curious problem with key fob working /not working and not detected

[Van substitute]

Hello Everyone I was wondering if anyone else has experienced funny goings on with their key fob for the jazz hybrid.
I am having one of those intermittent problems that seems difficult to pin down. Some days the remote fob works fine others it doesn't ( for locking unlocking) Then having got in the car I need to put the fob on the start button to get the car going sometimes  (others okay) I have had a dashboard orange warning showing the fob with a diagonal line through it which according to the manual means the key fob is out of range even though it is sat in the drinks holder about 15 cms from the start button!
Things tried .....I actually put in a new JCB battery when this problem first started thinking the warning mentioned above was denoting a weak fob battery whereas in reality this is indicated differently with the fob symbol and a icon adjacent showing a partially charged battery.
I measured the voltage today its is 3.02v whereas the other fob has a Kodak battery and is 3 v exactly with no problems so it looks like this should be okay. Anyone had problems with different brands of batteries even though they are new just don't cut the mustard ? Or is the fob itself faulty which I would think is a rare problem but may be not . Any helpful comments, advice or pointers welcome.

[Marco1979]

Did you check for corrosion on the metal parts where the battery is inserted? It might be that moisture caused some corrosion and that can prevent the battery from functioning optimally.

[dayjavoo]

I had a similar problem when my Mk3 Jazz was indicating low battery in the key fob after a ridiculously short time like a couple of months after putting in a new battery.  I tested the supposedly exhausted battery and it was good, round about 3V.  I cleaned the contacts in the battery compartment with a cotton bud dipped in isopropyl alcohol, although I couldn't really see any corrosion or dirt.  I put the old battery back in, the low battery message went away and the key fob now seems to be using batteries at a normal rate.

[Lord Voltermore]

Both the JCB and Kodak brand names often appear on Chinese made batteries sold in discount stores. So the brand names alone are not a guarantee of quality.   But as both give at least 3v   it may not be the cause. 
I think the key responds with a  passive radio signal  that doesnt need  a battery anyway .   But it might be subject to some form of radio interference.

Is the problem confined to just one of the keys, and the other works ok?  In particular is it confined to just one driver  who might for instance have more than one keyless fob on their keyring, or carries other security passes etc that might respond to interrogation radio  signals from the car.    I think that GPS signals can also  cause interference. Maybe from a  smartphone?    Also keys that are used regularly  can get quite greasy and dirty  from handling. Maybe this could  affect the return signal strength.   Is the cars main battery in good condition?    If its giving out less than 12v  the signals it is sending to the key may not be strong enough to generate a good passive response from  the keys microchip. 

But i dont know. These are just suggestions, all of which may be wide of the mark  .

[Van substitute]

Did you check for corrosion on the metal parts where the battery is inserted? It might be that moisture caused some corrosion and that can prevent the battery from functioning optimally.

Hi Marco 1979  Yes i checked the battery and wiped the contacts but they were shiny and bright.

[Van substitute]

I had a similar problem when my Mk3 Jazz was indicating low battery in the key fob after a ridiculously short time like a couple of months after putting in a new battery.  I tested the supposedly exhausted battery and it was good, round about 3V.  I cleaned the contacts in the battery compartment with a cotton bud dipped in isopropyl alcohol, although I couldn't really see any corrosion or dirt.  I put the old battery back in, the low battery message went away and the key fob now seems to be using batteries at a normal rate.

As my rely to Marco i did check for dirt but i can try the alcohol thanks.

[Pine]

Best to avoid cheapo batteries and stick to the main brands or supermarkets own.  I put a cheap one in the fob last year and it didn't even last 3 months, whereas the original battery lasted in excess of 2 years.  My quality replacement is still going strong after 9 months and I expect it to last a lot longer.

[Van substitute]

Thanks Lord Voltermore  for your suggestions . I will work through some and see what happens. Interestingly you mention other radio signal devices. I have a garage door fob on the same key ring which also seems to have been eating batteries more quickly than should be right. Even though they have been together the whole time its something to try.

[madasafish]

I suggest cheapo batteries are to blame.

My 2012 Jazz is on its original key batteries  (Both sets of keys work perfectly)

[aphybrid]

Thanks Lord Voltermore  for your suggestions . I will work through some and see what happens. Interestingly you mention other radio signal devices. I have a garage door fob on the same key ring which also seems to have been eating batteries more quickly than should be right. Even though they have been together the whole time its something to try.

I have both also but no battery problem, one car fob battery changed at just over 2 years old