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-   -   Red lights come on and stay on. (http://forum.a8parts.co.uk/showthread.php?t=16365)

Simon Wallwork 31st July 2021 02:14 PM

Red lights come on and stay on.
Car is a 2000 model FL S8. 148,000 miles and driven gently by me for the last 10 years.

Today, which was hot c.37c, just as we moved off, the car made a thump and all the 'PRNDL432' lights went red.

Car drives and reverses but no kiickdown and the autobox isn't changing as it used to. It wont kick down or even change down, I think and 'Sport mode' isn't working.

If I switch off, it starts normally and moves off ok (in first I expect) but the change up to second is accompanied by a thump and then the red lights come on and stay on.

Once the lights are on, selecting a "D" or "R" while stationary is accompanied by the same thump.

Is my car a gonner?

edit. Reading through other threads, reverse seems to precede this sort of thing. In my case. all was normal as I reverse parked. The problem first occurred 10 mins later when I drove out of the parking spot.

MikkiJayne 31st July 2021 02:38 PM

Interesting symptoms. Its going in to limp mode which is why it won't change or kick down, but doing it at the change to 2nd gear is unusual.

The first thing to do is scan it for codes. Second thing to do is make sure the TCU isn't wet.

How does it behave in tiptronic? Put it straight in to tip from startup and without moving, then pull away and see what it does and whether it will change gears manually.

Its not the F125, and doesn't sound like a clutch drum as that usually manifests in 1st. I'm wondering whether its a solenoid fault, and that is very often caused by a wet TCU.

Simon Wallwork 31st July 2021 03:04 PM

After reading a bit on here, Tried the car again. No change.

Shut it down, restarted and tried it in Sport mode only. So selected 1 and moved off. box changed up through the gears as requested properly, and changed down properly too. I then reversed to turn. All ok.

Put the thing in "D" and drove home with the autobox working normally and no red lights.

So must be an intermittant F125 fault maybe?

Hopefully not a gonner yet!

Edit to add MikkiJayne, I missed your reply, but interested to see what you think now.
I can't easily scan it for codes as don't have the kit here. Don't think the TCU is wet as its hot here and hasnt rained for weeks. We are in Bulgaria now.

In "D" (when the fault was happening) it started in first, then changed to limp mode gear when it should have been changing to second- but now the thing is back to normal. So whatever caused the problem has gone away!

tintin 31st July 2021 03:20 PM

That does sound like an intermittent f125 fault: I had similar with my S8 a few months back after a period of gentle, and infrequent, use.

The problem went away after some more "spirited" driving, including the use of sport mode, and some "manual" shifting of the tiptronic, so hopefully your issue will disappear in the same way.

PS: I also had the f125 contacts cleaned by my local garage, and haven't had an issue since.

Simon Wallwork 31st July 2021 03:38 PM

Thanks Tin Tin.
Now that I've realised I can 'cure it' by using tiptronic I feel a bit better.

I just paid 1200 quid to have the thing shipped to Bulgaria, so it'd be a right PITA if it croaked on me!

MikkiJayne 31st July 2021 03:44 PM

F125 problems happen when you move the shifter, not once its already in gear and moving.

I still have a beer voucher on a valve block solenoid intermittent code due to water ingress. This is a D2 remember. If Elon wants to find liquid water on Mars he should send a D2 with the scouting party :ROFL: The electronics box is probably full of condensation.

Simon Wallwork 31st July 2021 04:28 PM

Thanks MikkiJayne. I'd best have a look for water ingress then. But where is this electronics box?

I can confirm that the fault does not come when you move the lever. Only about 100 yards after you move off.
The car has been here in warm, dry Bulgaria for a few months, but before that it stood outside in Scotland unused, for 18 months. There was some water ingress to the boot, caused by a perished bung, in the boot gutter side. Is there anything in the boot that could cause this?

MikkiJayne 31st July 2021 04:54 PM


Originally Posted by Simon Wallwork (Post 166070)
before that it stood outside in Scotland unused, for 18 months.


The electronics box is the black plastic lump at the base of the screen on the left. There are a bunch of philips screws holding the lid on which are almost certainly seized in place if it's sat for that long, but worth a try. The TCU sits at the top and is not water-tight, unlike the ECU, so has a tendency to be the first in line for condensation damage. Its a bit of a pain to get to, but if you can remove the connector its worth looking for corrosion there first and giving it a spray of WD40. Sometimes that will help it, but sometimes there is internal corrosion too. Have a look for my General Vod workshop thread - I show the process in there. That one got scrapped for a blown gearbox whereas in fact it was just water-borne deposits on the TCU pcb. I cleaned it with isopropyl alcohol and a toothbrush and let it try overnight and it worked perfectly +++

Btw, I sell replacement boot grommets here: https://www.ebay.co.uk/itm/153918842338


Simon Wallwork 1st August 2021 01:54 PM

Hi Mikki.
Ok, I'll have a look in that box for water etc.
I need a couple of those grommets, so will buy as soon as I have a UK shipping address. We are in Bulgaria and shipping anything here from outside the EU is a pain.
Sorry for late response, last night we had a major storm here and lightning must have struck the mast-thus no internet.
I'm just relieved that its not 'curtains' mechanically for the box....yet. I really like this car.

Simon Wallwork 1st August 2021 02:09 PM

Ok. got the lid off and it's clear there has been moisture in there. very light rusting of steel parts, and typical alumium corrosion, but not much.

I take it the engine ECU is nearest the wing and gearbox item nearest the middle of the car?

It is. Getrieb = transmission!

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