How to check if RF is working on key fob

[s5aif]

HI,
When i bought my car i only had one key with it and i am only able to unlock the car using the IR sensor on the door handle. I was thinking could there be a problem with the Fob and is there anyway of testing if it is working correctly. Car is 2004 se c180k.

Thanks.

 

[television]

Just press the button while pointing into a digital camera

 

[Blobcat]

Malcolms test will confirm the IR is working the RF is easy to test although hard to confirm exactly. If you can open the car with the key hidden in your pocket then the RF is working. If not then it could be the RF in the key or the RX in the car that has an issue. Access to a spectrum analyser would show if the key is transmitting although not everyone has a spectrum analyser lying around....

You could check the key out as per Anywebs How To in the DIY section and try and battery swop as quick fixes.

 

[s5aif]

cannot open the door unless i point the fob directly at the door handle and have tried new batteries. Is there any other way to test the key apart from using a spectrum analyser or should i just wait for my new key to arrive. The only problem is my warranty is almost out so if there is a major problem nows the best time to get a fix. If i take the car to MB dealer would they be able to test this out.

 

[television]

looking further it will be the amplifier for the rear window antenna

 

[Blobcat]

cannot open the door unless i point the fob directly at the door handle and have tried new batteries. Is there any other way to test the key apart from using a spectrum analyser or should i just wait for my new key to arrive. The only problem is my warranty is almost out so if there is a major problem nows the best time to get a fix. If i take the car to MB dealer would they be able to test this out.

HI, If you still have warranty then now is the time to get it sorted. If it is under MB warranty then report it now and let them fix it. It does appear that either the TX or RX has failed as you have only one key it is hard to assess if it is the TX in the key or the RX in the car that has the issues.
When the new key arrives you will know more because if that one works you know it is the other key. I would try and pursue the warranty issue in the first instance.

 

[BlackC55]

looking further it will be the amplifier for the rear window antenna

Lovey job to do too. Done a few and quite fiddly.

 

[s5aif]

if this was out of warranty work do you know how much it would cost roughly to fix and would a indie be able to do this as apposed to mb dealer as i think they charge about £90 an hour.

 

[jberks]

The car is under warranty. Report it now, then if it takes a while to solve, MB are still responsible. Does sound like the amp though.

 

[S80]

If you're anywhere near Cambridge I'd be happy to check it out with a spectrum analyzer

 

[s5aif]

Thanks for the offer s80 but i am in cardiff. Also just a quick question does the warranty start when the car is first registered?

 

[Blobcat]

Thanks for the offer s80 but i am in cardiff. Also just a quick question does the warranty start when the car is first registered?

Yes to the warranty, I'm not that far up the road from you and have a Spectrum Analyser just sat on the bench

 

[premmington]

I bought a IR-RF radio tester from Sealys ex eBay for £17

It was to replace my Sykes Pickavant one that does not do 800mhz range (very new cars!)

http://www.remmington.plus.com

 

[alec2]

Any radio ham should be able to confirm if the key is transmitting as it uses a frequency close to the ham band.

But is it transmitting the correct code?

I believe the RF can be resyncd to the car and it could be as simple as this. There is a procedure for this, do a search and you should find it on the web it is normaly very easy. The RF only opens the doors and sets the alarms as does the IR.

The immobiliser is different and cannot be resynced. If this does not work the a new key is probably needed.

Alec

 

[television]

Any radio ham should be able to confirm if the key is transmitting as it uses a frequency close to the ham band.

But is it transmitting the correct code?

I believe the RF can be resyncd to the car and it could be as simple as this. There is a procedure for this, do a search and you should find it on the web it is normaly very easy. The RF only opens the doors and sets the alarms as does the IR.

The immobiliser is different and cannot be resynced. If this does not work the a new key is probably needed.

Alec

The RF locking uses the rear screen as the antenna, this has an amplifier, and as said it is this that goes wrong on 90% of the cars

 

[02 A160 AG]

Any radio ham should be able to confirm if the key is transmitting as it uses a frequency close to the ham band.

But is it transmitting the correct code?

I believe the RF can be resyncd to the car and it could be as simple as this. There is a procedure for this, do a search and you should find it on the web it is normaly very easy. The RF only opens the doors and sets the alarms as does the IR.

The immobiliser is different and cannot be resynced. If this does not work the a new key is probably needed.

Alec

Any information on the resyncing technique? Off to search google now...