My Fabia's key fob suddenly stopped working. No electronic lock/unlock; and (worse) the keyless ignition did not recognise the presence of the key. Luckily, I managed to have a new key fob battery fitted before a nearby garage closed for the day. At first, the fob did not work; but after about 20 minutes the fob started to work, and I was able to turn the ignition on. The old battery measured 2.9 volts on open circuit - and I am surprised that the system failed at that. Does anyone know what the minimum required voltage is? Should I suspect a defective fob? Would one expect some kind of indication in unlocking/locking before the fob becomes totally useless?

This incident has raised some serious concerns in my mind about the sense in having keyless/push-button ignition.

Did you have 2 keys with the car? The key fob battery in one of the keys to the wife's Mk3 combi failed recently so I replaced it with a 'new' battery that I had in stock and the fob still didn't work. I went out and bought a premium brand battery and the fob worked immediately. 

I did have 2 keys; but of course (s**'s law) I was away from home at the time, and effectively "stranded",

I think you are correct - it needs a good battery to operate reliably.

At home, I then checked the spare key - the battery similarly read 2.9v, and I intend to replace this with a new one in case the fob requires a higher voltage.

By the way, at the time of the failure I was not aware of the advised procedure of pressing the start button with the end of the key fob - I am told that may have turned the ignition on.

I think the learning here is that one should a) not rely on an instrument panel "low battery" warning, b) check occasionally to see that the red led on the fob lights when locking/unlocking, and c) carry a spare battery and a suitable tool carry out a replacement if necessary.

 

I had low batteries and replacement on both keys changed With new and indicator stopped

 

 

 

The keyless ignition does have a workaround for this. If you take the fob  and use it to press the switch, there's a coil around the switch that can wirelessly power the key up to get you going. Instructions will be in the manual, but of couse most people don't know about this so wouldn't know to look.

 

2.9v is well low. When new they tend to be around 3.2v and stay above 3.0v. Ours went low recently, but we got a warning on the dash. On a previous car (Superb, 12 plate) I never saw a warning so it could be something introduced recently.

My wife's fob has just given up. Fortunately not a keyless system.

 

Back home the spare worked. Swapped batteries around and only the spare worked again.

 

Where do I go from here?

King John,

sorry if this is obvious to you and you've already done it but I've found it's best to remind and to recheck what you've already doubled checked (or think you don't need to check, Sod's Law it's always that). 

 

Have you synchronise the fob to the car.

 

I would always synchronise the fob to the car if a battery has been removed/change - AND if the car won't unlock - it's a very quick and simple procedure (details are in the the driver's instruction handbook 'OPERATING INSTRUCTIONS'  that came with the car -

› Press any button on the remote control key.
› Unlock the door with the key in the lock cylinder within 1 minute of pressing the button.

 

 If you have already synchronised, does the little confirmation check light on the fob light up.

 

Check that the fob battery is clean both sides and that the fob is clean inside where the battery goes and contacts and check the battery is firmly and correctly seated - my wife's last car had a fault where the (GM / Vauxhall) dealership hadn't properly fitted a new battery to the fob as part of a service, you wouldn't think it possible or that it would have that effect but it was and it did.

 

The battery from your spare needs to be a good quality battery and in good charge as it might be good enough for a little used (unused?) fob but not up to it for a very used  and wearing (worn?) only once fob.  The batteries from when the car was new last a very long time but cheap replacement batteries might not.

 

Once you are sorted have both fobs with new good quality batteries fitted and then alternate their use, say every 6 months swap which fob is in regular use, that way you know you will get more even wear out of the set of two fobs and will know that that the spare fob works (and where to find it) and when the fob batteries are getting low.

 

Link to driver's instruction handbook 'OPERATING INSTRUCTIONS'  - http://manual.skoda-auto.com/004/en-com/Model/Fabia_NJ

 

HTH, if not do return and say so, cheers, Nigel.