Leak Test Failed?

[Rearanger]

Testing a new (cheap) OBDII code reader. Got this reader as a fast way to get codes and see some generic parameters. I have a PC based scanner, but it's bulky and cumbersome to hook up and if I want to do a quick check on a vehicle all I need is a simple reader.

Anyway, going through the data (no DTCs) it shows "Evap System Mode $8 Leak Test Failed".

Can someone explain this and if there's a leak why no code?

Thanks

 

[Dirtman]

It can't run the test unless specific criteria are met. It didn't fail because its actually leaking, the test failed because it didn't meet to criteria to perform the test.

 

[Rearanger]

It can't run the test unless specific criteria are met. It didn't fail because its actually leaking, the test failed because it didn't meet to criteria to perform the test.

A little more study after reading your post tells me the criteria may be hard to meet.

Depending on where and how the vehicle is typically used, it's common that the EVAP monitor will not run to completion for months at a time, and it's even possible that the test will never be completed. If the monitor does run and detect a small leak, it must do so twice before it will set a hard fault code and turn on the malfunction indicator lamp (MIL).

Would the above statement be true?

 

[Dirtman]

Yes the criteria is a bit complex. Ambient temp needs to be a certain range, fuel level needs to be in a certain range, engine load and rpm need to meet certain specs. Engine also has to run through a certain number of heat cycles. Basically it'll run the test when it feels like it and theres no reason to bother worrying about it. If I recall last time I cleared the ECM it took about a week for all the tests to re-run.

 

[Rearanger]

Thanks for the follow up.

 

[Dirtman]

Just drive normal, keep the tank full-ish, and recheck it in a week.