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Tank integrity diagnosis, ORVR

Tank integrity diagnosis, ORVR


A check that no leakage occurs in the evaporative emission system can be carried out by means of tank integrity diagnosis. A leak is characterized in that a vacuum cannot be achieved or maintained in the system during the diagnostic process.

The diagnostics logic has been improved to provide surer diagnosis. It is now necessary for two tests with negative results to have been performed before a diagnostic trouble code is generated.

A new hose has been added for the purpose of checking that the fuel filler cap is in place and properly screwed down. This hose is connected between a T-union adjacent to the rollover valve and the upper part of the filler pipe. If the fuel filler cap is not in place, air will enter the system and no vacuum build-up can occur. A diagnostic trouble code is then generated.