A little over a year ago the coil pack failed. Engine was underpowered because it only running on 3 cylinders. I took it to a local garage who replaced it and it's been running fine.

Last week the engine warning light comes on, I had it booked in to the Ford dealership for a service anyway so asked them to look at it. They told me it was the coil pack. I thought this was odd as it was only done a year ago and the engine was running fine but they insisted that's what it was so I had them change it.

Today I was driving my car for the first time since they delivered it back and the light came on again after about 1 mile.

A series of unrelated issues while they had my car left me questioning their competency. So my question is, could they have gotten an old fault from the computer from when it actually failed last year if the other garage didn't reset it?

They are picking up the car again in the morning but I'm not paying for a replacement coil pack if the old one didn't need changing.


1 Answer 1


If the computer hasn't been cleared and it has had power the whole time (no battery failures), it might be an old engine code ... but considering what you got done, I'm doubting it. If I got a car with a code, the first thing I do is clear them to see if they come back. If the code comes back, then I investigate the actual code which pops. Once I get things figured out, I'll clear the codes again to ensure it doesn't come back. This ensures I'm not chasing an old code. A competent shop would do much the same, I'd think.

  • I did have a battery failure a few months back so it lost power, I had to put the radio code in. Didn't know if fault codes would persist across that.
    – A Jackson
    May 9, 2017 at 21:53
  • @AJackson - No, at least on most vehicles they won't. If the battery is dead for anything more than 30 minutes, all the stored information will be wiped out. May 9, 2017 at 22:09
  • @AJackson a code won't persist over a years time unless its actively failing the monitor most codes are self cleared over a number of good drive cycles and i'd imagine that the shop that replaced the coil the first time reset the mil with a scan tool.
    – Ben
    May 10, 2017 at 13:04

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