Technical "Brake Switches - Signal Plausibility Failure"

[mattbacon]

So, my 2013 Panda 4x4 TwinAir is occasionally throwing the "Hill Hold Unavailable" "ESC Unavailable" warnings. It was also throwing the "Stop Start Unavailable" warning as well, but a new battery and earth cable seem to have fixed that one. My handy Carly App and ODB connector suggests three faults, all related to the brake switch, of which the last is a B1010-64 "Brake Switch Signal Plausibility Failure" in the Body Control Module diagnostic. I've tried resetting the existing brake switch (RHD, so in the passenger footwell) by pulling out the plunger, putting the switch back in position with the brake hard down, and letting it up again. That fixed it temporarily, but the warnings have come back again. Anyone seen this and fixed it? Would I be right in thinking a new brake light switch is the next step, or does anyone have any better ideas?

Any steer gratefully appreciated....

best,
Matt

 

[Panda IIs]

So, my 2013 Panda 4x4 TwinAir is occasionally throwing the "Hill Hold Unavailable" "ESC Unavailable" warnings. It was also throwing the "Stop Start Unavailable" warning as well, but a new battery and earth cable seem to have fixed that one. My handy Carly App and ODB connector suggests three faults, all related to the brake switch, of which the last is a B1010-64 "Brake Switch Signal Plausibility Failure" in the Body Control Module diagnostic. I've tried resetting the existing brake switch (RHD, so in the passenger footwell) by pulling out the plunger, putting the switch back in position with the brake hard down, and letting it up again. That fixed it temporarily, but the warnings have come back again. Anyone seen this and fixed it? Would I be right in thinking a new brake light switch is the next step, or does anyone have any better ideas?

Any steer gratefully appreciated....

best,
Matt

Probably just low battery volts - these are classic symptoms. Not sure Carly will "properly" read FIAT faults. Give the battery a decent charge and see what's occurring then.

 

[mattbacon]

Probably just low battery volts - these are classic symptoms. Not sure Carly will "properly" read FIAT faults. Give the battery a decent charge and see what's occurring then.

I'd be a bit worried if the battery was already under-charged. It's literally a month old, new Bosch battery, and has been on a few decent runs lately. As I say, the start-stop feature is working as advertised for the first time in years since we got it!
best,
M.

 

[Herts Hillhopper]

I'd be a bit worried if the battery was already under-charged. It's literally a month old, new Bosch battery, and has been on a few decent runs lately. As I say, the start-stop feature is working as advertised for the first time in years since we got it!
best,
M.

Allegedly you need to ‘tell’ the car it has a new battery via the ODB port and MES or similar. This is to reset the battery monitor that controls the stop-start but also affects the charging behaviour of the smart alternator. I didn’t when I changed mine but did (a week or so after) having the alternator replaced. Performing that reset did seem to do something, including making the electric power steering work better.
The combination of warnings and the sequence they are appearing in is a perfect match for the symptoms of a failing battery, as described in many previous posts here (some of which might be listed below in the ‘similar [old] threads’ panel)

 

[PuntoHowTo]

Plausiblity means the readings across the switch are wrong compared with what the body computer expects so you could mess about trying to measure the resistance across the switch, or you could probably get a switch fairly cheap and fit that instead

You’d expect more than that one fault if it were a battery voltage problem

 

[mattbacon]

Plausiblity means the readings across the switch are wrong compared with what the body computer expects so you could mess about trying to measure the resistance across the switch, or you could probably get a switch fairly cheap and fit that instead

Reading the messages in more detail, it looks like the switch unit actually has two circuits, where 1 should be open when 2 is closed and vice versa, and the plausibility problem is that it's not seeing that behavior, which suggests something's broken or badly adjusted inside the switch. I've got a new one, so I'll replace it and see what happens then...
best,
M.

 

[Herts Hillhopper]

Re-reading original past - the ESC, HillHolder and Stop-Start warnings are failing battery indicators and which don’t store a fault code. But I think you mean those errors went away after a new battery was fitted?
The brake switch has two sets of contacts, and I believe are used to detect how quickly the brake pedal is pushed (detecting emergency braking which will open one and close the other switch more quickly than normal braking). Hopefully new switch will sort you there.