§571.138. Standard No. 138; Tire pressure monitoring systems. — Inbound Citations

(iii) References to “spark-ignition standards” in this part relate only to the spark-ignition engines identified in paragraph (2)(i) of this definition. References to “compression-ignition standards” in this part relate to compression-ignition engines, to spark-ignition engines optionally certified to standards that apply to compression-ignition engines, and to all engines identified under paragraph (2)(ii) of this definition as heavy heavy-duty engines.

Rechargeable Energy Storage System (RESS) means the component(s) of a hybrid engine or vehicle that store recovered energy for later use, such as the battery system in an electric hybrid vehicle.

Refuse hauler has the meaning given in 40 CFR 1037.801.

Regional has the meaning relating to the Regional duty cycle as specified in 40 CFR 1037.510.

Regulatory category means each of the four types of heavy-duty vehicles defined in 49 CFR 523.6 and the heavy-duty engines used in these heavy-duty vehicles.

Regulatory subcategory means the sub-groups in each regulatory category to which mandatory fuel consumption standards and requirements apply as specified in 40 CFR 1036.230 and 1037.230 and are defined as follows:

(C) Tire pressure monitoring systems must use low pressure warning and malfunction telltales in clear view of the driver as specified in S4.3 and S4.4 of 49 CFR 571.138.