2014 Ford Fiesta Eco Boost Intermittent central locking and other electrical issue

[FordOwnerIsh]

I have a 2014 Ford fiesta eco boost and I have had this issue lately. The central locking does't lock unlock both by using the key fob and or the central lock button inside the car. The passenger side window and mirror stop responding using the controll on the driver side but the passenger side window always works using the passenger side control. The turn signals that show up on the driver dashboard is super glitchy, sometimes doesn't even blink at all. All of these issue happen from time to time but last couple of weeke it seems to be happening more often than not. When they do happen it seems they all happen at the same time.

I took it to a fairly well know garage near me when I was facing the issue but when they were trying to diagnose it, everything started working again so the garage just took my money and asked me to come back when it stops working. They did say that saw some fault codes but couldn't do much when everything is working. I have attached the fault codes. Not sure where to go with this it seems like they wont be able to do much unless its not working. Would geting an OBD scanner help in this situation?

 

[SyntheticAtmosphere]

No, purchasing an OBD scan tool will not give you the answer you are looking for. A scan tool gives you information to help diagnose a problem. Without being able to interpret the information the tool is useless.
The first possible culprit would be a bad ground. When a ground connection becomes compromised it can affect electrical flow which in turn affects the various systems ability to communicate. Based on the codes you have showing it is possible there is a bad ground in the drivers door wiring. This may also be a failed/failing component within those circuits. Corroded connectors also can affect electrical flow.
Another possible culprit would be a broken or compromised wire or section of the harness. Power interruptions or fluctuations can occur or worse yet, crossed wires. This is common where a door connects to the car as repeated flexing of the harness happens as a door is opened and closed over the life of the car.
The next step would be to break out a wiring diagram and multimeter.
However, if the systems are working normally finding the issue is near impossible. The garage you took the car to wasnt lying, gremlins are the hardest to chase down.
What I see...
Battery voltage code @ the Drivers Door Module(DDM) paired with the lost communication with Body Control Module(BCM) and MedCAN code. The DDM communicates with the cluster (door ajar lamp ect) and the BCM ( for various features...interior lighting, locking, windows, mirror adjust and heating etc.). In this situation it is possible the DDM is providing corrupted communication to the cluster and BCM
The issues with the ABS and GPS are possibly related but not culprit by being on the same CAN network and are affected accordingly.
This is an off the cuff interpretation of the information you provided. Are you capable of continuing with diagnosis?

 

[Handy Andy]

Working more with @SyntheticAtmosphere approach...

The speaking of Broken Ground wire is quite plausible - and you can do some simpler checks using a simple flat blade screwdriver to help lift trim and inspect a grounding point as there are several in the passenger compartment - with two at the front, one on the passenger-seat side and driver seat side.

These are where Ground wires from the main wiring harness route to and are soldered to a lug that then bolts the wires tied bundle lug to the frame ground.

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Since these seem to be intermittent - they may be caused by vibration and rusted metal that makes/breaks/makes contact for grounding wire points.

It may also signal a bad door seal or windshield seal is failing and you/re getting water entry into the passenger compartment and its' corroding the wiring and affects the electronics due to the terrarium effect that trapped water tries to evaporate away and the compartment won't let the water drain or escape So it collects and thru temperature changes and dew-point - it condenses on the electronics and accelerates the problem.

Might need to do some digging.

If you use the AC a lot (Defrost/Defog) then the AC weep - condensor drain port is bent/kinked or plugged and water drains into and stays in the carpet.

If you can - and you have a garage, park the car in the garage with the car windows open so it can dry out - see if this can help clear the problem and then get after those ground points they may be corroded and need some TLC.

 

[FordOwnerIsh]

Thanks a lot for replying so quickly @SyntheticAtmosphere @Handy Andy .

Sorry for getting back to this late. I had a quick look at the ground points on both driver and passenger side and they look clean, although they only had one wire connected to them. I haven't had a chance to roll the window to dry the window compartments yet, so will give that a go. I have not been using AC that much recently but did use it during the summer for like a month.

I will probably have a dig around at ground points to make sure they are tight and good. I think I should have a multimeter lying around as well, so might give it a go after digging into the wiring stuff more. But do feel like I am better off taking to the garage whenthe issues arise again.

 

[Handy Andy]

There are several "ground points" even in the engine compartment...

So they are located under (or by) the Brake Booster (that master cylinder and it's booster) you will see two bolts with a pair of wires - bolted to a "tab" that is welded to the firewall - it acts like a bond point for some special ground returns the harness uses to bind a set of sensors, modules and battery (by using the Frame that the tab is mounted to) together to ground as a return to help simplify the wiring and let fewer wires pass thru the bulkhead into and route to the Body Control Module or to those bond points shown earlier.

So once "common ground" is established - the wiring signals clear themselves up - as long as the battery's own ground bond is good to both the battery and to the frame.

To help with location - this thread might help!
https://www.fordfiesta.org/threads/2015-ford-fiesta-low-beams-intermittent.8405/post-21940

I guess I can't stress this enough because for the glitches these things can generate - a simple re-tightening of a bolt can go a long way - but this also requires due diligence too. Its a constant battle to keep the ground potentials found between the Engine block, frame and the battery - all a low as possible in ohmic resistance present so all can work and sent signals and communicate without a lot of noise or eddy ground currents changing the values by a load being applied changes the ability to read data present on the system can vary by several tens (not tenths - Tens as in a factor of 10X) of amperage draw due to the steering assembly rack is motorized, by electrical servo and so it needs electricity in both voltage and current demands to meet the torque and the rotational speeds demanded and needed in everyday driving. ABS/TRAC control is also asking for this power just to help with braking and steering - between these two - the PCM needs to see clear data; not embedded in noise or lost due to excessive current draw dropping the voltage present in which to send this data..