So what makes it go out of sync?
I had heard similar IrishRover, and that does make sense, but then you hear a lot that you don't actually like to state as catagorically correct.
:behindsofa:
My mate ended up fitting the logic board from the old BeCM he had kept with the power board from the supposedly newer replacement for this customer. But i have absolutely no doubt that he is simply buying time for the customer.
This is borne out by the fact that we now have almost 2 dozen indies who buy these from us at ten a time to get the maximum 22.5% bulk buy discount and then supply them as part of the fix cost to their customers. This also happens with our kicker lites where they have a P38 owner with a repetative and problematic EAS that is uneconomical or otherwise proving impossible to permanently fix.
I guess adding an extra 50 quid into the bill and knowing that your customer has a workable solution that any idiot can use is much better than an angry, left in the lurch with a recovery fee one blaming them for having thought they fixed it.
Canyon:
The jury is still out on what exactly causes this well known problem. Some think it is down to RF interference and some think it's a low battery voltage thing.
I have collated enough reports to support both theories equally and have a few more.
Interestingly i happen to have over 25 years experience with EEPROM technology, i know it like the back of my hand and when you really think about it, absolutely everything i have ever done and still do is based upon it in some way or other.
Not surprisingly, and probably quite sadly, i happen have knowledge of it down to the micron level.
EEPROM wear out is by no means new, i first encountered it myself 20 plus years back in Renault / Phillips 661 and other model car radios when i used to run a car radio repair business.
The strategy was that whenever the Radio was powered down, Ie when the IGN was turned off, it would store the current volume level and selected frequency in its serial EEPROM, such that on re powering it could put the volume back to how it was and tune into the same station it was on etc.
However the problem was that the EEPROM was not storing the right values and users would find the volume way too loud or too quiet and that the station was just mush when they came back to their cars and turned the ign on.
Like mobile phone batteries, EEPROMS can only have their cells charged a finite number of times before they don't store a charge any more. And in binary, something that should read as a 1 (Charged) reading as a 0 (discharged or Fhooked) can make all the difference in calculating a number from it.
This aspect of EEPROMS is known as EEPROM endurance (defined as its maximum number of erase / write cycles) and if you google it, you will see what a big problem it really is.
I have personally encountered well over 100 examples of techniques being employed in the utilisation of EEPROMS for storage in such a way that is designed specifically to try and avoid this. I have also encountered a number of cases where a failure to impliment some kind of plan has resulted in common problems like the radio example.
A common way is to store something in 10 places, read them all and compare, if one or two are different to the rest, those are re written back to the same values as the rest.
Even if the design is such that the cells are not constantly being re charged, thus wearing them out prematurely by virtue of the Erase / write cycle, EEPROMS have a data retention period not guaranteed to exceed 10 years at best. And how old is your P38 !!!!
However my educated guess for what it is worth to ya, is that the sync code in the BeCM is being re written periodically, causing premature cell wear out, which is why other data in the BeCM's 640 byte EEPROM is not being affected.
I have decoded some read examples of the sync code the BeCM supplies after forgetting what it should really be ssupplying and have noted that the difference is indeed the BeCM EEPROM supplying zeros where it should be supplying ones.
I apologize to anyone still awake for all the techno mumbo jumbo detail.
The bottom line is that if you have a P38, at some point it will not start, and it will require a BeCM to EMS re sync. After then it will likely need the same done periodically.
At present the most convenient and affordable long term solution is to get a Sync Mate and keep it in the glove box.
No..there is not a backup battery fitted. Not needed.
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