[Mech]

I'm at 23k miles and the CEL just came on. The warning system gave an "Engine system malfunction" message which sounds pretty bad. I went to autozone to check the code and got a P0456 evap system (very small leak).

A little research suggests a fuel cap is the most likely cause. In my case, I hadn't filled up in a few days when the code came on. I checked and closed the cap several times and the CEL won't go away.

Any thoughts?

Is this kind of thing covered under warranty? I've never taken my car to the deal for work before.

 

[oscargamer]

If your car is under warranty, then yes, take it back to the dealer and get them to sort it.

Don't try and fix it yourself, they might say you have worsened the problem.

 

[M3Nitro]

To rule out an anomaly causing the DTC you should have the DTC cleared to see if the DTC returns. Also while they are checking things at the diagnostic connector , have a look into the monitors to see is any are in fault!

Doing this procedure will NOT worsen any condition nor does it violate anything in the warranty.

Should you take it to a dealer they will be doing the same thing.

 

[oscargamer]

Doing this procedure will NOT worsen any condition nor does it violate anything in the warranty.

Wasting time and money though (if they charge)

Stealership required to fix

 

[arathol]

Stealership required to fix

Yes, especially if its under warranty.

 

[M3Nitro]

. I went to autozone .

:laugh2: Autozone offers the service I recomended for FREE.
It is easier then going to a dealership if it ends up only being an anomaly that generated the DTC! :wink2:

 

[M3Nitro]

BTW..... I get at least a vehicle every other week that is still under warranty that comes into the shop with a DTC. Most of the time it is as I said...easy peasy to note the code, clear it(re-set monitors sometimes) and tell the customer NO CHARGE call me in the morning should the DTC (or in the next few days) returns!

 

[Mech]

If it was just an anomaly, the code would clear on it's own after some time, right? It's been 2 days and about 400 miles and the code hasn't budged.

 

[zero_gravity]

If it was just an anomaly, the code would clear on it's own after some time, right? It's been 2 days and about 400 miles and the code hasn't budged.

Some codes must be cleared by a code scanner before they will go away.

But honestly, as other users have said you're under warranty. Use what you paid for. You did good checking the gas cap, time to move on. Your car should have a secondary light on the dash for a loose gas cap, I know mine does.

 

[M3Nitro]

This is why I suggested to look at the "monitors" and other things. If any monitors are in fault it could take several cycles before they are "set".
There is also a complete trouble shooting Diagnostic tree to follow with the DTC you entered on this thread. The gas cap is a single item.

Sorry but when people question my advise and recommendation without first attempting to try it I feel that my usefulness is done.
Good luck with your diagnostic problem!

 

[M3Nitro]

A worthwhile investment.

UltraGauge OBDII Scan tool & Information Center

Post #9
http://mazda3revolution.com/forums/...interior/218898-nitro-s-mazda3-avocation.html

 

[2017mazda3]

This is why I suggested to look at the "monitors" and other things. If any monitors are in fault it could take several cycles before they are "set".
There is also a complete trouble shooting Diagnostic tree to follow with the DTC you entered on this thread. The gas cap is a single item.

Sorry but when people question my advise and recommendation without first attempting to try it I feel that my usefulness is done.
Good luck with your diagnostic problem!

On my previous Mazda there was one very specific OBD (maybe evap?) which required the car to be driven at 50 to 60 miles per hour for 7-10 miles within 3-4 minutes from a completely cold 8 hour start...fortunately I lived close to a freeway and that was fairly easy achieve and clear...except for the few honks for driving too slow, but you have to know it as most people don't drive the exact way to clear out every OBD in short order. Clearly, other OBD's can take a week or two to clear out and few hundred miles to clear based on time and specific driving habits required...I always warn people not to clear/reset/disconnect battery etc. too soon prior to emissions testing if they don't have a scanner to confirm beforehand.

In one instance with my Acura, had a loose gas cap and did set off the CEL, but the light turned off within an hour or so max before I even got home to check.