Hi guys,

I have a spare key fob for my R56 Mini Cooper (2009) which does not start the car. Lock and Unlock is fully functional altough.
After a short check of the fobs electronic board, I could find one damaged component, most likely a capacitor.
The problem is that I cannot find out what exact component it is or how much capacity it has.

The following picature shows the damaged key:




Does anyone have an idea which excapt component (or capacitor) this is or does anyone have a schematic of this board? I think it is some kind of RC member, so replacing it with any capacitor may not work.

The PCP number of this board is 233.441.011-02.

Thanks a lot.

 

The PCB appears to have seen some fluid.

Clean off the component area with 90% isopropyl alcohol and a cotton swab. If the cleaned component and its copper pads on the board look okay but the solder joints are questionable, then resolder the component joints. Next, test the voltage of the battery, which I think should be 3V. If that's fine, retest the fob.

Given the fob has partial function but won't start the car, also inspect the solder joints of the large immobilizer chip visible in your picture. How does the coil look on the rear side of the PCB?

 

Thanks for your reply. That what's looking as fluid is the blown capacitor I think. I did clean everything and it fell apart. I cleaned everything and it looks good so far, except that I need to replace it now.
Also the coil looks good.

The battery had 2.82V, I already ordered a new one.

 

Post a pic of your cleaned up PCB in the area of interest.

The missing capacitor is not the electrolytic type that leaks. It's a ceramic capacitor. Did you save the old capacitor because it could be fine.

The comment below from the MINI Key Hospital is relevant to your question.

 

Here is a pic of the cleaned PCP, altough I think that is not what you meant :D
The capacitor did not leak, it did burst. (Also ceramic ones does burst).
It fell completly appart while gently touching, so no chance to get any information about it.



The comment from the Mini Key Hospital does not sound very confident that I could ever find out what size that capacitor has.

 

These remotes are useless to purchase used, as they cannot be reprogrammed once pair to a vehicle. If you are handy with soldering and repairing circuit boards, you “could” purchased a used one for sacrificial components….

 

Or, shoot me a PM. I have one for my donor car. The lock button is missing and I am not sure if it works but I would mail it to you for the price of postage.

Not sure if yours is rechargeable or a replaceable battery but, the one I have is rechargeable type,

 

Good luck with the fix, daxus!

If DogfaceSGM's key fob has a 233.441.011-02 PCB, then you can swap the capacitor of interest onto your PCB.

I also saw some 233.441.011-02 PCBs for sale on UK eBay, but the price of shipping would be high.

 

I saw a YouTube video where ^this issue was overcome by desoldering your current fob's large immobilizer chip and swapping it into a replacement PCB of the same type. However, you'll need advanced soldering skills and tools to remove and install that large chip.

 

Thanks everone for your ideas
That video would be interessting...
Soldering should not be that big deal, so getting a used PCB and take the parts was plan B if I do not get the right spare parts.

As this is the third spare fob, it doesn't hurt that it won't work, but I just thought I give it a try reparing it.

Thanks for your offer, but that shipping could be very high as I live in Europe.
But I may come back to you.

Currently I replaced it with a small capacitor and odered a new battery. Let's see if it does something

 

Below are 5 videos related to your problem. The first of the five is the video on swapping your immobilizer chip onto a used matching PCB (not PCP! :P).