40 CFR §1042.320

1. (a)If you have a production-line engine with final deteriorated test results exceeding one or more emission standards (see § 1042.315(a)), the certificate of conformity is automatically suspended for that failing engine. You must take the following actions before your certificate of conformity can cover that engine:
   1. (1)Correct the problem and retest the engine to show it complies with all emission standards.
   2. (2)Include the test results and describe the remedy for each engine in the written report required under § 1042.345.
2. (b)You may request to amend the application for certification to raise the FEL of the entire engine family at this point (see § 1042.225).
3. (c)Use test data from a failing engine for the compliance demonstration under § 1042.315 as follows:
   1. (1)Use the original, failing test results as described in § 1042.315, whether or not you modify the engine or destroy it. However, for catalyst-equipped engines, you may ask us to allow you to exclude an initial failed test if all the following are true:
      1. (i)The catalyst was in a green condition when tested initially.
      2. (ii)The engine met all emission standards when retested after degreening the catalyst.
      3. (iii)No additional emission-related maintenance or repair was performed between the initial failed test and the subsequent passing test.
   2. (2)Do not use test results from a modified engine as final test results under § 1042.315, unless you change your production process for all engines to match the adjustments you made to the failing engine. If you change production processes and use the test results from a modified engine, count the modified engine as the next engine in the sequence, rather than averaging the results with the testing that occurred before modifying the engine.