Fixing the Vauxhall Flashing “S” of Doom…

Yes, that’s right. If you have a Vauxhall with the Aisin-Warner AF13/AF20 FWD Automatic gearbox, and are experiencing the flashing “S” indicator fault, your gearbox is being harsh and feels like it’s stuck in 3rd all the time, and generally your automatic isn’t being automatic, you may find help here.

My 1997 Astra 1.6 automatic has been a stunner, but in the colder/wetter days it had a minor sulk. It started fine, but the minute you moved the Selector to Drive or Reverse, the “Sports” indicator on the dashboard starts to flash, and the gearbox computer goes into “limp” mode so you have to change up and down gears by hand as it sits in 3rd if left in Drive. Plus it’s harsh on the changes in this mode. Invariably, it feels like the “Snow” mode is engaged.

It’s been doing this on and off for about 8 months. Usually, a “Switch car off, shift repeatedly from “P” to “1″ and back, restart” cycle clears it. It quickly gets tedious.

You can still drive it fine by hand, but it’s not why I bought an automatic. Sometimes it takes a few miles of manual shifting before the “turn off” cycle works.

Anyway, I’m sat here one bank holiday Monday, and I decide to say “stuff to it” and remove the gearbox selector switch, as it’s usually this that seems to give the problem. Loads of money from Vauxhall, and apparently “not serviceable”.

I’ve seen people remove them and I’ve seen another guide to cleaning and regreasing the Volvo owner club seem to have a recurring problem with these, and they use very similar gearboxes. Possibly FIAT use it as well (unconfirmed). So, armed with both sites and my Haynes book of inaccuracies (and believe me, for the Astra-F facelift model, it IS inaccurate), I decided the time had come to do a guide from experience.

So, without further ado, lets get the bugger off, shall we?

Removing the selector switch
Tools Needed:

* 12mm Spanner/Socket
* 13mm Spanner/socket
* Cable tie clippers
* Adjustable wrench
* Flatblade Screwdriver(Broad)
* Switch Cleaner (Maplins is good)
* Nonconductive Grease(again, Maplins is good)
* Flat blade screwdriver (Jewellers), or toothpick or similar
* An old stiff bristled toothbrush

First, open your bonnet and familiarise yourself with the bay. Mine is an X16SZR 8v engine, and the AF13 autobox.

Engine Bay

The autobox selector switch is this lump, here:


The selector switch is held in with the marked bolts, that you will be removing (You may also wish to remove the negative off the battery..i did.):


Now, Haynes says to put the box in Neutral. However, it also tells us that the autobox dipstick is in need of removal as it is attached to one of those bolts.
It’s bunk, at least on this engine/box. However, neutral is as good as anything, so do that. Looks like I did mine in Park.

Break out your 13mm Socket or spanner. Then, carefully undo the nut marked “1″ in the pic, and lift that selector link off the pivot. Leaving you with this:

Switch Arm Disconnected

Now, time for the adjustable wrench, i have no idea what size this nut is. Remove (gently) the nut marked “3″. You’ll need to unbend the locking tabs. recover the nut, the lockplate and the rubber washer. Leaving you with this:

Now, disconnect the switch wiring. You may need to cut a cable tie that bundles all the wires together to enable removal. Follow the wires from the switch, and unplug them at their connector by levering the red bit of the connector out sideways to release the plug. it’s also clipped to the bracket..a sod to remove, but keep trying.

Once that’s free, Break out the 12mm socket/spanner and remove the bolts marked “2″. They are stiff, and go with a crack sometimes. Mine did!
Once those are out, use your fingers and gently wiggle, persuade and lift the entire switch upwards to get it off the selector shaft. Remove it from under the bonnet. Leaving you with this:

Now, this is important. Refit all bolts loosely into their locations on the box, so you know where they went. It’s just easier.

OK, it’s out. Now what?

This is where you’ll have to excuse me. I brought the switch indoors to an easy clean place..the bathroom. So, once i’d evicted the cat and grabbed some cardboard, lets see whats what:
One switch:

One switch upside down.

See that? in the upside down shot, there are 6 philips screws holding this switch together. Remember – “non serviceable”. More like “want your money”.

Remove the 6 screws. You *may* have to bend the bracket at the wiring end to enable you to split the switch seems to clamp it shut. Bit of a bugger, but done carefully it won’t hurt.

Now CAREFULLY open up the switch. The selector “arm” inside has 3 spring loaded contacts..don’t lose them! Mine were gummed in place.

There we go, all opened. Note the seemingly tiny amount of yellowed grease in there! Those copper strips are your gearbox’s a simple unit.

Some closeups of the manky grease and muck in there:

You can just see the rubber switch gasket stuck to the base..remove it carefully and put it to the side

That groove is where the gasket should sit on reassembly.

Now, break out an old cloth and some switch cleaner, and get all that old grease out. The grease seems to carbonise and solidify between the copper strip contacts, so you may need to use that jewellers flat blade and the toothbrush along with the switch cleaner to dig it all out of there.

To clean the “arm”, I gently removed the copper contacts and toothbrushed the rest using lots of switch cleaner, followed by a wipe down with the rag. Don’t snag the springs in the process!

It may not be needed, but after it was cleaned up, I gently polished up the copper strips and the arm contacts with some fine sandpaper, which we keep in the loo. (doesn’t everyone?)

The results!

One degunked, scraped and scrubbed switch contact set, after polishing with sandpaper. Nice and clean!

One degunked, scraped and scrubbed switch arm, after polishing with sandpaper. Nice and clean too!

Once cleaned to your satisfaction, break out the lube and lube it all back up! It needs to be high temperature, nonconducting grease..this stuff from maplin is like silicone sealer..thick, sticky, slippery, and should be fine.

I used my fingers to lube up the contact strip..spreading loads on and pushing it into all the valleys between the contacts, and smearing it over the copper. On the top half of the switch, I put 4 large blobs of it and spread it about evenly to cover the whole inner surface.

I also used my fingers to lube up the contact arm..the grease holds those copper bits in place when you reassemble the switch.

Once everything is greased up to your satisfaction, push the arm back into the switch housing, refit the gasket to the groove in the top cover (i used a dab of grease to hold it there) then manipulate the top cover back into place, making sure the arm, contacts and gasket stay put.

Now refit and tighten up the screws again.

There you go, switch done. Now refit to the car in the reverse way you removed it. You may need to move the switch positioning bit around using your fingers to get it to slide over the spindle on the box, but it’s easy. Make sure you bolt it up with the bolts in their original place or as close as you can to that. I used the dirt to see where the bolts had sat before!

Once back on, tighten up the bolts and reconnect the wiring. If the selector lever isn’t in the right position for refitting on the switch, move the selector in the car until it is, and refit.

Post installation operation check

Now this is important.

* Reconnect the battery, if disconnected
* Handbrake firmly on.
* Put the selector in Park
* Turn the key to position 2, but DO NOT start the engine.
* Move the selector slowly through all gears..does the flashing “S” light come on? If it does, the switch may not be your issue. Mine doesn’t anymore. Hurrah!
* Now put the selector into reverse.
* Get out and check your reversing lights have come on.
* Shift to any other gear/neutral/park
* Get out and check your reversing lights have gone off.
* Check again, to be sure.
* Stick it into park, and start it up
* Check you can also start it in neutral, but not in any other gear (pick somewhere with space!)
* With the engine running, try shifting through from P to 1 and back a few times – should be no fault light.

All good? Hopefully so. If so, should now have some respite from the “S” of doom..we’ll see how it goes on cold mornings! Fingers crossed.

Note:When you took the upper section of the switch off during disassembly, did you see the small “blocked off” tube hidden in the wiring channel, and the small hole inside the switch that it leads to?

I do wonder if this is a “grease” point, where more grease can be injected into the switch without need for removal..

Or, it could just be a breather..but why a switch should need one, i don’t know.

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37 Responses to Fixing the Vauxhall Flashing “S” of Doom…

  1. Bob says:

    Cheers for that. it sorted my GF’s astra.
    BTW, the big nut is 22mm.

  2. Brian says:

    Fantastic! The ‘S’ of doom was problem a while back but not so much now, but: Son’s Corsa now being a bit iffy to start when in P or N unless you do the gear stick shuffle a few times then off it goes. Been dreading pulling this unit apart as (It’s non-serviceable) of course! Yeah right! Thanks to the great info, I’ll have it off tomorrow!

    All the best.


  3. Roy Dawson says:

    Thanks for this i’ve just spent a few hours ( took my time ) and sorted it, cheers !

  4. doug says:

    ta very much. worked a treat on 1996 1.4 corsa

  5. doug says:

    ta for that sorted my corsa 1.4 works a treat

  6. Tony Fidler says:

    Ive had the same problem for nearly 3 years now with my vauxhall astra, i finaly braved it and followed your great detailed guide and would like to thank you a 1000% it solved my problem with the flashing S of doom and also my reversing lights never worked till the car had warmed up, all of which are working from cold now and no more flashing S of doom, many many thanks, your the best.

    P.S. wish id have done it sooner, hehe but better late than never !!

  7. tony m. says:

    I did what was said on this site and it didn’t work for me. Is there another way to reset the switch?

    • Karl says:

      Not that I know of. The flashing S is a general fault lamp though…you need a diagnostic tool (look for OPCOM on Ebay, I use mine with a laptop all the time) to read an in-depth fault report and that might help ID what’s upsetting it..

  8. mark dijkens says:

    Hi Karl,

    Thanks so much for this tutorial! I had the same problem on my wife’s P reg Corsa B – and the ‘s’ light kept on flashing while engine loosing power. I followed your tutorial step by step and managed to put it all back together. I had to remove the battery all together to remove and reconnect the switch. It works like a dream and we have had no problems since. The repair shop told me a new switch would cost over £300… THANK YOU! All the best Mark

  9. Required fields are marked * says:

    Thanks for the tutorial, followed a link to here off the MK3OC, just took mine off and tore it down today, just gotta clean it up and re-assemble. Once again thanks for the tutorial.

    I put up with the light all the time the car was on the road, soon as I don’t need it anymore I end up sorting all the wee niggles out.

  10. Dan Stobbart says:

    1. Top notch tutorial , excellently written and superb photos. TTL for peeps like you !!
    2. That mysterious black tube in last photo… if you rip the metal cap off , there’s a foam bung which you can slowly blow through .. I guess it’s to equalise pressure so the rubber gasket on switch doesn’t blow when auto hot ? Shiny metal cap is to stop it blocking with engine grime ? It’s hidden & inaccessible under that annoying metal bracket (photo no 9 … at the right end of the wriggly cable cover). I removed the bracket completely so now my black rubber tube is exposed , any time I want I can pull it off and squirt in some WD40 or more silicone grease (maplins do it in spray cans as well as tubes) … the spray tubes go right through the hole to the middle of the switch. …….. Thanks again Karl.

  11. Chris says:

    Thanks for your effot putting up this tutorial! you saved me heaps…. it was a job the repair shop had no clue, I won’t be going there again!

    Thanks Chris

  12. Paul says:

    Brilliant repair,sorted my Astra 1.6 8v auto out,saved me £285,many thanks.

  13. John says:

    I wish I had tried this before consulting the Daily Telegraph’s ‘Honest John’.

    His diagnosis of the problem was condensation in the automatic transmission fluid and the solution suggested was to replace the fluid (and ATF ain’t cheap!!).
    I did this but the flashing ‘S’ light problem remains.
    So now it’s time to get the spanners out and overhaul the switch.
    But what I don’t understand is why the switch gives trouble in winter but not in summer.
    Anyone know why?

  14. paul says:

    what a great well explained tutorial, my daughters 2005 1.8 astra car has the symptoms you discribe but without the flashing s, running it backward and forward through the gears certainly got it going again but only after it had been sitting for a couple of hours so weather her fault is tempeture/distance related i don’t know, but certainly ok for a while when left,
    any way really appricate someone tacking the time to put the work in to help out the rest of us poor slobs who don’t know mechanics.
    thanks paul

  15. Mihai-Andrei DAN says:

    Greetings from Romania Karl and thank’s for sharing your know-how with us!
    I bought my ’96 Vectra x16xel automatic from Germany in 2008 and every winter I had this issue with the car.. I was suspecting that it should be a minor thing and tryed to test the car for fault’s but everytime i drove tot the mechanic the fault dissapeared leaving me for nothing to test, but now i know exactly what to do!

  16. gary hick says:

    you r a star, followed your step by step instructions i,ve now got 4 and 5 gear working you are a proper diamond many thanks

  17. Mr J McCarthy says:

    Thanks to this webpage & My Friend Glenn (Mechanic) My Corsa 1.4 LS Auto (High Torq) is sweet as a more Flashing “S” of doom..reversing lights work a treat like a new car!
    took him 15 mins (he is an expert)thank goodness was going to buy a newer car…!

  18. Eddie Cox says:

    Thank you, thank you & thank you. That irritating ‘S’ light has been flashing on now for 6 years!!!!!!!!!
    6 years ago I was quoted £225 + vat + fitting and setting up.
    Yesterday 14th May 2012 I was quoted £315 + vat + fitting and setting up.

    I went out bought the ‘Maplin’ products £9.50, started at 10am and had it back on and working by 11am. Your advise has saved me at least £500. If you are ever in Brum drop me a mail and I’ll buy you a well deserved pint. Cheers.

  19. Eddie C says:

    Thanks only been a problem for 6 years!!!!!!!!!!

    If your ever in Brum drop me a line I owe you a pint at least!

  20. jodie says:

    THANKYOU SO MUCH..took me an afternoon..getting the cable tie to cut was the hardest part..saved me $580!!! you rock!

    • Shuaib says:

      Hi. My astra is doing the exact same thing, taking of in 3rd gear only an the sport light flashing,I overhauled the switch and even tried another, but its still stuck in third with light flashing. , could there be something I’m missing or could there be another problem. I’f I select 1 and 2 manually. It drives fine

  21. Sherly says:

    this worked a treat! no more flashing S baby! your detailed pictures & instructions enabled me (a girl) to do it! amazing! However I think i may have done something wrong? (though i followed the instructions to a T. My problem now, after doing this, is that it starts temprementally? I have to rock to gear lever from P to 1 & back before it realises it’s in park & starts. It’s like i’m trying to start it in gear (i’m not) but it wont turn over unless i get into P properly and push the lever as far up in P as it will go? where/what did i do wrong. When i get it going it’s goes fantastically, no more sluggish limp. Just the starting problem… Hmmm

    • Karl says:

      Sounds like the switch needs loosening and rotating slightly to bring the Park sector “on” as it were…if you’re not in Park or Neutral, and the switch isn’t in the right part of the tracks, it’ll stop the starter motor. :)

  22. PJ says:

    Wow, i just read through everyone elses testimonies. I have an L reg 1.4 Astra with this problem. The little car got us through 18! inches of snow with its snow socks fitted in December 2010 and when its timing belt spat off 6 teeth it was fixed for £16 pounds and ran better after even getting 7 mpg improvement (honestly) which has somewhat endeered us to it. Sadly the S light came on in August last year and we parked it up since then in the hopes of getting it fixed. I have the switch off and I am now going to get wd40 to releasee the 6 screws…. hope to come back here in the next 2 days with good news. Either way it goes thanks for your posting…. you could teach haynes a few things.

  23. Robin says:

    I have an M reg corsa 1.4i auto, part of the family from 12k miles, now on 150k. S light flashing started about 5 yrs ago, intermittent but more temperamental when cold. Had many diagnostic ‘experts’ consider the problem with many suggestions. I have overhauled the head, changed g/box oil, had a few sensors replaced, all good for maintaining system life, but still flashing S remained. Finally tackled the selector switch as outlined here last weekend, what had I got to lose ? Guess what, no more flashing S light, even in these cold temperatures, been ok for a week now, I now have a smile of real satisfaction that this switch has been the problem all along, but no more !

  24. Danny Elliott says:

    Great tutorial, I’ll give this a try soon. “s” light has recently started random flashing and power loss on the wifes P reg corsa. Has anyone had the engine electronics light coming on intermittantly? (the yellow light with an engine symbol and flash). Mines doing this also.
    A bit more forum seaching on this and i’ll try the strip down
    thanks :)


    • Karl says:

      Engine light..could be anything. Look on EBay for “OPCOM” – it’s a diagnostic unit you can plug into a laptop and read the car sensors/logs with…it’ll tell you what’s wrong, and give you something to go on for a repair. :)

  25. Marius says:

    Good day i have an 97 opel astrra 180ie automatic but my reverse lights dont work. Ive been to opel but they cant tell me where the reverse switch is situated. is it situated in this switch u cleaned. Marius Cape Town South Afrika

  26. Martin says:

    You are brilliant,
    Not for showing me your method along with excellent pictures, but for leading me to the root of the problem and fixing it without even opening the bonnet.

    This particular 1995 Astra 1.6i had the typical flashy S which was temporarily remedied by stopping and restarting. Once healed, it could be invoked again by selecting gear 1 or just waiting a day.

    The important point is that this car was used “Rarely” by an elderly gent.

    With the engine off, grab that gearstick, pull up the indent lock and slide the stick all the way down to 1 and all the way up to P (bumping the endstops) 50 times or more like your trying to pump the water out of a sinking boat. Be rough like you hate it!

    Sliding switches should be self cleaning. But copper builds up a non-conductive oxide layer after a while. And if it’s not worn off then there’s your potential problem.

    If pumping that stick like a pro fails to work and you need to disassemble the switch then don’t be too anal about the cleaners and greases or where you get them (Maplins is just overpriced tat for semi-techs) Meths, petrol, surgical spirit will all dissolve the old grease and gunk but the new grease as you rightly point out, should be an insulator, definetly not something like copperslip.


  27. Mark says:

    I have a problem my goes into limp home mode I have a 1.8 ZAFIRA auto and my car runs fine then all of a sudden it loses power as if its in snow/ice mode I lose sports button and ice/snow mode but can get all gears by changing it manually so I may have to service the inhibitor switch like you lot thanks

  28. Robin says:

    I did the full works as detailed here last November 2012 (see my note earlier), but sadly the flashing ‘S’ has come back just the same, worse again when cold ! Not sure really what to think, but as it was ok for a while then after cleaning, may give it another clean again soon. Perhaps I will pay a bit more attention to all connecting plugs in the same area, give them a good clean aswell.

  29. rami says:

    hi i had the same problem but without (s) sport flashing ??? what can i do

  30. Shuaib says:

    I have done the above but the problem still persists. I have fitted a different selector switch as we’ll, but the gear is still stuck in 3rd with the light flashing.

  31. terry says:

    do you have to reset anything after cleaning the switch ? been told will need opcom after cleaning

  32. mpilo says:

    Is this ‘S’ flashing caused by cold weather? I have a 1999 opel vita stuck in one gear and ‘S’ flashing but its being used in the hot conditions of Southern Africa!

  33. Tom says:

    Invaluable Karl, my son Mark is having a problem with his old Corsa auto at the moment so I am going to mention this to him. Will let you know results when I hear from him. Do you know anything about Power Streering on a Corsa B by the way? Best wishes to you. Tom

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