Hi - I started getting a parking brake fault message today but the brake is not on and the car runs fine. When the fault is not flashing the brake engages and disengages fine. When it's flashing the brake won't engage but the car can start and run fine.

Ive seen posts of faults with the actual module but those posts talk of grinding noises and the EPB being stuck engaged. Not my issue so Im assuming an electrical fault? Ive read some who suggested to reset the car by removing the battery cables and touching the + - and letting sit for 10 mins (others have said just to remove the -.

Additional info: it rained the sunroof leaked + the kids were washing the car when the fault started flashing. Im wondering water leak on a wire somewhere?

Any recommendations appreciated. I've lost my patience on this 2016. My 2009 was amazing but the 2016 is nothing but problems.

 

Well, the water ingress issue only you can decide. Undoubtedly with the switch directly below the sunroof…
Or, your battery needs replacement. You have insufficient voltage and
/or current supplied to the vehicle and systems of least importance will not power up. TPMS is one of those early systems.

 

thanks! so u think it might be battery related? can you check an undervolt condition with a obd reader?

my sunroof doesn't leak down on the EPB switch itself, it leaks into the passenger floor boards, typically passenger side. we had a rain storm the other night and I didn't get the drains cleaned out in time. I usually do every fall before the rains come in SF, but we had an early storm. it happens every winter on both my LR3 and LR4 and never seen this fault.

do people see the switch itself failing?

 

some more info on the issue:

- i checked voltage with the multimeter. battery voltage with engine off was 12.6-12.7, with engine running it when to 14+. that seems normal I believe.
- I checked voltages in the OBD reader but was confused by what it was showing me. it has a "ECU voltage" and "OBD Module Voltage". OBD Module volts showed 13.7 at idle, ECU voltage showed between 14.4 and 14.7 at idle, but when I would increase throttle it would decrease to 11.9. im not sure what those readers are and why they decrease when you increase throttle.
- when I got in the car today the light park fault light was not on. I let it idle, I turned the brake on and off with no issues a few times. however when I turned the heat on max, which is the same thing that triggered it yesterday, the fault came on again soon thereafter. any ideas why that would be? I thought maybe the heat would decrease voltage and that correlates to the comment about it being a low battery situation. but I only saw a small change in volts at the battery with the heat on vs off, like 0.1 volt difference.
- I took the F9 fuse out of the glove box (which is supposed to be related to the EPB). no change and didn't see any issues with the fuse.
- I took the EPB fuse out of the main fuse box near the battery. that killed the flashing fault light but created a solid yellow brake light in the dash. (I was wondering if I could just disable the EPB and fault light for now because I don't use it anyway.)

so stumped. any recommendations appreciated.

 

A couple of thoughts for you
1. The battery has a maximum voltage capacity. Any thing above that (as in when the vehicle is running) is the charging voltage provided by the generator and integrated voltage regulator (american terminology: alternator)
2. The engine starter and the HVAC fans and compressors are the most aggressive electrical components. By turning these on, or on high you are making a lessor voltage available to other modules.
3. Apologies, I don’t recall your model year. If a year that is configured for an Agm battery, and you have an agm battery, this capacity is larger than the lead-acid equivalent. A lead acid has a max capacity of 12.6. Using lead-acid in a vehicle with a bms will result in ineffective management. And ineffective useage.
4. Modern day generators and bms (and ecu) manage and adjust charging to accomodate load BUT if the battery has a lessened capacity… what’s the point.
5. Replacing the battery with a new, not old, fully charged battery is a must. Replacing a failing alternator, bms modules, etc are possibilities.

But, i don’t subscribe to musical replacing parts. Yes, I change the battery frequently. But proper pinpoint tests are needed for other components.
And it just so happens… one of the first issues experienced with a failing battery… epb and tpms…

And finally… the success of the epb circuit is necessary for many systems. Pulling the fuse is an old school, not understanding modern electrical systems workaround… that doesn’t actually work. No hard feelings!!! Just saying it as it is.
cheers!!

 

thanks @guy and yes
"And finally… the success of the epb circuit is necessary for many systems. Pulling the fuse is an old school, not understanding modern electrical systems workaround… that doesn’t actually work. No hard feelings!!! Just saying it as it is.
cheers!!"

I get it and agree. I was more curious about a) if those fuses were bad and b) what would happen when I removed them .

Im going to get the battery tested and go from there.

 

@thebruce , Thanks for inspiring me to catch up on my “entertainment” reading.
I found these good articles:
https://www.expedition-parts.de/en/b...n-discovery-4/
https://www.expedition-parts.de/en/b...eim-discovery/

 

@guy more twists and turns in this saga, but it looks like you were right:

- I brought it to orielly to have them test the battery and their machine said it was fine. However the guy asked me which one was negative...so I took it with a grain of salt.
- the light had been off for the past few days but I was just replacing the thermostat and had the heat on 100% again, and instead of the parking brake light, I got a terrain response error light.

So your comment seems to be confirmed.