Check Engine Light Due to Improperly Manufactured Threads on Fuel Filler Pipe on Mazda Miata MX-5

Some models may have a problem where the Check Engine light illuminates indicating an improperly tightened fuel cap. Due to improperly manufactured threads on the fuel filler pipe, the filler pipe may need to be replaced.

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Average mileage: 38,687 (4,000–145,000)
10 model years affected: 1994, 1999, 2006, 2007, more2008, 2009, 2010, 2012, 2013, 2014
31 people reported this problem
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Viewing 1 - 18 of 18 problem details
2006 Mazda Miata MX-5 29,605 mi,
check engine light comes on. Dealer Service shows problems with fuel filler pipe but this vin# not included in recall. Why?
2012 Mazda Miata MX-5 47,000 mi,
Check engine light came on this morning. Opened then tightly closed fuel filler cap, but had no effect.
2007 Mazda Miata MX-5 38,000 mi,
Starting when I bought this car used with 37000 miles on it I get a check engine light the code set is a loose gas cap and has now occurred 3 times in the last 9000 miles. I know that the cap has been reinstalled properly after refueling and I have to bring the car to my mechanic to reset the engine light, the cap is loose when the light comes on.
2014 Mazda Miata MX-5 4,000 mi,
When I fill up I have to reseat the gas cap and the light still stays on
2012 Mazda Miata MX-5 16,500 mi,
CEL comes on Gas cap comes loose
2013 Mazda Miata MX-5 26,000 mi,
Check engine light comes on. The system code says a loose gas cap. the cap even gets so loose that it will come off in your hand, even if you tighten it. I think it must be the fuel filler pipe, the threads must be bad. Next step is to talk to the dealer.
2010 Mazda Miata MX-5 8,444 mi,
Taken the car in to the dealership 3xs. They continue to maintain that the light is on because I am not "tightening the gas cap enough"! I KNOW how to tighten a gas cap!! Today I was humiliated while the service consultant explained that "if" I am telling them the truth, they will do me a "favor" by replacing the gas cap, because it is clearly the owner's mistake and not theirs! Grrrrrr
2008 Mazda Miata MX-5 24,529 mi,
I cleaned the rough edges from the cap, put silicone lube ( used for pool o rings) disconnected the + battery terminal, turned on the key while depressing the brake pedal. After about 2 minutes I reconnected the battery and the light functioned properly.
2008 Mazda Miata MX-5 70,000 mi,
Check engine light illuminates often. Code says evap system leak. I just clear the code, retighten the cap and keep going. It happens about once a month.
2007 Mazda Miata MX-5 49,000 mi,
check engine light comes on after fill up and goes off after about one quarter gone
2008 Mazda Miata MX-5 73,000 mi,
Check engine light has been on now for several weeks. I went to a parts store and ordered a new gas cap. Put the new gas cap on and CEL is still on. Next step is to go purchase a gas cap from the MAZDA dealership.
2009 Mazda Miata MX-5 30,000 mi,
Happened twice, dealer replaced fuel cap, then a sensor in the trunk.
2006 Mazda Miata MX-5 9,550 mi,
got code p0442 and replaced fuel cap with new redesigned mazda one. light stayed off for 100 mile and came on again. cap was loose. dealer will not fix.
2012 Mazda Miata MX-5 16,000 mi,
Check engine light came on. The code read by the service center pointed to the fuel filler cap. It was replaced and the problem went away.
2010 Mazda Miata MX-5 21,941 mi,
engine light comes on and stays on, the fuel filler cap is loose, I tighten it and in a few days it comes loose again all on its own.
2006 Mazda Miata MX-5 61,500 mi,
Check engine light on
2006 Mazda Miata MX-5 24,030 mi,
Repeated check engine lights after fueling vehicle and tighening gas cap.
1999 Mazda Miata MX-5 145,000 mi,
I have not fixed the problem, but every time I fill up the gas tank, the check engine light comes on. Once the fuel level drops below 1/4 tank it goes away.