EVAP Purge Test Diagnosis

The evaporative purge test is performed during the IM240 transient (drive cycle) test. A flow transducer is placed in series with the purge line between the canister and engine. In order to pass, the system must purge at least 1 liter of flow by the end of the IM240 drive cycle. Toyota vehicles with properly operating EVAP systems normally purge 25 liters or more by the completion of drive cycle.

If the EVAP system fails the purge test, a problem exists with the purge port, the purge hose to the canister, or the charcoal canister itself. Since 1 liter of flow is such a nominal amount, the test really only verifies whether the system is purging or not. There are checks that you can make to confirm vacuum to the canister or the effects of purge flow on the air/fuel mixture; however, the only real way of measure actual flow volume is to use a flow transducer, similar to the one used in the actual purge test.

EVAP Purge Test (Using Special Test Equipment)

Aftermarket test equipment may also be used to perform an EVAP purge test in a similar manner to IM240.

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Responses

  • marmaduke
    What part of drive cycle does ecu perform evap test 2001 toyota avalon?
    2 years ago

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