Check engine light on p0356

Made a repair on a coil pack including spark plug, truck is running back to normal but light has not gone off as of yet & it has been driven about 120miles...anyone with experience having to drive more miles than that for the light to go off?

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I believe you have to clear the code first with an OBD reader. I had to with mine.

Yes. Not to contradict Jeff, but if the 'systems' see it is performing correctly, I have read/heard the CEL/MIL should clear itself...

Yeah, mine required a Hard Clear from a mechanic to stay gone. Most of the OBD readers at Auto Parts stores only do a soft clear, from what I was told. Took mine to a mechanic friend at a shop, and he told me that and cleared the code for me for free and it has been gone for about 2000 miles.

CountrySplatt said:

Yeah, mine required a Hard Clear from a mechanic to stay gone. Most of the OBD readers at Auto Parts stores only do a soft clear, from what I was told. Took mine to a mechanic friend at a shop, and he told me that and cleared the code for me for free and it has been gone for about 2000 miles.

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IMO even a cheap code reader ($20?) is an essential tool for working on these vehicles. I've done loads of repairs based on faults read and cleared by a basic model, mainly misfires and vacuum leaks. I've never heard of hard/soft clears but i've never had a problem clearing any of them with el cheapo unit.

I did some research on this. It requires 40 "drive cycles" to auto clear. A drive cycle is: start the car, drive it for a while, stop car, turn off car.

In some cases, if you disconnect a battery lead for 10 minutes and reconnect it, the computer will reboot when re started. If it does not clear the code, it will not screw up the car.

Buy a code reader. I have seen them on sale for $40 at Harbor freight. Mine is 15 years old and still works.

Note: if you clear the code and it comes back, the problem may still be there. When mine ate a coil. I changed all the coils and plugs. I used NAPA gold coils at $35 each and 50K miles later it still purrs smoother than my cat.

CountrySplatt said:

Yeah, mine required a Hard Clear from a mechanic to stay gone. Most of the OBD readers at Auto Parts stores only do a soft clear, from what I was told. Took mine to a mechanic friend at a shop, and he told me that and cleared the code for me for free and it has been gone for about 2000 miles.

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Get a $12 panlong elm327 from amazon. Reads and clears codes and shows a gazillion graphable stats with your phone, tablet, or aftermarket android headunit.

Lasts for years.

And don't listen to parts store bs.

P0356 is an open circuit malfunction. That means bad connection or bad wiring harness. On my Expedition, I had a different code for the coil. I think it was P0303. When I installed the new one and started the engine, the flashing CEL was out.

I've always disconnected the battery and let it sit for a while before reconnecting.

Wegner44 said:

I've always disconnected the battery and let it sit for a while before reconnecting.

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If the 'misfire' is gone the flashing 'service engine' light will not flash. There is no code to clear.