I think it might have been as simple as the fuel cap not being tightened enough for the fuel system to pressurize. I've always been told to tighten it till it clicks 3-4 times. But fuel caps are cheap enough that if you tighten it well and the CEL still comes on, then it's probably time to replace it.
Gas cap / Fuel Filler Cap Issue
- Thread starter LexustoMazda
- Start date
I copied my original answer to make it easier for viewers to follow my progress: I now have about 22,800 miles, and this problem persisted. In fact, it caught me on a trip to Fort Worth and back resulting in driving about 700 miles with the fuel cap light on non-stop. Very unsettling in a vehicle that had never even seen the inside of a shop! Along the way I bought and installed an accessory fuel cap from O'Rilley which had no effect (even after twice the driving cycle requirement). So, today I took it in to my selling dealer who happened to have the time to hop on it immediately. (Legend Mazda - who, by the way, has replaced all their service writers including the one mentioned above)
Their little diagnostic computer, which plugs in under the dash on the drivers side, said "gas cap evap system leak." So, somewhere up in that cap is an evaporative "system" that can get out of whack. They don't stock the cap, but for some reason they had one on the shelf (divine intervention) they reset the computer codes, and I was in and out of the place in about an hour.
They did tell me that Mazda gas caps were American made, and replacements from other countries were troublesome. They gave me the plastic package the new one came in and it said USA right on the front!
hopefully all this will save someone else some grief.
Kind of off thread, while I was there, I had a chance to look at the new Sky-activ CX5. Wow! That thing is absolutely great, and I was amazed st the interior room. That thing is going to be a strong contender.
One fill up after the dealer replaced my fuel cap and reset the codes, the "check Engine" lamp came to life. Previously as you remember from this thread it was the fuel cap light. I took the vehicle to my dealer here in San Antonio, they reset the codes, and told me the only code was fuel cap improperly installed. Now I've driven this CX for about two and a half years, and only been fighting this problem for about 6 months. Anyway they reset the codes, again, and today after having used half a tank of fuel the check engine light is on again. Now it seems (and it sure may be my imagination) like the Mazda is a tad sluggish. I'm looking for help here from someone who may have fought through this same situation. I'm also looking for a consensus on the number of clicks the average member hears when he or she puts the cap on. Normally I get 6-8 clicks, but I have tried everything from 1 click to about three complete revolutions. I really believe I have a sensor problem, but can't prove it, and the codes the dealer is getting are not supporting that theory.
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There is no code for "gas cap." The cap is part of the evaporative system(EVAP). It should be a P0440 or P0442 code. The gas cap is the first thing they check and it is usually the culprit. If that doesn't clear the CEL, then they need to check a little deeper. It could be a small leak in the evaporative hose since it doesn't take much of an air leak to set off a CEL.
Take it back and tell them they need to look a little a little harder. Get a copy of diagnostic report and a copy of the diagnostic manual for the code. There is a list of potential causes. Have them look at everything on the list including another gas cap.
Take it back and tell them they need to look a little a little harder. Get a copy of diagnostic report and a copy of the diagnostic manual for the code. There is a list of potential causes. Have them look at everything on the list including another gas cap.
Well, Hallelujah! Finally something other than "improper fuel cap installation." After reading JK240sx's post, I rolled up my sleeves and prepared for whatever was coming. This was the 5th time with this problem, and enough is enough. Bottom line was when they "looked a little harder" they came up with a new code, indicating the purge valve (which as explained to me is a pump) was faulty. Once the repairs were completed, I knew that the reduced performance that I thought I noticed was in fact true. As a layman, my best guess is that faulty data input to the fuel management electronics causes a change in what those systems believe the vehicle needs. Anyway I could detect an immediate change.
However, I must add that there was a PCM upgrade flash available, and they did that also, so who knows what changed what. In my 46 years of motorcycling, one of the very first things I learned was to change one thing at a time!
Bottom line is the vehicle seems fine - and I fell in love with the CX5 - but we run our vehicles for 10 years - and I've had this one 2.
You should know that this one is a 2010, and if you have a 2010, you might check on the firmware upgrade and see if it applies to your VIN next time you have it in.
However, I must add that there was a PCM upgrade flash available, and they did that also, so who knows what changed what. In my 46 years of motorcycling, one of the very first things I learned was to change one thing at a time!
Bottom line is the vehicle seems fine - and I fell in love with the CX5 - but we run our vehicles for 10 years - and I've had this one 2.
You should know that this one is a 2010, and if you have a 2010, you might check on the firmware upgrade and see if it applies to your VIN next time you have it in.
Glad they finally nailed it down. whenever I take a vehicle in for a CEL, upfront I state I want to see the code readout and the manual for the diagnostics. Right off the bat they know I am not going to take for granted what they tell me and I'm not a guppy. There are a few good techs out there but too many lazy ones.
Yeah, I learned from you on this one. Thank you.
Update: I drove this tank of fuel to the "fumes" level with the light on. Filled it completely, replaced the cap with 6 clicks, and within about 6-8 drive cycles the light went out, and has not returned. I'm on my second tank since it went out. This seems suspicious that perhaps this one was operator error.
If anyone has been following this comedy, the saga of the gas cap light interspersed with the check engine light as continued on and off since my last post. I took the vehicle in last week, they reset the codes, and installed a second new gas cap. My selling dealer's shop wanted to do a leak down test of some sort, which required nitrogen, but they didn't have either the required machine, or the nitro - I never really got to the bottom of that. The feeling I came away with was the management of the dealership didn't really want to lay out the bucks for whatever they needed. The good news is first, over the weekend the lights have not come back on, and secondly I went to the EPA website and found a complete list of all the components covered under the emissions equipment performance warranty. (FYI, there are two different warranties for emission equipment). Everything in the evaporative system is covered by law for 8 years, or 80,000 miles. At this time I have about 28,000, but I reach the 36 month warranty expiration in March of 2013. It is comforting to know that they will continue to see me, if I have continued problems, for some time to come. I am fully aware that there are two other Mazda dealers in San Antonio, however, I feel like my selling dealer (which is a full service Mazda/Kia dealer) should be able to diagnose, and repair any system on the vehicle. They should also have the willingness to have everything on hand to do so, and have the trained personnel in house to understand what the computer is telling them. The more I am involved with this difficulty, the more I have come to realize that this type of situation is one of diagnosing the complete emission system, and simply swapping parts as the codes direct.
I have had this vehicle to this dealer 9 times for this one difficulty. If I didn't just love this crossover, we'd have been talking about a lemon as regards the emissions. The Feds would just love that!
The good news is, as I said, they may have fixed it this time (however, I don't know what the calculations might be regarding two bad gas caps in a row). Secondarily, additional good news is that I'm retired - so . . .
I have had this vehicle to this dealer 9 times for this one difficulty. If I didn't just love this crossover, we'd have been talking about a lemon as regards the emissions. The Feds would just love that!
The good news is, as I said, they may have fixed it this time (however, I don't know what the calculations might be regarding two bad gas caps in a row). Secondarily, additional good news is that I'm retired - so . . .
Yeah, you're right. Well, the bottom line is that after 9 months, and 11 trips to my selling dealer, I still have a nice bright fuel cap light on the dash. Good thing they put a long life bulb in that. Yesterday, I called my service writer at Legend Mazda here in San Antonio, and the bottom line is he told me they had an adapter ordered to do the nitrogen test, and he didn't know when they'd get it. Get this, he recommended I take the car to another Mazda dealer to see if they might have the part. That tells me I am the squeaky wheel, and am beginning to get some grease. I will say this really reflects poorly on Mazda to have a franchised dealer who cannot perform normal maintenance and repairs. I did try to locate a phone number on line for Mazda's service people, but found nothing. Man I hate to get an attorney involved - but - in Texas, if they cannot fix the vehicle, they get to refund the purchase price. Sadly, if they cannot repair it, I am an air polluter, who may not be able pt pass the next state inspection! Pretty dumb for a dealership to hang the company out like this. If anyone has a number for Mazda's service people for Texas - I sure would appreciate a PM.
