Just wondering if anyone else has had intermittent electric faults on their ford fiesta 2016. Sometimes the battery + engine + oil light will flicker at the same time briefly and the voltage drops to 12V from 14V at the time the lights flicker. It's done it whilst accelerating and whilst stationary. The car revs on its own when it happens and if it happens whilst driving in lower gears the engine can jolt at the same time. Auto electrician cannot find the fault as it's intermittent. My car mechanic doesn't know either.

Anyone got any thoughts? Thanks!

I'd have the alternator fully tested

My thoughts would firstly be with the wiring and connector to the Powertrain Control Module (PCM). If that is fully inspected and no problems found then my second thing to check would be the Body Control Module (BCM) and look for signs of water ingress and/or corrosion of the connectors.

On 6/25/2025 at 7:59 AM, DaveT70 said:

I'd have the alternator fully tested

Thanks that's helpful, I have been told the alternator is charging, but it's hard with it being intermittent, the auto electricians I've seen want to charge hundreds of pounds to take it apart. But the fault seems to be improving this week so I'm hoping it's going to go away. We'll see

On 6/25/2025 at 11:54 AM, unofix said:

My thoughts would firstly be with the wiring and connector to the Powertrain Control Module (PCM). If that is fully inspected and no problems found then my second thing to check would be the Body Control Module (BCM) and look for signs of water ingress and/or corrosion of the connectors.

Thanks for help. Is this auto electricians who do this? Who would you go to? Currently the fault seems to have stopped mostly so I'm going to watch and wait 

3 hours ago, Abi_fordfiesta said:

Currently the fault seems to have stopped mostly so I'm going to watch and wait 

See if the fault occurs more when it has been wet weather.