Very Bizarre Electrical Problems

[pennpromo]

Just went to start the 2004 V8 S today and: Reverse lights on all the time, bonnet warning light on, no wipers. GRaphic in display showed yellow car silhouette and a red warning arrow.

Seems like it may be expensive!

Tried to cure by disconnecting the battery under the passenger seat, and managed to break the plastic runner cover as I foolded it back ... All power went off, (so no battery in boot), left it for ten minutes, re- connected and still the same.

Anyone got any bright ideas ?

Many thanks in advance.

[Loren]

:welcome:

Disconnecting the battery is not the solution - the fix is likely a new battery.

If your battery is 4 years old (or older) it should be replaced. A weak battery will cause all kinds of weird electrical problems in these cars.

[deilenberger]

IIRC the instructions in the owners manual on checking the battery very clearly show removing the runner cover BEFORE trying to tip the seat back. It's a tad fiddly to get back on, but way cheaper then buying a new one whenever you check the battery.

[wvicary]

Have the battery properly tested and don't go by the " my headlights are bright, so the battery must be ok " test.

[PKN]

I just wanted to say that the handbook for my 2006 TT does NOT mention the runner cover and I broke one of mine as well....My vote is also to invest in a new battery

PKN

[NelsonMX]

My manual doesn't show the seat runners covers either.......at least you got to the battery!! Anyway, the best thing you can do is have the battery load tested. At least that way you know if it's good or not. By my experience, and as Loren mentions, a bad battery on a Cayenne can cause all kinds of weird problems and messages!!

Bob

[9Bosco]

Agreed. Replace main battery & check it's connections.

Been through a few of the weird electrical things with a dead "under seat" battery.

My Cayenne always started and ran well on just the rear battery...as it should.

[Gstrein]

Since the wipers don't work, look to make sure the bonnet is securly closed and the pin switch is working.

[bleo]

Check wires and connectors in front part, because on some cars cabling gets rotten. Especially when you are parking outside

[pennpromo]

Well an update on the problems. It all went away for a few weeks with a new battery or so I thought:

I booked the car into my local Porsche Centre for a new key (£270, ouch!). Anyway on the way there the gremlin returned so I asked them to look at it.

The diagnosis: rear screen wash hose split, screenweash in the main vehicle ECU, corroded pins and loom. Budget figure to fix £3,000.

I told them to put the parts back together and I would look at it. Collected car, no headlights. My wife used it the next day and the parking barke stuck on.

I went to rescue her, the manual release cable was not connected, easily seen through the fuse board cover. Fixed that and got her home.

So I decided to remove the "A" pillar cover, one screw behind the airbag emblem. Lo and behold a joint in the screenwash hose had come apart, pushed it back together, wrapped some electrical tape over it for safety- five minutes work.

Next a look at the ECU, sure some corrosion of the switch loom pins, three mising and two so corroeded they broke away. An hour with a solder iron and she's all fixed. Cost: 3 hours work maximum and some solder and wire.

So, bearing in mind its a £10,000 car, should my Porsche garage A). have fixed the washer pipe, B). Offered me the fix I did?

Not very happy !

[deilenberger]

It's entirely possible that no one in your Porsche garage has any idea how to use a soldering iron - especially to replace missing pins. They also don't want to be liable for a rework on their nickle (or farthing..) if it doesn't work, so they'll take the safe way out and replace the parts, not attempt to fix the parts. Only old time mechanics and owners actually try to fix parts..

As far as the hose coming apart - well - they should have looked. I'd open it up again and use some tie-wraps as hose clamps to make certain it doesn't come apart again. Electrical tape tends to come apart after time - especially if it gets warm or hot..

Edited December 22, 2011 by deilenberger