Hi ,
I have a 2009 XK , not sure if its connected but day after changing battery in key fob the car started fine as normal, travelled about 5 miles made a stop got back in car and it wouldn't start.
All exterior lights were flashing erratically but no ignition or dash lights, called the breakdown man out , he checked battery which was fine and ended up resetting car by holding battery connections together for about 20 mins car then started as normal, two days later same problem again, again solved the same way .by the way the breakdown man plug it into the computer but it showed no faults at all ., still no warning lights on dash and car has yet again failed to start today with the same problem.
Has anybody had this problem before or any ideas ?
Thanks in advance for any replies
Ray

 

This could be a lot of things, but I would start with the key fob itself. If the connection to the battery is not firm the fob can work intermittently or not at all. See this thread, particularly post #17.

No guarantees, but worth a look IMHO.

 

Could also be another case of deficient main battery. Also recommend a reading of any diagnostics codes.

 

Thanks for your quick reply, i will take a look at thread, incidentally i have two key fobs and the problem happens with both

 

Hi ,
Had a life time guarantee battery on it so had it exchanged just in case , according to the breakdown mechanic the car came up with no codes or problems when plugged into his diagnostics

 

In that case it is unlikely to be a problem with the fob. Remote keyless entry has its own module, located below the right-hand A-pillar in the footwell, whether your have a right- or left-hand-drive car. I am not sure that accessing it will tell you much, except perhaps if you see that there is a wire loose or broken to/from the module.

You said that the car showed no diagnostic codes. Were the codes read after this problem appeared? If not, a simple and cheap way to get most of the codes is to buy an OBDII code reader (tons of them on Amazon) that pairs with an IOS/Android app. Well worth the few dollars/pounds/euros/shekels/pesos/etc you pay.

 

Just because you had a new battery installed doesn't mean that it's fully charged. New batteries can sit on the retailer's shelf for months, slowly discharging.

I noted that you recently joined the Forum, so welcome and congrats on making an excellent choice.

Electrical problems are a common complaint. Often the culprit is a weak battery - particularly if your car is not driven daily. Cold, winter temperatures also adversely affect battery performance. To avoid battery problems, many Forum members use a quality battery maintainer. One popular choice is the CTEK brand. I recommend that you consider buying one. There are many threads about models and installation choices.

 

He had a new fob battery, not main battery hence my response in post # 3

 

Use a voltmeter to check the available voltage across the battery terminals with the ignition in the OFF position. There needs to be a minimum of 12.6 volts available for all vehicle systems to function correctly.

 

I agree with you, and wanted to tell him about a battery maintainer, as it might be the solution to his problem. He has two Smartkey fobs and the problem happens with both fobs. His technician did a hard reset on his car battery, but that didn't fix the problem. I wasn't sure if his "lifetime guarantee" applied to his CR2032 fob batteries or his 12V car battery or both. I mentioned the 12,V battery because so many different electrical gremlins are caused by a weak 12V battery.

 

Further to all the good information already provided by others, I can tell you from experience that the flashing of the exterior lights on the XK is the final gasp of life of the battery. Much more commonly experienced are the random warning lights or malfunctions from any of the various modules in the car related to windows, convertible top, touch screen, door locks, seats....it can be anything - all of which are caused by low battery voltage. But the flashing of the exterior lights (and/or sounding of the horn) is the marker of a battery asking, no, pleading desperately to be put out of its misery.
As has already been stated, a new battery is almost never fully charged so charging it fully is job#1 when installing a new battery.

 

Don't think it could be the fob - you say neither works. Are you able to lock / unlock the car using either fob? If you try to start it (foot on brake pedal / start button) do you get a message on panel "smart key not found"? I ask because I had another go-'round with the keyless entry module in my 2010. Unplugging / plugging in connector brought back function. It's located, as mentioned in previous post, by right side foot-well.