Powertrain warning on manual 2010 Fiesta

[JenHarris]

Hi,

I have a 60 plate Fiesta Zetec which I purchased second hand almost 8 years ago. It's served me well and still has almost all its original parts, but I've been having some problems with a powertrain warning light recently. 

3 weeks ago I left to go to work and my car wouldn't start, so a neighbour kindly helped me with a jump start. My battery must have been really flat because it took a while to get it going, but we did. It was fine for my hour long commute but when I headed home I had a powertrain warning light come on with "Engine malfunction service now" on the console. I pulled over and turned it off and back on again, it took 10 minutes or so for the light to come back but it then stayed til I got home.

The next day I took it to the garage, the light was gone. I tend to use a local branch of a garage chain because the staff in that particular branch have always been super helpful. They were baffled that I had this light on a manual car but connected it up and found it was displaying a brake light switch and reverse gear sensor fault. Once they'd cleared those they verified that the brake lights were working properly and reverse gear was working so told me to bring it back if it happened again.

I don't drive much these days so it wasn't until my next long run 2 weeks later that I saw the light again. Again it went off eventually and didn't come back. I returned to the garage where it again showed a fault with a brake light switch. They replaced both brake light switches and cleared the codes hoping this would be it. Unfortunately not- the error came back last night.

The car drives absolutely fine when this error happens, up to mid 70s with no reduction in power, no strange noises, nothing. The only thing I've noticed is the green "shift up" light on the dash doesn't work when it's displaying the fault - this is in no way an issue to me as I tend to ignore it anyway. It hasn't happened enough times to be sure this is a pattern but every occurrence so far has happened in the evening, at least 15 minutes into a journey where the previous journey was over an hour in duration. That's all I've got and I have no idea where to go next with this!

Has anyone seen anything like this before? I'm not sure if it might be time to take it directly to Ford. My plan is to sell it in the next 2-4 years to buy a bigger family car so I am considering cutting my losses rather than sinking a small fortune into it only to sell it soon anyway. 

Thanks in advance 

[Neb_engineer]

whats the health of your battery, usually if the battery is failing, the cars systems tend to go a bit odd until the battery is replaced as the battery voltage can be unstable

[JenHarris]

2 hours ago, Neb_engineer said:

whats the health of your battery, usually if the battery is failing, the cars systems tend to go a bit odd until the battery is replaced as the battery voltage can be unstable

Ooh interesting, the battery is a bit tired I think as it's around 5 years old and was one of the cheapest I could get as I was skint at the time! I did test it after needing a jump start the other week and it seemed a little bit low, if I remember correctly I think it read 12.32v with the engine off and 14.6 when running. I've been planning to replace it but held off as it's been starting fine since that one instance of going flat and I'm concerned this car is going to become a money pit. I asked about the battery when I picked it up from the garage last week and was dismissed but it is a bit suspicious that this fault first appeared the same day I needed a jump start. I'm happy to invest in a new battery if that might be the culprit 

[Neb_engineer]

how long between you driving the car and you testing the battery?

[JenHarris]

10 hours ago, Neb_engineer said:

how long between you driving the car and you testing the battery?

3 days I think

[Neb_engineer]

11 hours ago, JenHarris said:

3 days I think

i don't think the voltage should have dropped that much in 3 days, i would try with a new battery first, its the cheapest thing to try