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DEF Purging Cycle/Process

Entry DateJuly 28, 2013
Issue Number13-020-VEH
NameKerri Wirachowsky
AgencyOntario Ministry of Transportation
Address301 St. Paul Street, 3rd FloorSt. Catharines, ON, L2R 7R4CanadaMap It (opens in a new tab)
Phone905-704-2507
Fax(905) 704-2467
Email[email protected]
CommitteeVehicle Committee
StatusClosed
Summary of Issue

An inspector had sent in a request concerned as to whether inspectors may confuse the purging process for the DEF system on certain vehicles as an air leak. The DEF purge cycle is used to prevent the system from leaking. The purge cycle will occur immediately after the tractor is shut down. The vehicle’s air system is used to evacuate excess DEF from the DEF metering unit and nozzle supply hose. During the purge cycle, air can be heard leaking, which could be mistaken for a leak. It is normal for the air pressure gauge to drop between 9-12 psi during this cycle.

Justification or Need

Does this condition require an Inspection Bulletin to prevent inspectors from mistakenly writing this condition as a violation during an inspection.

Request for Action

If the committee deems it necessary, issue guidance to inspectors in relation this DPF purge.