2019 Fiesta SE no start

Greetings all,
I am seeking info to try to assess the no start on my Fiesta. It was an auction car, so maintenance, etc is suspect. The car was running when I picked it up. It was very low on fuel and I filled up the tank. All the usual suspects of purge valve and/or canister have been ruled out (replaced the purge valve). I just picked it up from a pretty decent mechanic-he could not find the problem. The things he went through: drained the gas tank and replaced the fuel pump, checked for spark (good), compression is good.
In looking through the suggestions here: I checked the F25 fuse (good), horn works and tried starting in neutral; all to no avail. The engine sounds like it wants to turn over, but won't.
The only other thing to add would be that both brake lights were blown. It probably was a fluke, but odd that both were out.
Any suggestions would be greatly appreciated!

Do you have push button start? Have you fully charged the battery and then load tested it? Did you have any other MIL or strange behavior of the audio system or hvac just prior to the no start event? Just to be clear, no start means you tried to crank the engine and the starter cranked but the engine would not fire?

No, I do not have push button start. The key that came with the vehicle looks to be a replacement, it is not a key fob. I would suspect the key, but I drove an hour back home and a couple of errands before it died. I don't think there were any issues with the audio or HVAC. I have the ticking noise in the dash, but have had that on my other Fiesta. Yes, the no start means the starter is engaging, but won't turn over. Also, the battery seems to be fine, but don't think anyone has load tested it.

There is a relay for the Fuel Pump, but it also works the Power train control Module.

Start by reading this thread - it will help work with what is below.
https://www.fordfiesta.org/threads/fuel-cut-off.10480/post-30286

R47 in mine - in the engine bay - also has a fuse to it.


Now, depending on trimline - you can have a big messy wiring system, or the most basic wiring to power the Fuel pump

For simplicitys-sake I'll show the simple one first.

Due to yearly changes - the Fuses and their numbers and location - change.



Then - again depending on your trim line - there may also be a REGULATED fuel pump delivery system - or FPDM that uses a module and several sensors to regulate the fuel pressure in the fuel rail after the pump - using the pump and a pulse mode from this driver module - to control the fuel delivery pressure (Low to High - off then On when pressure drops below a level) else the Fuel Pump itself can do this - using the SIMPLER system.

Because of this type of conversion between the two systems, the Fuses that protect it are numbered differently. Let alone the Relays used - are the same types - but location and their ID references are different.

Where this gets messy, the Body control Module helps regulate the Fuel level display (or manage) the fuel level and on-the-spot Fuel mileage along with Emission systems - your trip and odometer on the pods for example.

• The Body Control Module can also supply the PCM with power as part of an operational Loop in the overall management of the system - which includes a starter inhibit and or Fuel pump cut-off due to accident or as a Security disable to prevent driveoffs.
• You'll need to get at the Passenger side Fuse Box if you need to continue with this diagnostic...
  • Step 1 - Locate and Open Glove-box - remove the contents
  • Step 2 - pull inward on the side panel to release stopping tabs
  • Door and box lowers and can then be removed to allow access to the stuff behind it.

I hope you don't have to go this far for the rest is going into an area that deals with a driver module for engines like Ecoboost and GDi (Direct Inject) which are the ones that use the regulation fuel delivery stuff and gets a lot more complicated.

This is the Fuel Pump diagram with the FPDM module - where the Module in located inside the passenger compartment and is right under the Driver's seat in that seatwell - where the harness for power then goes to the rear seat and the fuel pump is just below the rear bench seat cushion.


So to help with this - the bad part is how the power is sourced for the Engine to run, the PCM powers it, but the Dashboard gets power to run it's own diagnostic and idiot light system separately. Once the system is running then the PCM tells it to light up a specific function light on the dash when something is not communicating with the rest of the vehicle like ABS, TPMS, Traction Control - and even Airbag (SRS). And if it really serious (relative term) it will STORE it in the dashboards own memory until it's cleared thru a DTC-manual intervention or it's self-diagnostic and can shut off the light.

But the Body control module can also disable the ignition thru the use of it's own Ignition relay inside the passenger compartment - that is on the right side behind the Glove-Box and it's door will have to be removed to expose that fuseblock to see it's relays and fuses used for the BCM.

I'll stop here, let me know how or where you need to take this...

Thanks for the reply! So I'm very much a layman in terms of understanding all of that. I am trying to increase my knowledge to figure this issue out. I have just taken out the R47 and replaced it with another relay of the same power to no avail. In your diagram you show accessing the fuse box in the glove box for only the BCM? I assume this is where another fuel pump fuse is? Is You also mention fuses along the way; is that under the seat in the FPDM and the PCM?

Well, it also deals with the type of engine you have.

Are you using the 1.6L 4 cylinder? That's what most of this is based on - a Fiesta like what I've got.

So if you have issues of crank but no start you may have to dig further and find fuses that may have blown - the Passenger compartment one is in case you have to dig further and look at the ignition relay in the passenger side and since you're not a mechanic, this complicates things because you have to back-probe the relay in the passenger compartment to see if it's got a signal from the BCM to tell the rest of the system to run.

Since you have a key but not the fob part, you may be stuck with a bigger bill in having a Ford Dealership assign new keys to reset the system.

Why?

Because that loop they use to secure the system uses RF-ID as a validation - isn't foolproof and requires key-fobs as supervisor keys - so it may think you're in a Valet mode (unsecured) and it won't start until you get the real key with a signal from it to validate and turn off this security function so the rest of the system will see you have a valid key and start will all the systems working like it should.

Why the Crank but no-start? Since the physical key works the tumbler, this is not enough to just "start" the car and run it, to "run it" it requires the security function the supervisor keys provide as an Identifying proper user and over-ride and clear the fault and let the engine run normally. Why the engine turns-over is because of the physical presence on the key in the tumbler and the ignition switch is shorting out the starter to engage the starter-the physical hard-wire to make that work. So the motor turns over but will not start to let the user drive off because it may be missing the other half - a signal - hat tells the system you are the right user to run this car..

If the seller knows how to defeat that, you're going to have to have them fix the car without having to keep seeing them, else you have got bigger issues.

You didn't mention if the Air Bags were ever deployed, and if so, you may have several more issues around it. Why? Look at the schematics above - the Supplemental Restraint System uses a Restrain Control Module in the center part of the floorboard by the Handbrake handle ( YELLOW WIRE with a VIOLET STRIPE ) - if that system fired and sent a signal - it can turn off the Fuel pump because it thinks you're in an accident and it won't clear until the DTC codes that prevent this operational function - have to clear so the fuel pump can even get going again.

Yes, that makes sense and I do have the 1.6 4 cyl. Others have mentioned the key fob situation. I just discounted since I drove 2 places before the no start situation started. The vehicle was in a minor accident and I believe the Carfax noted the airbags did not deploy.
Many thanks!!