE |
| Spark plugs | 25,000 (750) | | | |
| DEF filters | | 100,000 (3,000) | 100,000 (3,000) | 100,000 (3,000) |
| Crankcase ventilation valves and filters | 60,000 (1,800) | 60,000 (1,800) | 60,000 (1,800) | 60,000 (1,800) |
| Ignition wires and coils | 50,000 (1,500) | | | |
| Oxygen sensors | 80,000 (2,400) | | | |
| Air injection system components | 110,000 (3,300) | | | |
| Sensors, actuators, and related control modules that are not integrated into other systems | 100,000 (3,000) | 100,000 (3,000) | 150,000 (4,500) | 150,000 (4,500) |
| Particulate filtration systems (other than filter substrates) | 100,000 (3,000) | 100,000 3,000) | 250,000 7,500) | 250,000 (7,500) |
| Catalyst systems (other than catalyst substrates), fuel injectors, electronic control modules, hybrid system components, turbochargers, and EGR system components (including filters and coolers) | 110,000 (3,300) | 110,000 (3,300) | 185,000 5,550) | 435,000 (13,050) |
| Catalyst substrates and particulate filter substrates | 200,000 (10,000) | 270,000 (13,000) | 350,000 (17,000) | 650,000 (32,000) |
Table 2 to Paragraph (a)(2) of § 1036.125 -Minimum Scheduled Maintenance Intervals for Adjustment or Cleaning
| Component | Accumulated miles (hours) for components |
| Spark-ignition HDE | Light HDE | Medium HDE | Heavy HDE |
| Spark plugs | 25,000 (750) | | | |
| EGR-related filters and coolers, fuel injectors, and crankcase ventilation valves and filters | 50,000 (1,500) | 50,000 (1,500) | 50,000 (1,500) | 50,000 (1,500) |
| DEF filters | | 50,000 (1,500) | 50,000 (1,500) | 50,000 (1,500) |
| Ignition wires and coils | 50,000 (1,500) | | | |
| Oxygen sensors | 80,000 (2,400) | | | |
| Air injection system components | 100,000 (3,000) | | | |
| Catalyst system components, EGR system components (other than filters or coolers), particulate filtration system components, and turbochargers | 100,000 (3,000) | 100,000 (3,000) | 100,000 (3,000), then 50,000 (4,500) | 100,000 (3,000), then 150,000 (4,500) |
(3)New technology. You may ask us to approve scheduled critical emission-related maintenance of components not identified in paragraph (a)(2) of this section that is a direct result of the implementation of new technology not used in model year 2020 or earlier engines, subject to the following provisions: (i) Your request must include your recommended maintenance interval, including data to support the need for the maintenance, and a demonstration that the maintenance is likely to occur at the recommended interval using one of the conditions specified in paragraph (a)(1) of this section.(ii) For any such new technology, we will publish a FEDERAL REGISTER notice based on information you submit and any other available information to announce that we have established new allowable minimum maintenance intervals. Any manufacturer objecting to our decision may ask for a hearing (see § 1036.820 ).(4)System components. The following provisions clarify which components are included in certain systems: (i) Catalyst system refers to the aftertreatment assembly used for gaseous emission control and generally includes catalyst substrates, substrate housings, exhaust gas temperature sensors, gas concentration sensors, and related control modules. SCR-based catalyst systems also include DEF level sensors, DEF quality sensors, and DEF temperature sensors.(ii) Particulate filtration system refers to the aftertreatment assembly used for exhaust PM filtration and generally includes filter substrates, substrate housings, pressure sensors, pressure lines and tubes, exhaust gas temperature sensors, fuel injectors for active regeneration, and related control modules.(b)Recommended additional maintenance. You may recommend any amount of critical emission-related maintenance that is additional to what we approve in paragraph (a) of this section, as long as you state clearly that the recommended additional maintenance steps are not necessary to keep the emission-related warranty valid. If operators do the maintenance specified in paragraph (a) of this section, but not the recommended additional maintenance, this does not allow you to disqualify those engines from in-use testing or deny a warranty claim. Do not take these maintenance steps during service accumulation on your emission-data engines.(c)Special maintenance. You may specify more frequent maintenance to address problems related to special situations, such as atypical engine operation. For example, you may specify more frequent maintenance if operators fuel the engine with an alternative fuel such as biodiesel. You must clearly state that this special maintenance is associated with the special situation you are addressing. We may disapprove your maintenance instructions if we determine that you have specified special maintenance steps to address engine operation that is not atypical, or that the maintenance is unlikely to occur in use. If we determine that certain maintenance items do not qualify as special maintenance under this paragraph (c), you may identify them as recommended additional maintenance under paragraph (b) of this section.(d)Noncritical emission-related maintenance. You may specify any amount of emission-related inspection or other maintenance that is not approved critical emission-related maintenance under paragraph (a) of this section, subject to the provisions of this paragraph (d). Noncritical emission-related maintenance generally includes maintenance on the components we specify in 40 CFR part 1068, appendix A, that is not covered in paragraph (a) of this section. You must state in the owners manual that these steps are not necessary to keep the emission-related warranty valid. If operators fail to do this maintenance, this does not allow you to disqualify those engines from in-use testing or deny a warranty claim. Do not take these inspection or other maintenance steps during service accumulation on your emission-data engines.(e)Maintenance that is not emission-related. You may schedule any amount of maintenance unrelated to emission controls that is needed for proper functioning of the engine. This might include adding engine oil; changing air, fuel, or oil filters; servicing engine-cooling systems; adjusting idle speed, governor, engine bolt torque, valve lash, injector lash, timing, or tension of air pump drive belts; and lubricating the heat control valve in the exhaust manifold. For maintenance that is not emission-related, you may perform the maintenance during service accumulation on your emission-data engines at the least frequent intervals that you recommend to the ultimate purchaser (but not the intervals recommended for special situations).(g)Payment for scheduled maintenance. Owners are responsible for properly maintaining their engines, which generally includes paying for scheduled maintenance. However, you may commit to paying for scheduled maintenance as described in paragraph (a)(1)(iv) of this section to demonstrate that the maintenance will occur. You may also schedule maintenance not otherwise allowed by paragraph (a)(2) of this section if you pay for it. You must pay for scheduled maintenance on any component during the useful life if it meets all the following conditions: (1) Each affected component was not in general use on similar engines before 1980.(2) The primary function of each affected component is to reduce emissions.(3) The cost of the maintenance is more than 2 percent of the price of the engine.(4) Failure to perform the maintenance would not cause clear problems that would significantly degrade the engine's performance.(h)Owners manual. Include the following maintenance-related information in the owners manual, consistent with the requirements of this section:(1) Clearly describe the scheduled maintenance steps, consistent with the provisions of this section, using nontechnical language as much as possible. Include a list of components for which you will cover scheduled replacement costs.(2) Identify all maintenance you consider necessary for the engine to be considered properly maintained for purposes of making valid warranty claims. Describe what documentation you consider appropriate for making these demonstrations. Note that you may identify failure to repair critical emission-related components as improper maintenance if the repairs are related to an observed defect. Your maintenance instructions under this section may not require components or service identified by brand, trade, or corporate name. Also, do not directly or indirectly require that the engine be serviced by your franchised dealers or any other service establishments with which you have a commercial relationship. However, you may disregard these limitations on your maintenance requirements if you do one of the following things:(i) Provide a component or service without charge under the purchase agreement.(ii) Get us to waive this prohibition in the public's interest by convincing us the engine will work properly only with the identified component or service.(3) Describe how the owner can access the OBD system to troubleshoot problems and find emission-related diagnostic information and codes stored in onboard monitoring systems as described in § 1036.110(b) and (c) . These instructions must at a minimum include identification of the OBD communication protocol used, location and type of OBD connector, brief description of what OBD is (including type of information stored, what a MIL is, and explanation that some MILs may self-extinguish), and a note that generic scan tools can provide engine maintenance information.(4) Describe the elements of the emission control system and provide an overview of how they function.(5) Include one or more diagrams of the engine and its emission-related components with the following information:(i) The flow path for intake air and exhaust gas.(ii) The flow path of evaporative and refueling emissions for spark-ignition engines, and DEF for compression-ignition engines, as applicable.(iii) The flow path of engine coolant if it is part of the emission control system described in the application for certification.(iv) The identity, location, and arrangement of relevant sensors, DEF heater and other DEF delivery components, and other critical emission-related components. Terminology to identify components must be consistent with codes you use for the OBD system.(6) Include one or more exploded-view drawings that allow the owner to identify the following components: EGR valve, EGR actuator, EGR cooler, all emission sensors (such as NOX sensors and soot sensors), temperature and pressure sensors (such as sensors related to EGR, DPF, DOC, and SCR and DEF), quality sensors, DPF filter, DOC, SCR catalyst, fuel (DPF-related) and DEF dosing units and components (e.g., pumps, metering units, filters, nozzles, valves, injectors), aftertreatment-related control modules, any other DEF delivery-related components (such as delivery lines and freeze-protection components), and separately replaceable aftertreatment-related wiring harnesses. Terminology to identify components must be consistent with codes you use for the OBD system. Include part numbers for sensors and filters related to SCR and DPF systems for the current model year or any earlier model year.(7) Include the following statement: "Technical service bulletins, emission-related recalls, and other information for your engine may be available at www.nhtsa.gov/recalls."(8) Include a troubleshooting guide to address the following warning signals related to SCR inducement: (i) The inducement derate schedule (including indication that inducements will begin prior to the DEF tank being completely empty).(ii) The meaning of any trouble lights that indicate specific problems (e.g., DEF level).(iii) A description of the three types of SCR-related derates (DEF level, DEF quality and tampering) and that further information on the inducement cause (e.g., trouble codes) is available using the OBD system.(9) Describe how to access OBD fault codes related to DPF-related derates.(10) Identify a website for the service information required in 40 CFR 86.010-38(j) .88 FR 4487, Jan. 24, 2023, as amended at 89 FR 29740, Apr. 22, 2024 88 FR 4487, 3/27/2023; As amended at 89 FR 29740, 6/21/2024