This report reviews the performance of the Johnson Matthey PCRT2(Trade Name) 1000, v.2 system, comprising a flow-through partial filter and a diesel oxidation catalyst (DOC) submitted for testing by Johnson Matthey Plc. Environmental technology verification (ETV) testing of this technology was conducted during a series of tests in August 2008 by Southwest Research Institute (SwRI), under contract with the Air Pollution Control Technology Verification Center (APCT Center). The APCT Center is operated by RTI International (RTI)* in partnership with the U.S. Environmental Protection Agencys (EPA) ETV program. The objective of the APCT Center and the ETV program is to verify, with high-quality data, the performance of air pollution control technologies, including those designed to control air emissions from diesel engines. With the assistance of a technical panel of experts assembled for the purpose, RTI has established the APCT Center program area specifically to evaluate the performance of diesel exhaust catalysts, particulate filters, and engine modification control technologies for mobile diesel engines. Based on the activities of this technical panel, the Generic Verification Protocol for Diesel Exhaust Catalysts, Particulate Filters, and Engine Modification Control Technologies for Highway and Nonroad Use Diesel Engines was developed. This protocol was chosen as the best guide to verify the immediate performance effects of the PCRT2(Trade Name) 1000, v.2 system. To determine these effects, emissions results from a heavy-duty highway diesel engine were compared to emissions results obtained operating the same engine with the same fuel, but with the PCRT2(Trade Name) 1000, v.2 technology installed. The specific test/quality assurance (QA) plan addendum for the ETV test of the technology submitted by Johnson Matthey was developed and approved in April 2008. The goal of the test was to measure the emissions control performance of the PCRT2(Trade Name) 1000, v.2 system and its emissions reduction relative to an uncontrolled engine.