---
kind: "section"
citation: "40 C.F.R. § 86.1915"
title: "40"
number: "86.1915"
heading: "What are the requirements for Phase 1 and Phase 2 testing?"
url: "https://uscodex.org/cfr/40/86.1915"
---

# §86.1915. What are the requirements for Phase 1 and Phase 2 testing?


For all selected engine families, you must do the following:

- (a) To determine the number of engines you must test from each selected engine family under Phase 1 testing, use the following criteria:
  - (1) Start by measuring emissions from five engines using the procedures described in [§ 86.1375](/cfr/40/86.1375.md). If all five engines comply fully with the vehicle-pass criteria in [§ 86.1912](/cfr/40/86.1912.md) for all pollutants, you may stop testing. This completes your testing requirements under this subpart for the applicable calendar year for that engine family.
  - (2) If one of the engines tested under [paragraph (a)(1)](#a-1) of this section fails to comply fully with the vehicle-pass criteria in [§ 86.1912](/cfr/40/86.1912.md) for one or more pollutants, test one more engine. If this additional engine complies fully with the vehicle-pass criteria in [§ 86.1912](/cfr/40/86.1912.md) for all pollutants, you may stop testing. This completes your testing requirements under this subpart for the applicable calendar year for that engine family.
  - (3) If your testing results under paragraphs [(a)(1)](#a-1) and [(2)](#a-2) of this section do not satisfy the criteria for completing your testing requirements under those paragraphs for all pollutants, test four additional engines so you have tested a total of ten engines.
  - (4) An engine that fails to fully comply with the vehicle-pass criteria in [§ 86.1912](/cfr/40/86.1912.md) for any pollutant does not comply with the vehicle-pass criteria in [§ 86.1912](/cfr/40/86.1912.md) for the purposes of determining the number of engines to test from each selected engine family under this paragraph.
- (b) For situations where a total of ten engines must be tested under [paragraph (a)(3)](#a-3) of this section, the results of Phase 1 testing lead to the following outcomes:
  - (1) If at least eight of the ten engines comply fully with the vehicle-pass criteria in [§ 86.1912](/cfr/40/86.1912.md) for all pollutants, you may stop testing. This completes your testing requirements under this subpart for the applicable calendar year for that engine family.
  - (2) If six or seven vehicles from the Phase 1 sample of test vehicles comply fully with the vehicle-pass criteria in [§ 86.1912](/cfr/40/86.1912.md) for all pollutants, then you must engage in follow-up discussions with us to determine whether any further testing (including Phase 2 testing), data submissions, or other actions may be warranted.
  - (3) If fewer than six of the ten engines tested under [paragraph (a)](#a) of this section comply fully with the vehicle-pass criteria in [§ 86.1912](/cfr/40/86.1912.md) for all pollutants, we may require you to initiate Phase 2 testing, as described in [paragraph (c)](#c) of this section.
  - (4) You may under any circumstances elect to conduct Phase 2 testing following the completion of Phase 1 testing. All the provisions of [paragraph (c)](#c) of this section apply to this Phase 2 testing.
- (c) If you perform Phase 2 testing for any reason, test your engines as follows:
  - (1) You must test ten additional engines using the test procedures described in [§ 86.1375](/cfr/40/86.1375.md), unless we require you to test fewer vehicles.
  - (2) We may give you any of the following additional directions in selecting and testing engines:
    - (i) We may require you to select a certain subset of your engine family. This may include, for example, engines within a specific power range, engines used in particular applications, or engines installed in vehicles from a particular manufacturer.
    - (ii) We may direct you to test engines in a way that simulates the type of driving and ambient conditions associated with high emissions experienced during Phase 1 testing.
    - (iii) We may direct you to test engines in a specific state or any number of contiguous states.
    - (iv) We may direct you to select engines from the same sources used for previous testing, or from different sources.
    - (v) We may require that you complete your testing and reporting under Phase 2 within a certain period. This period may not be shorter than three months and must allow a reasonable amount of time to identify and test enough vehicles. We would generally expect this testing to be completed within the overall time period specified in [§ 86.1905(d)](/cfr/40/86.1905.md?p=d).

## Notes

### Source

Source: 70 FR 34619, June 14, 2005, unless otherwise noted.

### Authority

Authority: 42 U.S.C. 7401-7671q.