Wisconsin Joe

05 CTT, 114k miles.
Battery replaced at dealer by PO 2/14.
Starter replaced with pipes 9/15.

Now that spring is here, I have other cars to drive, so the CTT sits more. It sat for 3 days (locked with alarm set) and when I went to start it, nothing. Dome light lit up, dash warning lights tested as usual, but no crank, no 'solenoid click', nothing but normal relays clicking when turned to on, and a single "click" (again, sounded like a relay) when turned to start. Tried "off then back to start", same thing. Tried "off, pull key, reinsert, start" and it started. Engine turned over as normal. Not slow or labored or anything. Cranked briskly and fired up. Drove it on errands and it started normally each time. Drove it maybe 20 miles, started it up and shut it down 5 times.

2 more days - last night (again, locked and alarm set), same thing, except it didn't want to start. Tried repeatedly. After a few tries got a "Press brake pedal" warning (I was). Then "brake proportioning" and "air suspension" failures (both red). Kept trying and it finally cranked up. Not sure why. Ran it for about 15 min, shut it down. Cranked right back up. Hot post showed 14 volts when running. Locked it up and set alarm.
This morning, same thing. All the warnings and everything. Hot post showed 12.09v not running. Finally started. Again, nothing until it finally decided to crank and then it seemed to crank over normally.

My first thought, being more familiar with the 928, is a relay somewhere. But I know the oddball warnings is a sign of a bad battery. I wasn't able to check volts when trying to crank. I plan on load testing the battery when I have a chance.

Does anyone know what the minimum volts to get it to crank is?

3 years isn't all that old for a battery, but I know it could well be.

Last, the car sits for a week at a time while I am working. Since the parking lot is secure, I don't lock it or set the alarm. Battery has been fine, cranks well all that, after the week of sitting, even when it's really cold.

So...

Battery? Something else? Anything I should check? Have a Durametric.

AO

My first thought is battery. Perhaps try a jump pack and see if it comes to life?

PartsGuyGT

I agree with AO. 3-4 years these days on a battery is a pretty good life span.

Wisconsin Joe

Ok - update:

After sitting for a week while I was working, it won't start.

When I first opened a door (and activated interior lights), I heard a "beeeep" and saw "Ignition lock faulty" on the display. Key wasn't even in the ignition.
Again, when I turned it on, the display lit up like normal, but when I tried to start it, nothing. No crank what so ever. Same "Press brake pedal", "Brake proportioning failure" and "Air suspension failure" warnings when trying to start it.

Battery read 11.78 volts at the jump post.

Tried a new, small, very powerful battery booster (supposedly will start a diesel pickup). It boosted the voltage up a bit (not quite to 12). No crank. Same warnings. The "Ignition lock failure" only showed up intermittently.

Tried a full sized truck battery as a jump. Boosted voltage up to maybe 12.1 or 12.15. No crank, same warnings.

Tried to jump it off of a vehicle. Got voltage up around 13.3, but still no start, still same warnings.

Gave up for a bit, left truck battery hooked up. Came back after maybe 45 min, voltage was up around 12.4. Unhooked battery, tried to start. No crank. Battery voltage dropped a bit each time, ended up around 12.1.

Took bolts out of seat and got to main battery. New in Feb 14, 6 year battery (or at least that's what it says on top).

Tried truck battery direct to car battery. No real change. Tried jumping directly to car battery - jumper cables from running car into my Cayenne and to the battery under the seat. One noticeable difference was that the interior lights seemed brighter.

But still no crank. Still warnings. "Ignition lock failure" would come back after I tried to start it several times. Sort of like the ignition warning only comes on if the battery is even lower. But it's hooked up to a running car and showing over 13 volts.

So...

My next step (tomorrow) is to go back and pull the battery and take it in to be tested. It was dropping pretty fast, even though all it was doing was turning on all the systems in the car. The starter never cranked at all.

And and all suggestions, ideas, encouragement or smart a** comments appreciated.

mtnrat

It will be interesting to see how the battery tests. In my experience whenever I experience weak battery symptoms and have the battery tested it has tested good. I have always finally solved the problem with a new battery. This has happened 4 or 5 times over the years.

touareg

Sounds an aweful lot like what I had: https://rennlist.com/forums/porsche-...-flashing.html

If you dont want to rip the carpet out yet you may be able to test around relay 443.

Wisconsin Joe

Thanks.

The way it just doesn't crank at all makes me wonder if it's the battery or not.

The fact that when it started Sunday, Tuesday & Wednesday it would re-start with no problem makes me think that it is.

I will check out both the wire bundle and relay 443.

touareg

I would get in the car, some days fine, other days turn to acc and the whole thing would light up, errors up the wazoo sometimes car would start other times not.

The wire I fixed goes to a module that is tied into the kessy system, and interacts with all the modules that are on the can-drive bus and causing a multitude of things the freak during "boot".

I think I posted the wiring for relay 433 under the seat. If you slide the drives seat forward all the way you can pull it out from behind and test it. Even after my wire repair, replacing relay 433 has stabilized some things. It is probably a hard driven relay with a heavy duty cycle.

You should be able to test if power and ground are getting to it. Relay 433 is I believe RELAY 15 WITH DIAGNOSIS. I have not traced but I believe A4 is the wire that was broken on mine as I think that module DRIVER IDENTIFICATION CONTROL unit is under the dash. I think that is the module that recognizes and authorizes your key and ability to operate the vehicle along with kessy.

You really should get a diagnostic tool, as you can connect to different modules, pull codes, see the voltage they see on the buss (which helps find low voltage situation due to corroded wiring)

Wisconsin Joe

Well, the reason it sounded an awful lot like what you had is because...

It was that.
You were correct.

<Samuel L Jackson voice>Check out the big brain on Toureg! He's a smart mother...

Fella.</Samuel L Jackson voice>

I had a big pile of snow melt off of the windshield last winter. The snow plugged the cowl drains, so as the top part melted, it ran in via the HVAC.

I thought I had dried it out, but the foam underneath was still soaked.

Got the wire bundle out and it was soaked.

Pulled the stupid "crimped the core and wrapped it with Gorilla tape" connection apart and found the brown/red stripe wire was corroded to "gone", just like yours.
Patched it with a crimp connector. Opened up the other two and found they were ok. Left them and just threw a crimp connector over the bare end so it couldn't short out on anything.

Fired right up.

All the warnings that were showing are gone. It does show a (yellow) "Air Suspension Workshop" warning. Hoping that will go away on it's own.

If not, I do have a Durametric, and can go in and see what's up.

But it started. Video of my happy dance will not be released.

nodoors

If this car sits parked outside and I were a betting man which I am, then I predict the following:

As has been indicated already, you likely have corroded wiring from water ingress AND a battery with a failed cell or two with high IR and self discharging. The battery failure could have resulted from the corroded wiring causing wonkiness in the relays/computers which would deplete it below 100% DOD. Load testing these batteries is almost worthless.

touareg

Awesome! I and my family accepts starbucks gift cards btw.

I am pretty sure the air suspension will clear when you drive the car, just needs to calibrate.

Wisconsin Joe

That's my guess. I had it in "Low", and when I reconnected the battery, it defaulted to "Normal". Some of the other stuff went to default too (lock setting and such).

Interestingly, the clock stayed "on time" and the trip odo kept it's mileage.

Rather odd what stuff resets or 'zeros out' and what doesn't.

Thanks again for your help. If we ever meet, I owe you a cup of good coffee.

AO

Glad to hear the resolution.

mtnrat

Nice!

Wisconsin Joe

Ok, a bit of a follow up:

Car is fine. All error messages are gone.

The water, however, is still being an issue.

To back up a bit:

Last winter (December?) I had the car parked outside at work and it snowed. When I got back, there was a big "blob" of snow on the windshield. It had plugged the cowl drains, but as it melted, the water flowed through the HVAC (I assume). The passenger side was wet, but driver side was saturated.
I used a shop vac to suck as much water as I could, then put a small space heater in for a day or so. I thought it was dry. Carpet was completely dry on top, and even with pressure on it (both pushing with my hands and the normal pressure from my feet on it) it stayed dry.

Well, I was wrong. Really wrong.

The foam under the carpet was still saturated, which caused this. Going at the foam with a shop vac, I got a lot of water out of it. I thought that would be it.

Wrong again.

There is another piece of foam under the carpet, further forward. This is visible in the pics in Touareg's thread. The pics where he details the wire bundle show the foam under the black cable that goes across to the tunnel.

This piece of foam was also saturated.

So more shop vac work, and I have the carpet suspended with a bungee, the foam propped up and a fan under it.

It was both amazing and disturbing how much water had been in there. And how long it was there.