Apologies for starting another thread on the same topic but I didn't get any replies to my Mk 8 ST specific query.  Having looked at the wiring diagrams, it seems any 2016 onward Fiesta owners with the FORScan diagnostic app may be able to confirm whether the following FORScan info is normal or not.  

Using the FORScan Lite app, I’ve looked at live data in the "Dashboard" screen for the PCM and BdyCM modules related to brake pedal operation.  Tested with engine running and car stationary.  In the PCM module, FORScan has a BOO (Brake ON/OFF) PID and a BOO2 (Brake Pressure Applied) PID.  When I press and release the brake pedal, both these remain Off.  BOO “Off” is displayed in red text and BOO2 in green text.

In the BdyCM Module, there are PIDs for BOO_1 (Brake Switch 1) and BOO_2 (Brake Switch 2).  BOO_1 status stays Off but BOO_2 cycles On/Off when I press and release the brake.  BOO_1 is in red and BOO_2 is in green text.

If anyone with a 2016 onwards Fiesta and FORScan can check whether they get the same results, I'd be really grateful.

Thank you.

Bump.  Can anyone help with this?

I did try to help but you ignored my suggestion. See one of your other threads.

32 minutes ago, unofix said:

I did try to help but you ignored my suggestion. See one of your other threads.

Apologies unofix, I didn't ignore your suggestion about a switch fault.  I removed the switch and tested the switch itself which appears to be ok (one switch open/one closed, depending on switch operation). 

The cable to the switch connector is very short so I wasn't able to remove one of the pins to the suspect side of the switch without stripping parts of the lower dash to get access.  I didn't want to run FORScan with the connector removed as I'm nervous that disconnecting both switches would trigger fault code P0504 and I don't want Ford to walk away completely if they suspect I've been tinkering with the car. 

Do you still think it's worth getting access to the connector to remove one of the wires to the suspect side of the switch and running FORScan even though the switch itself appears ok?

29 minutes ago, Malvolio said:

Do you still think it's worth getting access to the connector to remove one of the wires to the suspect side of the switch and running FORScan even though the switch itself appears ok?

Hi Derek, since your not getting any answers to your question regarding the signals then my suggestion would be to remove one wire from each of the switches (one at a time) and see if FORScan notices the non-functioning circuit

If you physically remove the switch assembly would it then be possible to run some temporary wires between the switch and the connector to give you more length ?

I suspect that it could be a timing issue between the "make" and "break" of each switch. Testing the switch as you have done has proved the contacts change state, but it wouldn't be possible to tell if they swap states at the exact same time. How critical the timing is for the detection of a fault I've no idea.

Thanks unofix, good idea to use some temporary wires.  I'll give it a go.