I wonder if Ken is hoping one of us can post bail...

In the meantime, more Dad jokes to keep his thread alive:

What do you do with a dog with no legs?

 

Wait twenty years then nail it next to a 20 year old cheeseburger?

 

Denied! Not even close.

What do you do with a dog with no legs? Put on his leash and take him for a drag.

Goodness, Ken needs to get back soon...

 

My ignition cylinder seems fine.

 

I happen to like Dad jokes

 

Ok. I needed to see enough good data to comment on what I've done. I haven't seen a fault in a while now. New, plain old Lead Acid wet cell battery, charged and conditioned a few times, and she charges right up to 12.8v and stays above 12.6v reliably. What did I do? I made sure my Bluetooth OBD adapter was disconnected. Yes, I said I had disconnected it the last time the battery seemed to run down, but I forgot I had reconnected it to pull another code (unrelated to this, I'm getting too rich codes from the downstream O2 sensor, bank 1). I've since had it sitting in my cuphilder, and the car sat for 2 days, and read > 12.5v. Took a short deive and it read 12.83v. Fussed with the batteries (I can't escape electrical issues) in my mom's RV, and 4 hours later it still read 12.68v.

I'm going to take the Bluetooth gizmo apart, apply power to it the same as the OBD port, and see what it tries to do internally. I'm not saying this is the culprit. In fact I'm now trying to prove it isn't!

Wet trunk is a big problem, btw. Get that sorted asap. Way too many computers under the floor

Ken

 

There's a video on YouTube on hot-wiring the brake.

https://youtu.be/8xebdRYwtjE

Ken

 

Welcome back. Hope your time in the slammer wasn't too bad.

Don't be too harsh on your Bluetooth OBD gizmo. It's not really designed to be left installed all the time. And the car's power supply to the OBD port? That's straight from the battery, so it's not really designed to have something connected all the time. Two conflicting designs, and you end up with a slightly drained battery and a parking brake fault.

Here's my latest cockamamie scheme:

Look at sections 20.1 and 20.2 in the wiring diagram. It looks like the OBD port is called the "Data Link Connector". Pin FC1-16 is the hot battery supply, via fuse F6 in the Primary Junction Box. To confirm this, install your Bluetooth gizmo and turn on the ignition to power it up. Then pull that fuse and see if your scanner connection goes dead, to make sure we are dealing with the correct power source.

Next, you can leave the gizmo (sorry for the overly technical terms) installed but with the fuse removed, drive that way for a few days, and see if the fault stays away. If so, you can have your cake and eat it too with the following mod:

Install an ignition-switched relay in that wire. With the ignition on, the gizmo gets power as normal. Shut off the ignition, and power is removed. Operation will be fully automatic and you can leave the gizmo installed all the time, but with no more drain with the engine off.

Also, please run that voltage drop test as described in post #95. The problem may be solved in increments, with a little here and a little there...

 

Been raining here again, so I'm happy to test it when I get a little respite from the wetness. Until then, I'm enjoying not having PBF. So far, charging looks great, and voltages have always been above (usually, WELL above) 12.5v. The AutoZone battery has been added to my backup battery rack, where it'll live out its days.

I still am not brave enough to let the valets park it yet. Once I can rule out any other stray loads or weird crap like "the wipers didn't park, so the rain-sensor kept the XYZ module awake", I'll let the valets touch it again...

Ken

 

If you had to hazard a guess about why the car now seems to behave, what comes to mind? Maybe a combination of the new battery and unplugging the OBD gizmo?

 

Unfortunately, it isn't behaving. Just this morning, I had to take my son to school - 20 minute round trip, about 8 minutes of which were highway, the rest surface streets. Got home and, not thinking, I let the car automatically set the parkbrake. When I came back out to take my other son to school, about an hour later, I got the dreaded Park Brake Fault/Cruise Unavailable error. Upon checking the voltage, I logged 12.28v.

Edit (edit, again): after I disconnected the battery, it recovered to 12.55v. A .27v drop. I also took an amp reading before disconnecting, and it read slightly over 3A. During the run-down test I did, the battery lost .01v every ~1 minute with a 4A load applied, so from an average of about 12.7-12.8v that I've been seeing after drives, an operating drop to 12.28v in one hour corresponds pretty closely to a 3-4A constant drain.

Things that were different:

1. it's been raining the past 3 days
2. I noticed that, when it's just a light drizzle, the passenger-side windshield wiper doesn't seem to be able to get itself down out of the speckled portion of the bottom of the windshield. I don't know if this is a failure to park, but I flag this is a difference because I've seen people having problems like this that keep the module that controls the wipers awake.
3. when I hotwired the brake to unwind it, I - at first - applied positive voltage to it, and I heard the motor hum. Turns out I must have set the brake even more, because after 20 minutes of a disconnected battery, I still had the fault, and the brake was still set. Confused, I hotwired it again - this time with reversed polarity, then I heard the motor unwind the brake and the car lurched a little.
4. I couldn't get the PB fault error to go away. My scanner couldn't log into the module to clear the fault.
5. (Another Edit) I was parked nose-up on my driveway, which is sloped. I usually back in this time of year, to keep my clogged sunroof drain from dumping water in my rear driver-side footwell. It wasn't raining when I returned, so I pulled in and parked normally.
6. (More Edit) I notice that the vehicle message center prompts and justification (left aligned, but tabbed in one stop vs. centered).

Differential analysis:

1. There has been a strong correlation between the season and whether this EPB fault happens. I had it all winter last year, and it went away around April/May (when the weather dried up). Wet EPB motor/connections?
2. Non-parking wipers seem to keep lots of other modules awake. Not sure of the correlation, though.
3. H-Bridge in the EPB motor controller is failing or wet. Almost half of the truth table for a typical h-bridge circuit results in a short of some kind. With mosfets, there could be leakage caused by a failing component as well, and N-channel devices are generally used for ground-switching and the gate is pulled low to activate.
4. Has the EPB module failed? Is there something that is shorting on the motor side (there are a number of sense lines that could be shorted: CA256-7, 12, 10, 13). The power to the motor is not ignition switched, and the module must stay energized for some period after the key is removed, to handle winding the brake, sensing where it is and stopping.
5. Perhaps the hill-hold feature is a culprit. My sloped driveway could certainly register with the vehicle tilt sensor, and it might be keeping the EPB module energized. This does not explain the many times when it faulted on me on perfectly flat ground, but those could be caused by the battery not being well-charged (because AGMs' lower internal resistance, etc.)
6. Did all of the disconnect/reconnect cycles of the battery cause the instrument cluster software to revert to a previous version? If so, what else might have reverted?

After driving to work, voltage was 12.68v at shut down, after the headlights timed out (10s on my Auto setting), which probably was enough to knock the surface charge down.

OBD module might have been a red herring. I can say for sure that I don't have a weak or undercharged battery any more. I need to rule that out. This particular instance seems like it can only be caused by a high quiescent drain. This should be pretty easy to diagnose if it has something to do with the EPB module itself. Access to the module and the connectors is pretty easy, and I think I have a simple use-case that can be reproduced readily.

Ken

 

Looks like you have a drain.

So far it appears you have nothing to say it's the EPB doing it. And it may well not be.

(But it upsets the EPB.)

 

Wow, Ken, my head is spinning after reading your latest post. Still sounds like you are hot on the trail, only somebody keeps moving the trail.

So I gets to thinking...

The intermittent nature of the fault is amazing. You could keep experimenting and gathering data, but with one very irritating drawback. Every time the fault returns, you (or the valet) are stranded until you rig up your hotwire to retract the parking brake.

What if you rigged up a special temporary inline harness and switch arrangement as your hotwire? Put the switch in an accessible location, like the side of the trunk or in the spare tire well. Then you can safely drive as normal and continue to gather data, knowing you won't be stranded if the fault returns. When you get the dreaded message, instead of removing liner panels for access, you just flip a switch and be on your merry way.

I don't think it would take much work to create a simple harness like this. It could be installed inline by separating the connector feeding the actuator. Years from now, when you or your descendants finally find the root cause, you could remove this temporary harness and reconnect the connector directly.

If nothing else, you deserve a medal for perseverance. Want a little encouragement to keep at it? Years ago at work, we had a particular long-range international plane with a chronic generator problem. Just one plane out of a fleet of about 20 had this issue. One of the engine-driven electrical generators kept tripping off when taxiing to the runway, and they'd come back to the gate. Not every time, of course. Never happened in the air, only on the ground. Multiple parts had been replaced, and analysts had been all over it, directing us to check this wire and that.

Eventually a coworker noticed an obscure correlation that led to a permanent fix. When this naughty plane left for an international destination, all was fine. When it flew a shorter domestic leg, that's when the problem occurred. Initially we thought it had to do with the fuel load and the flexing of the wings affecting a generator feeder cable, as the plane carried much less fuel on shorter trips. Much time was spent investigating that, to no avail.

The final clue was when we considered how the multiple generators were configured on the ground versus in flight. On the ground, an additional generator was used and then typically shut off before flight. We thought we were hot on the trail, but still couldn't find any fault with this aux generator. Much serious headscratching took place, believe me.

So why would a generator act up on the ground, but not in the air? It was a combination of the generator configuration on the ground, and believe it or not, an oven. On long trips, the flight attendants didn't start the ovens until airborne and the aux generator was off. On short trips, with less time to serve meals, the flight attendants started the ovens at the gate before pushback. A bad oven was backfeeding an AC signal into a DC control circuit. Somehow it found its way back in the aux generator control circuit, as the engineers never considered this obscure possibility. The final fix was to replace the bad oven. Who'd have thunk? So keep at it. I, for one, don't think you're crazy. But please consider my jumper harness idea to reduce the frustration factor.

 

Ken,

Your issues sound similar to my STR. So far
1 - lots of issues
2 - indy garage couldnt solve it
3 - replaced motor, then indy thought the calipers were sticking (so motor was unnecessary, but I had already bought it)
4 - 17 months of no issues
5 - EPB faults start happening
6 - one indy greases up a caliper, no fix
7 - another garage replaced a cable, fixed for 2 months
8 - another indy greases everything up, no fix
9 - same indy replaced motor, no fix
10 - indy above tells me to replace the battery, which I have done, no fix

 

Ken,

Any updates?

How's prison food?

 

Got a PB fault a couple days ago. It was the dreaded liquor store robbery scenario:

- Starts fine, then short(ish) drive
- Stopped to get something from the store, and I shut OFF the headlights, HVAC, and Radio, and let the EPB set normally.
- Spent 5 minutes in the store, came out and it PB faulted. Voltage was low at 12.3v
- Hotwired the brake motor to release, finished my errands.
- Got home, cussed the car. The apologized to it because it's so pretty. I'm shallow, I can't help it.

Put it on the charger and disconnected the battery overnight. Next morning everything was fine. Zero correlation to wet weather, since we were sunny and dry.

I'm not sure the charging system is able to charge at a high enough current with the headlights, HVAC, Radio and seat heater (and intercooler pump, etc.) on.

So, let's recap:
- New battery? Check
- Quiescent Drain? Nominal @ 25mA
- Charging System? ?

As Sherlock Holmes said, "Once you've eliminated the impossible, whatever remains, no matter how improbable, must be the truth."

I need to get serious about testing out the alternator and other components of the charging system. I'm also considering installing an ultracapacitor in parallel with the battery to handle startup load. Seems like it would be useful for that short-drive scenario as well, since UCs charge up so fast.

Ken

 

Okay Ken,

Before I go any further, I should clarify the salutation. I mean that in the sense of "Okay, I've processed that information, and am now calling you by name to get your attention as we more forward towards a solution." I do not mean that in the sense of you being merely a mediocre person, for instance to differentiate you from a Superb Ken, a Pretty Darn Good Ken, or a Respectably Above Average Ken. Moving on...

Reading back through this sordid mess, I see my TheoryDuJour™ in post #95 was never adequately addressed. It was a two-part theory, so you should feel extra special. Part one was the possibility that the ignition switch was not fully returning to the ON position after being released from START. You addressed that, but not part two:


https://www.jaguarforums.com/forum/s...5/#post1847363


Scenario #2 was high internal resistance in the ignition switch, with a carefully designed and oh-so-simple voltage drop test to confirm the conductivity of the switch. I did not see any reply after #95 indicating that test was ever run.

In addition to my previous comments in post #95, also note the seat heaters get their power through the same pole of the ignition switch, and then through fuse F16 in the primary junction fuse box. If the switch contacts are marginal, that extra load would cause extra voltage drop, which in turn would affect the EPB module. It would take you all of 5 minutes to run that test...

 

How old are your discs?

The 11th step for my issue is to change the discs, but too early to comment on if this has fixed the issue. My discs were ~4 years old, heavily worn on the outside but apparently a complete rusty mess on the inside, so my indy is confident that is the final fix......

 

Ken,

Any updates for this most epic thread?

Still wondering if you tried the vo!the drop test called out in the second half of post #95...

 

Ok, I'm back. Seasons turn, and it's drying up here in the PNW. Also, the EPB issues have gone away. I swear to you it's either the cold temperatures or the rain. It doesn't get actually "cold" here, unless by "cold" you mean "wet". I haven't checked the voltage drop of the ignition switch yet. I'll do that this week. I noticed, though, that the car won't charge the battery past 12.8v. My wife's Nissan van will happily bring the battery right up to over 13v, and will charge it at 40Amps. Admittedly, this was after a child left something on and it drained the battery, but I don't recall ever seeing a charge current like that from the Jag.

Current contenders:
1. High resistance/marginal contacts in the ignition switch.
2. The switch in the end of the lock barrel (which actuates the driver memory stuff and seems to get some of the computers warmed up) is faulty. This has some merit, and has been discussed here on the forums quite a bit.
3. Wipers aren't parking correctly, keeps wiper module awake.
4. Water ingress past the leaking cowl seal has gotten into something. If a signal wire is shorted to ground, it'll take that input pin low - which is how the inputs are triggered on our microcontrollers - which can keep stuff awake. I already know I have a water leak there, because a knock sensor freaks out when it rains really hard or for a long stretch.
5. Faulty EPB module.
6. Insufficient charge current or voltage. Seems unlikely, since the system seems to handle high beams, seat heaters, wipers, HVAC blower, and intercooler pump without missing a beat.

Did I miss anything?

I've added a semi-permanently installed hall-effect sensor and voltage probe to the battery compartment, with an OLED display in the trunk. All I need to do is pop the trunk and look at the voltage and current drain. It doesn't log, but it has a coulomb counter that gives me a good idea of charge/drain summation. Been hooked up for a couple months now, so I need to have a look and see what the Net Amp-hour figure is.

Ken