[508 MK1] EPB Problem, No communication with ESP ECU [U1213, U1219 & C155A, C1552]

[EliC]

Hi! It's going to be a long story, since I tried a lot of solutions and I would want everything I did to be clear to whoever is going to help. So thank you for who is going to read that

I have a 2013 508 SW 163 2.0 HDi MT with EPB
2 months ago, the parking brake lh cable got twisted in itself, what made it stuck inside the sleeve. there was a lot of faults after that happend:

It took some time and a lot of cursing & welding, but long story short ( I would just add a photo showing why effort was needed) - I replaced only the cable with an aftermarket cable coming from a manufacturer in Poland.

Now, I connected the OBD to my laptop using the Diagbox software.
I took the steps as shown in this video, from 8:55 to 15:10


(I'm adding here the steps:
1. setting the parking brake to disassembly position (release the cables)
2. calibartion of the parking brake (it activate and release the motor a few times)
3. turn on the engine
4. scan and clear ESP faults (U1219 is shown on this step the same as in the video))

in my case, I could use the parking brake ONCE after that step. and then I got the following faults immediately:

ESP: U1219 (error automatic release of EPB)
EPB: U1213 (No communication with ESP); C155A & C1552 (no calibration and fault in force sensor)

When clearing the faults, U1219 and C1552 clear. But, C155A (calibration) and U1213 (Communication) stays on, no matter how many times I try to erase them.

I tried to apply the EPB from the actuator test, and it doesn't always work, unless I do all the process I wrote before - again. so when applied - I do get a value from the force sensor (image attached)

so I'm not sure there's a problem with the force sensor sending data, but rather it all the same fault - something with the communication between ESP & EPB.

my logic here is that the force requested is depend on values from the ESP ECU, so if there's a fault there - the EPB doesn't know how much force to apply.
from here, i'm stuck with a mechanical working EPB, but an electrical fault neutrilizing it.
I searched everywhere and couldn't find any solutions for my issue, I could only find people with the same issue, replacing parts and still get no solution. I guess they did evantually, but they never updated their threads :

[mickthemaverick]

I would advise you thoroughly check the electrical plugs and earths around the ESP ECU as it seems to me that various problems may be the result of a poor ground.

[RichardW]

The comms fault is almost certainly a result of the other, force sensor, fault.

In your pic of the data it's saying force on the cable is 1350N, whereas the requested is 0N - this is most likely the problem. I don't know how it works, if you set the brake in the service position, does the force go to 0? Is there an option somewhere to re-set the force?

[EliC]

The requested force value is displayed only during activating the handbrake button, and it stops when the button is released.

[EliC]

I would advise you thoroughly check the electrical plugs and earths around the ESP ECU as it seems to me that various problems may be the result of a poor ground.

I now remember I washed the car a day or two before everything happened... maybe some water stayed on the connections and did all the mess.. (although it's HOT over here)
Do you have any information about the ground location?

[EliC]

OK after looking after all the grounds and terminals around the fuse boxes, and everything look good. I researched during the night and reverse searched the photo of the motor to find more information... you can always trust the Russians for that. I found 2 posts about the force sensor in drive2, here is one:

https://www.drive2.ru/l/659393616925429920/



Now i understand the role and the way the force sensor works. It make total sense, that the force sensor is having play. Therefore the ecu recognize something is wrong and shut off the communication. I guess that the problem initially caused the motor to keep pulling the cable even though the calipers were locked, and therefore it twisted the cable and ruined it!

When I opened the case I found that a black plastic piece was broken, it held against the motor and the white plastic of the force motor.

I didn't thought it is too much necessary so I didn't glued it right away, that's my mistake!!!!

I guess it keeps the sensor in place and it should move only when enough force is applied so that the spring is compressed and move it a little bit so the ecu can recognize there is enough tension in the cables and stop the motor.

Long story short- i would open the case again, glue the white force sensor plastic and hope it would fix the problem - and I wish it would help others that would have the same situation...

[EliC]

Update: the broken plastic of the force sensor was the problem.



thats it.. everything work good!!!

I would upload a full video in a couple of days, since i guess a lot of people would be having the same issue and could fix it with not a lot of money