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Occasional rough idle/flashing check engine light/corrected by battery disconnect?

35K views 10 replies 10 participants last post by  zabadad 
#1 ·
2013 fiat 500 pop manual.
This has happened about three times inthe last 3-4 months. Here is what happens.

Start the car, and the engine is idle violently rough. After so long the engine light will flash and the car will go into limp mode. Kill the engine, crank again, the same thing. If you disconnect the battery for about 20 minutes and reconnect it, it's like nothing ever happened. Engine runs smooth as butter with no lingering issues. Seems to work fine for about a month. Then one random morning it happens again. Violent engine idle (almost like a cylinder isn't hitting), check engine light. Disconnect battery and wait ... reconnect, no issues. 30-40 more days of solid driving. It happened again yesterday morning with the same resolution.

Has this happened to anyone else? I am fearful to drive it into Fiat when it's working fine, only to have them tell me they don't see any problems.

Should I just wait until it happens again and have it towed into Fiat for inspection while the engine light is still on? I feel like if there was a legitimate engine problem that a computer reset (or whatever the battery disconnect is doing) wouldn't have much effect.
 
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#2 ·
are you in a cold climate? pretty common for these cars to get the flashing CEL for misfire on cold start.

I'd point to plugs or coils otherwise.
 
#3 ·
Not too cold, no. After your suggestion of coils or plugs, I looked up symptoms and that sounds exactly like what I experienced those few times. My question is, though. If there really is a faulty coil or plug, why would disconnecting the battery temporarily resolve the issue. Killing and restarting the engine without doing that never works.
 
#4 ·
Happen once. Hadn't driven the car for a while. Started the car. Ran really rough. The engine sounded really sick. Put in reverse, it died. Started the car again, it ran just fine. Suspect the battery was low on charge. Took the car for a drive. Never happen again.
 
#5 ·
These cars *need* new plugs at the specified intervals. Need. A worn spark plug has a wider gap than factory so the coil has to work harder and can wear out prematurely. I had to replace a coil on cyl 1 at 60K miles.

Resetting the ECU might clear the code that an overworked coil would throw. Pull your plugs and check the gap and go from there.
 
#6 ·
Hi Bad Wolf,

If you decide to visit your local studio for further diagnosis I'd be happy to follow up with them for you if needed. Just PM our page with your VIN and let me know!

Andrea
Fiat Social Care Specialist
 
#7 ·
@Bad Wolf What happened with the car!?? I'm having very similar issues with my 500 Twinair. It's had the spark plugs replaced and it's in the garage again because it does the same thing as before, if not worse. Very rough idle when I start the car. Engine light comes on about 30 seconds to a minute after starting. I have to kill the motor and restart the car about 5 times before I can actually drive the car. Before the car used to drive and the engine light came on a few minutes into driving; it was scary because I couldn't switch gears once the light came on! I'd love to know what happened with your car. I'm waiting on a call back from my mechanic today. Thanks!
 
#10 ·
My 2013 is doing the same - and when I check the codes - basically every pcm and ecm code it has. I was getting evap leak code prior to this problem. And the lights and limp mode seem to happen at the end of the evap cycle monitoring. So about to replace purge valve which I suspect is stuck open or closed and throwing the computer into a fit. Gremlins. Will post result.
 
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