UK-POLOS.NET - THE VW Polo Forum

I've a query concerning the two (presumed identical) keyfobs (remotes) with which I was issued when I bought my 1.2 Polo Match Edition around six months ago. The query comes as a result of some observed malfunctioning of the door locks, radio and windscreen wipers in the last 48 hours, after having temporarily used the second of the two keyfobs.

Everything was fine up until the point, two days ago, when I decided to try out the second of the two keyfobs that I'd been given for the vehicle. The decision to use the second one, just for a couple of minutes, stemmed from reading a particular forum query on this site concerning paired keyfobs; the last occasion on which I'd used my second keyfob had probably been on the day I first got the car, and so thought I'd better check that it still worked. Certainly, as far as operating the locks was concerned it did work okay; it locked and unlocked all the doors and retracted and re-opened the external mirrors. I didn't test for anything else. I then returned to using the first keyfob, the one I've been using all along.

It was following that that I noticed that, on the next occasion of activating the doorlocks/bootlock (using one press, I might add) the driver's door (and others) appeared to lock (the red light on the driver's door flashing) but when later I went to the car the red light was out and the locks were actually de-activated! Then, when I got in the car and drove it in light rain, the windscreen wipers wouldn't operate in intermittent mode any longer. Nothing had changed on the stalk. At best, I could only get the wipers to work in slow continuous mode. Then, this morning when I turned the ignition on, a random FM BBC station came on the radio, rather than the BBC one that I usually listen to and which had been configured into the device. Again today, I've not been able to get the front wipers to operate in intermittent mode.

The question I have is whether sudden use of a second keyfob for the vehicle is meant to wipe out driver-configurable settings, and whether the onboard system's likely to get confused if you then revert to using the first keyfob again. In other words, does each keyfob have a specific channel to which is assigned the various driver-configurable settings, and therefore could this somehow explain why I'm now observing these malfunctions? The vehicle's battery is in a good state of charge and there are no on-dash fault conditions being displayed.

I've searched for the fairly recent forum topic referred to above but I'm blowed if I can now find it. It's always the way, isn't it? But I seem to recall that, in that discussion, it was stated that swapping between the two keyfobs requires some sort of synchronisation process to be completed before it'll all work properly. Can anyone put me right on this?

On my TT (made in 2001) a number of settings are paired to which key is in use. Air con, radio volume and so on

I think VW adopted this and youll probably find its the same on the polo. The manual details it on the key page on the TT so i would imagine its the same on the polo.

No mention of any specific allocations to one key or the other in my Polo's owner's manual. In fact, apart from a few explanations of basic things like locking and unlocking the vehicle with the central locking or with the key bit, there's very little information given. There's a short section on one of the pages about 'synchronising' the keys, which apparently is just a matter of inserting each key bit into the driver's outside physical door lock. But certainly no mention of any ability to configure one batch of driver's settings on one keyfob and a different batch on the other.

I wouldn't have thought that any built-in mechanism that assigns a string of settings differently on the two keys would also affect things like the windscreen wipers - but maybe it does?

Not sure what to do at this stage. Would it do any harm for me to actually perform the synchronising, as described in the manual? I'd have thought that when I first picked up the car from the dealer the keys had already been synchronised by that dealer. But gawd knows. If the keys had been synchronised at that time, then the question has to be asked as to how or why they might have become unsynchronised in the interim?

Well my wife has an SEL, so any fancy feature like assigning personal settings to each key should be available with that car, and it is not. I would think that anything like that now only comes with keyless entry.

I think that the deal with a car with two keys is, each key has its own channel, but only for performing the rolling code thing for the engine "dead lock", and nothing else.

Also, so far, I've not noticed or heard of any comments from my wife about issues when she uses her key, this would be a very handy feature to have as it would save me needing to change radio stations or even need to switch the radio off when I use her car!

My oldest daughter's Ibiza should a "high noise level" warning on its dashboard for when I've forgotten to switch the radio off after starting her car.

I doubt the key fobs will hold any driver configurable information.

Firstly I would suggest changing the battery in the keyfob that hasn't been used for a while. They are very fussy on batteries as I know from experience a brand new Duracell wouldn't work and had to get one from the VW dealer.

Secondly, are you sure the car battery is in good condition and what did you check it with?

I think the wiper issue is probably unrelated to the key swop. Do you have a sensor on the windscreen for the intermittent wipe? If so check the sensor/pad on the front screen from the outside.

Stormtrooper1967, you said:

Firstly I would suggest changing the battery in the keyfob that hasn't been used for a while. They are very fussy on batteries as I know from experience a brand new Duracell wouldn't work and had to get one from the VW dealer.

Okay, it may be off-topic by me but that Duracell incident of yours must represent the biggest load of old tosh I've come across in many a year - and do understand that that criticism is not directed at you personally but simply to the screwy concept that it entails. If the required battery cell for a keyfob is supposed to be a 2302 then any battery-cell bought by you or anyone else as a genuine 2302 should comply with the requisite standard for that (which is in all probability an international standard). Across the manufacturers of 2302's, there may be permitted tolerances here and there - for example, in the physical size of the cell, some leeway in minimum and maximum capacity (total AHrs) offered (which would indicate slight differences in the cell's internal resistance), and in beneficial additives to the electrolyte, but for anyone to suggest that only a certain brand of 3v cell will function in a device is frankly bordering on superstition. I say that with my hat on as a retired professional electronics engineer. If your VW dealer made noises that only their 2302 would work in your keyfob then I'm afraid you were well and truly hoodwinked. And yes, you can always place a battery name into a piece of software held on a device or machine but that device or machine cannot tell whether it's actually being powered by that battery or cell or instead by another one of the same basic specification - not unless you want to believe that the very electrons coming out of it are labeled with the manufacturer's name!

I would respectfully suggest that there was some other reason why your Duracell cell didn't work, eg. completely discharged or seriously below-capacity from the outset, poor fit into the cell compartment, wrong fitting by you yourself (often when fitting these sorts of cells into devices, you have to avoid actually handling them with your bare fingers; also, it's all too easy to short the cell out momentarily and not realise it), or even you having unfortunately acquired a counterfeit Duracell cell.

Incidentally, how did you find out that the required cell was a 2302? By you merely opening the keyfob, or does your owner's manual actually specify a 2302? Although my manual describes in very crude terms how to change the keyfob cell, it makes no mention at all of the cell type no. The only way that I myself will eventually discover the type for mine is when I finally have to open up the keyfob, and even then I'd have to trust that the cell I find is truly the correct one and not a stopgap one that some idiot fitted. Is the 2302 known to be the common type used in all fairly-recent VW keyfobs?

As far as VW dealers (allegedly) perpetrating this preposterous idea of a special, unique VW cell but one which is marketed as a 2302 goes, then I can only presume that the 'inmates are now running the asylum'.

But thank-you nonetheless for mentioning the keyfob batteries and for a couple of other things that could need addressing. A keyfob battery (let's keep to the name 'cell') - one of the two concerned here - that's low on remaining capacity is indeed a possibility, the second of the two, as it's the one that's laid around unused for a long time. However, it activated the doorlocks with no problem and the little monitoring light on the keyfob flashed, indicating that the cell was still good. So, it's obviously quite adequately communicating with the receiver on the vehicle. So, I doubt that this has all been due to a failing keyfob cell. As for the vehicle battery, that's in pretty good shape, as I regularly charge it, regularly measure its terminal voltage, and generally keep a keen eye on it. Rain sensor pad? I think not, as I keep the windscreen very clean and nothing's been changed in that area.

I think my observations concerning the doorlocks, radio and the wipers must be unrelated. I'll see how things go over the next week or so. The doorlocks and radio are currently working (or at least, they seem to be), but the wipers not doing intermittent mode is a bit worrying.

Here are one or two further thoughts on keyfob cells.

I've noticed over some decades that on various devices, not just car keyfobs, the design of the contact terminals in the cell compartment has changed. Certain cell manufacturers may have led the way on this quite a few years ago, the change being one where the +ve contact being a spring-loaded tab making obvious contact on to the top of the cell has been removed and instead reliance has been placed on use of the very rim of the cell making contact with the circumference - or even just parts of the circumference - of the cell compartment, the latter being connected to one side of the circuitry. Whether this is how VW keyfob cell compartments are now designed I don't know, as I've personally had no reason to open up either of my VW keyfobs as yet, but it may well be. On other devices, the back of the compartment lid sometimes forms the +ve contact and reliance is heavily placed on the lid being sprung-loaded and the battery height not being undersized.

So clearly, these sorts of changes now put higher demands on the dimensional tolerances. We're talking about minute fractions of a millimetre here. So I could well imagine that if a cell with a diameter on the smaller end of the permitted tolerance were fitted into a compartment whose circumference was a tiny bit oversized, then that rim-type contact might not make. Or in the case of the cell's height not being quite large enough, the cell would fit too loosely in the compartment when the lid was closed. It may then be a matter for the user to find a brand of cell where, consistently, this didn't happen. I do know, for instance, that with a digital watch of mine I always have to carefully seek out one or two specific brands to use with it for this very reason, and over the years I've learnt which ones to avoid. I've usually downloaded the dimensional details from the manufacturer beforehand and online have made made pictorial judgements as to likely physical fit. I've even mic'd some up with a micrometer (using an insulator in between, of course) before fitting them. I've also always used insulated tweezers when installing a new cell into my watch, and kept some IPA (alcohol) and tissue to hand to clean the cell and thereby remove any traces of finger grease before finally slotting it home.

Unless I'm hugely mistaken, VW doesn't make a unique version of the 2302, with special electrical properties. If they do, then strictly speaking it's not a 2302. It might be that VW's tolerancing of the diameter of the cell compartment is a bit on the oversized end and therefore it could be for that reason that only certain brands of cell will work properly in the keyfob. Rum4mo, for instance, has suggested that VW tend to use more Sony cells than other brands.

Although cells bought by consumers on the open market aren't expensive, finding out which brands of cells might have this issue and which might not could, on a personal level, be a little bit expensive. But at least once you've found one that definitely does work in the VW keyfob you need only to stick with that one.

VW 'branded' batteries are generally a repackaged Sony, Maxell or Panasonic CR2032 (or CR2016 in some key fobs). Its nothing special like you say veteran

veteran wrote: Thu Jan 25, 2018 12:55 am [/i]
Okay, it may be off-topic by me but that Duracell incident of yours must represent the biggest load of old tosh I've come across in many a year - and do understand that that criticism is not directed at you personally but simply to the screwy concept that it entails. If the required battery cell for a keyfob is supposed to be a 2302 then any battery-cell bought by you or anyone else as a genuine 2302 should comply with the requisite standard for that (which is in all probability an international standard). Across the manufacturers of 2302's, there may be permitted tolerances here and there - for example, in the physical size of the cell, some leeway in minimum and maximum capacity (total AHrs) offered (which would indicate slight differences in the cell's internal resistance), and in beneficial additives to the electrolyte, but for anyone to suggest that only a certain brand of 3v cell will function in a device is frankly bordering on superstition. I say that with my hat on as a retired professional electronics engineer. If your VW dealer made noises that only their 2302 would work in your keyfob then I'm afraid you were well and truly hoodwinked. And yes, you can always place a battery name into a piece of software held on a device or machine but that device or machine cannot tell whether it's actually being powered by that battery or cell or instead by another one of the same basic specification - not unless you want to believe that the very electrons coming out of it are labeled with the manufacturer's name!

I would respectfully suggest that there was some other reason why your Duracell cell didn't work, eg. completely discharged or seriously below-capacity from the outset, poor fit into the cell compartment, wrong fitting by you yourself (often when fitting these sorts of cells into devices, you have to avoid actually handling them with your bare fingers; also, it's all too easy to short the cell out momentarily and not realise it), or even you having unfortunately acquired a counterfeit Duracell cell.

Incidentally, how did you find out that the required cell was a 2302? By you merely opening the keyfob, or does your owner's manual actually specify a 2302? Although my manual describes in very crude terms how to change the keyfob cell, it makes no mention at all of the cell type no. The only way that I myself will eventually discover the type for mine is when I finally have to open up the keyfob, and even then I'd have to trust that the cell I find is truly the correct one and not a stopgap one that some idiot fitted. Is the 2302 known to be the common type used in all fairly-recent VW keyfobs?

As far as VW dealers (allegedly) perpetrating this preposterous idea of a special, unique VW cell but one which is marketed as a 2302 goes, then I can only presume that the 'inmates are now running the asylum'.

But thank-you nonetheless for mentioning the keyfob batteries and for a couple of other things that could need addressing. A keyfob battery (let's keep to the name 'cell') - one of the two concerned here - that's low on remaining capacity is indeed a possibility, the second of the two, as it's the one that's laid around unused for a long time. However, it activated the doorlocks with no problem and the little monitoring light on the keyfob flashed, indicating that the cell was still good. So, it's obviously quite adequately communicating with the receiver on the vehicle. So, I doubt that this has all been due to a failing keyfob cell. As for the vehicle battery, that's in pretty good shape, as I regularly charge it, regularly measure its terminal voltage, and generally keep a keen eye on it. Rain sensor pad? I think not, as I keep the windscreen very clean and nothing's been changed in that area.

I think my observations concerning the doorlocks, radio and the wipers must be unrelated. I'll see how things go over the next week or so. The doorlocks and radio are currently working (or at least, they seem to be), but the wipers not doing intermittent mode is a bit worrying.

I take your point on the Duracell battery. Fact is that a brand new one from a sealed pack didn't work in the key fob. I took the fob to VW thinking that it had somehow broken or stopped working. VW put one in and charged me the princely sum of something like £3 it worked! So whatever the issue was the VW battery worked whatever make it was. I didn't get the battery back to test it as for the sake of £3 I was just happy the fob was working. I did test the other battery which was in the same pack (twin pack) in another device (not a key fob) and worked okay so it will remain a mystery!

I took the cover off to see what battery type was in already as I couldn't see any reference to it the manual.

Yes, like you say Stormtrooper, it remains a bit of a mystery as to why the first Duracell one didn't work. But usually there's some quite plausible reason why. But anyway, if the VW dealer only charged you £3 for supplying and fitting an alternative then that's not too bad at all, as if you buy these sorts of cells online you'll typically pay £1 - £2 each for them. From a highstreet store or sometimes a supermarket you can end up paying even more sometimes.

There has been some chat about this in the Skoda Fabia forum. (Our Fabia fobs appear identical to our Polo ones.)

The batteries that fit OK are apparently 2025, 2026, and 2032. The 2032 is a little thicker because it has a slightly higher capacity.

Interesting. I'll take a look at that Skoda Fabia forum topic.

Maybe I'd be pre-empting any conclusions drawn from the Fabia forum but I'd say that the important factor is not so much the cell type no. as the manufacturer of the cell and whether the manufacturer has kept to within the agreed specification for the cell (perhaps especially with regard to physical dimensions).

Dave_C wrote: Thu Jan 25, 2018 4:51 pm There has been some chat about this in the Skoda Fabia forum. (Our Fabia fobs appear identical to our Polo ones.)

The batteries that fit OK are apparently 2025, 2026, and 2032. The 2032 is a little thicker because it has a slightly higher capacity.

Maybe I'm wrong, but I always considered that any chat of using a "thicker" and so higher capacity battery (2025 = 25mm 2026 = 26mm etc etc), was aimed at owners with KESSY as it seems that cars with that function need new batteries very frequently.