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Vehicle and Engine Certification

Confirmatory Testing for Engines and Vehicles


Confirmatory testing is for small nonroad spark-ignition (SI) and compression-ignition (CI) engines and is conducted at EPA's National Vehicle and Fuel Emissions Laboratory (NVFEL).

After receiving your test order from EPA, follow the steps below:

STEP 1: Identify the test engine.

After receiving your test order from EPA, identify the test engine you will send to EPA. If desired, test the engine at your facility prior to shipment.

Refer to the contact person on your test order for additional information.

STEP 2: Ship the test engine to EPA.

When requested by EPA, ship the engine to the location specified in your test order.

STEP 3: Confirm that you have access to Engines and Vehicles Compliance Information System (EV-CIS).

You must register with EPA to gain access to CDX's EV-CIS in order to submit initial test setup documents.
You must also set up an account with EPA to establish the "Upload Compliance Documents" role in EV-CIS.

STEP 4: Prepare the engine test setup documents.

Use the following materials to create your test setup documents:

STEP 5: Submit the engine test setup documents in EV-CIS.

Login to EV-CIS through the CDX portal: Central Data Exchange (CDX)

Submit the completed documents and upload any required supporting materials.

STEP 6: Confirm that your submission(s) from Step 5 were accepted by EV-CIS.

Within a few minutes of all submissions, the submitter will receive a notification in their CDX inbox indicating whether the submission was accepted or rejected.

To access your CDX inbox, click the "Inbox" link on the left navigation bar of the MyCDX homepage.

STEP 7: Determine whether to attend test setup; Review the test procedure.

EPA will notify the engine manufacturer approximately two weeks prior to the start of testing.

Manufacturers can attend the test setup, but are not permitted to observe the testing. Manufacturers who plan to attend test setup must inform the EPA certification representative or the contact listed in the test order.

For more information on the test procedure, see:

STEP 8: Review draft emissions test report and, if needed, make mechanical repairs.

Manufacturers will be notified upon completion of a valid confirmatory test and allowed to review the draft emissions test report on the first day of testing.

If the engine should fail the first emission test, the manufacturer will be permitted to make mechanical repairs to the engine on the second day. Any changes made to the engine must be documented and provided in writing or electronically to EPA certification personnel at the time of testing.

STEP 9: Receive official test results.

The official test results will be mailed to the manufacturer and will also be sent to the user's CDX inbox.

To access your CDX inbox, click the "Inbox" link on the left navigation bar.

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