Jay777

Was wondering what everyone gets for range on their key FOBs. Up until recently, I never got more than 3-5 feet – even with a new battery. No big deal. Anyway, about a month ago I sent my immobilizer and 2 FOBs to ECU Docs to address a problem I had programming FOBs using the ignition key procedure. They swapped out a couple electrolytic caps on the board they reported as leaking, programmed the 2 FOBs and sent it back, noting incidentally that I would see “improved operating range”. Yesterday I did a little test and verified both FOBs now work out to 60 ft from directly behind the car. Huge improvement. The picture below, taken before the unit was sent to them, shows the 2 caps they changed. I didn’t observe any leakage at the time (and still can’t) , but to be fair, I wasn’t really looking for it. I opened up the unit when it came back and confirmed that those 2 caps were indeed changed and it does not appear that anything else was changed. I have no idea what the connection is between the caps and operating range but if replacing them is the sole reason my range increased, it might be worth others trying. The parts are dirt cheap and it's an easy DIY.

nine9six

Hi Jay,
Do you happen to have a link to a quality, reliable source for the parts, and their nonenclature, or are they simply known as
electrolytic caps? Do they have a size or capacity relative to these specific components?

P.S. Would you mind sharing what this fix cost?

TIA!

Jay777

Hey Paul-
They're commonly called “electrolytic caps” or “aluminum electrolytic caps” and are commodity items you'd find at any electronics store. The trick is to find ones with the same capacitance, voltage and physical size (mainly lead spacing). The body style is “radial lead”, meaning both leads come out one end. (Axial leads have a lead coming out each end). There’s an outside chance you’ll find what you need at a Radio Shack, but you'll definitely find them at a place like Digikey. Search for aluminum electrolytic capacitors, then enter the desired capacitance and voltage. I'd be surprised if you couldn't get both for a buck or two - dirt cheap in Porsche Land. I kick myself for not getting more information before reinstalling the unit, but I didn't really expect to post about this. If anyone wants to open a unit and can get me some numbers I'd be happy to look up and post recommended part numbers. I buy from Digikey all the time and it there's enough interest I'd be happy to add a handful to my next order and provide on request.

Still curious what others are getting for range. A 10X improvement for a buck or two seems too good to be true...

IainM

Blue Ocean

I am also at the 5-10 ft range. And often have to be more like 1-3 ft.
Would be curious to see if someone tests the theory here.

Jay777

Thanks for the feedback. Sounds similar to my "pre-repair" performance. I believe I've seen other posts on this forum complaining of short range (and ways to improve it), but can't recall where.
If the increased range turns out to be directly attributable to the bad caps being replaced (this remains to be seen), one would expect all 993's to have gotten this kind of range when new, and that range degraded over time along with the caps. Has anyone seen documentation that specifies the original FOB range?

Churchill

I would pay good money if someone comes up with a way to extend the range beyond 5 feet. My (poor) understanding is that both the fob and the receiver/antenna in the car need to be upgraded. I think the ECU repair place in FL does this but it's something like $700, which is too much IMHO (I'm defining good money as around a couple hundred bucks).

Jay777

If I didn't see it with my own eyes I wouldn't have believed it. Having always gotten 3-5 ft (sometimes LESS) I was absolutely shocked when I measured 60 ft. As I said, this was done from directly behind the car, which was in the garage. I'll do another test from front and sides to see if there's any differences. Further adding to the mystery - the owner's manual says range is "up to 5 m" (page 14).

Jay777

PM sent

Jay777

For those that asked...I did a quick range test for the other 3 bearings by slowing walking away from the car and noting the point at which the car stopped responding to the FOB (by observing directional light flashes and audible sounds of the locks). Results:

Driver side: 49ft
Front: 58 ft
Passenger side: 65 ft

So yesterday's test from the rear was not a fluke. One FOB got slightly better range than the other which is to be expected, and I did notice a slight reduction in range after 10 or 20 quick actuations at each bearing (possibly due to a temporary drawdown of the FOB battery. The test was done at 25 Deg F.
I don’t have equivalent “before” tests but as mentioned, I remember having to get with 3-5 ft for the FOB to work prior to the cap fix.

Looking forward to others giving this a try.

pp000830

Did you check your fobs to see if they swapped out the guts for their new aftermarket offering? Seems implausible that changing out a couple of caps would increase the range that much to something beyond what the remotes were capable of when new.
Andy

Jay777

Jay777

Below are pics of the immobilizer taken after the caps were swapped out. I can’t say for certain what was in there originally but the larger cap is 330uF, 10V and the smaller one is 0.47uF, 50 V (and they work). Extrapolating dimensions from the pics, they look to be standard Nichicon 10 and 5 mm diameters, both of which have standard 5mm lead spacing. For anyone wanting to give this a try, candidate drop-in replacement parts are:

330uF/10V: Digikey PN 493-13140 (Nichicon UBW1A331MPD1TD). Single piece price: $1.14.

0.47uF/50V: Digikey PN 493-11444-1 (Nichicon URZ1HR47MDD1TD). Single piece price: $0.37

You can buy online here. If there’s enough interest, I can add a batch to my next order and distribute.

Jay777

I followed up with ECU Docs yesterday to see if there was anything else they might have done to explain the 12x improvement in FOB range I’m getting. They confirmed what the repair report said, that all they did was change the 2 caps, adding “everyone should do this”. (They didn't respond to a follow-up question as to whether they would guarantee a range increase to anyone who had the mod done).

The pic below shows the radio portion of the board and the 2 caps that were replaced. (The PCB antenna can be seen in the upper left). The 0.47uF cap is clearly part of the radio circuit. It’s unclear whether the 330 uF cap is. It’s still a surprise to me that new caps could account for such a large improvement in performance, but there’s another possible explaination.... Repair shops would typically wash PCBs with a good quality flux remover/board cleaner after soldering and it’s possible the cleaning removed contamination that had accumulated over the years and degraded range down to 3-5 ft. If the cause is bad caps, contamination, or a combination of both, it means new 993s should have all started out life with 60 ft+ FOB range. Maybe there’s an original owner out there that can comment. Until then, we’ll have to wait for someone else to give this a try.

FYI, both my FOBs are the type shown below (P/N 993-618-259-02). ECU Docs made no changes to the FOBs, other than program them.

pp000830

Other than a slightly different production board and a lot of lint it looks like your remote is definitely the same as mine OE.