Advise on BECM issue

This site contains affiliate links for which LandyZone may be compensated if you make a purchase.
B

barmybilly

New Member
Posts
4
Hi all, I have a 97 4.6 hse and I am experiencing a few problems and after some advice.

It started when both front locks failed over the space of a month. Tracked it down to the small electic motors in each lock and replaced them, these lasted for about a week and they burnt out again, the alarm was coming on at night and draining the battery in the morning, and ocasionally I would come down to the car to find that the drivers door window had dropped (come down about 1 inch).
I changed to the latest receiver and the alarm has not come on nor has the battery drained down so that seems to have fixed that problem.
Then the sun roof stopped working and the message has come up that the market is not set.

Having read through the various posts re the BECM, I am thinking that mine is now on its last legs and will need to go for repair.

I would welcome any comments on my rangies symptoms and whether you feel my deduction re the BECM is correct.

cheers:confused:
 
:welcome2:
Hello and welcome.
It would seem you're correct but make absolutely sure your battery is in good order. Bad batteries play havoc with BeCMs. Also check the connectors if you haven't done already. If all else fails though, you may have to send it off to someone like Irishrover or Rick The Pick for diagnosis and repair. Good luck.
 
Becm's do weaken over time. They're are constantly powered even with ignition off. They go to sleep & wake up when needed & keeping in mind that the components used have a ten year life. The memory's also weaken & they start to forget things like the sunroof & display messages in another language. Other times they just give up & illuminate the indicators to flatten your battery.
By replacing some weak parts & reflashing can bring them back to life.
 
thanks rick the pick, at the moment my lovely car is having a recon lump dropped into it and i think i have spoken to you via ebay this week or at least someone from callrova. the BECM is going to be shortly coming your way whilst the vehicle is off the road.
thanks for the reply.
 
Rick-the-Pick said:
Becm's do weaken over time. They're are constantly powered even with ignition off. They go to sleep & wake up when needed & keeping in mind that the components used have a ten year life. The memory's also weaken & they start to forget things like the sunroof & display messages in another language. Other times they just give up & illuminate the indicators to flatten your battery.
By replacing some weak parts & reflashing can bring them back to life.
Click to expand...

Where does this crap come from about components having a ten year life? I used to manufacture controllers using many of the same semiconductor components, electrolytics etc. The first units went out in 1986 and apart from memory support batteries (flash was too expensive) they are still running. Failures are mostly due to outside events.
Flash memory is a different matter but again I know of very early examples of flash memory still working fine, just not in the noisy electrical environment of a car.
Semiconductors can and do fail at random, infant mortality used to be a common problem overcome by a burn in test, failures due to atmospheric conditions (lightning discharge) Alpha (or was it beta) particle strikes, inrush currents on turn on, overheating and over voltage are all causes of failures.
 
Datatek,
I purchase components from all over the globe. The ten year life span in clearly printed on the data sheets.
It just so happens that a hell of a lot of the early becms, & i have approx 1,000 of them, all major failures.
Becm's start to fail constantly around the 8 year mark. the parts that were manufactered around 1992/3 have completely given up & cannot be replaced due to obsolete parts.
You're correct in the lifespan being controlled from outside influence as we have seen some remarkable becms that were fitted to the early 1994 p38's & are still going strong.
I've also seen a hell of a lot of becm's from 2002 models that have expired.

All we do is becm's seven days a week, other than a few other ecu's as favours for the trade, & you're more than welcome to pay us a visit, sit in or as you have the knowledge, you could test & repair a few yourself, & then you will see exactly the crap i'm talking about.
 
I have most of the data sheets from TI, Motorola, Rockwell, etc, none of them mention a 10 year working life. EPROM's and certain memory chips are a different matter but the life is governed more by cycles than time. I have had no trouble sourcing parts to date except for an A to D converter and a temperature chip.
Electrolytics certainly have a defined life expectancy but failure is easy to spot and replacement presents no problem.

If all you do is BECM's 7 days a week, you must get through a hell of a lot of them, in fact you must by now have repaired more than there were P38's ever produced.

I still reckon most of the BECM failures are caused by external events.
 
We certainly have seen a few come through our workshop. We deal with Main Dealers, independents, & private owners, worldwide. We test, repair & rebuild & we have seen the same becm's more than once, although through no thought of our own. When these things fail it's 90% due to other factors.
These becm's would last many many years if they wasn't fitted to a car.
The Electrolytics are a problem, & the main cause in logic failure. the CLT's are the worst & can only be replaced by hand. Try soldering one of those to a class 3 standard, let alone pulling the failed.
 
You must log in or register to reply here.

Similar threads

I
P38 BeCM locked?
Replies
8
Views
896
pwood999
pwood999
A
P38A Cruise control question ( wheel speed issue )
Replies
16
Views
1K
AndyF07
A
P38 guy
P38A Aftermarket remote
Replies
1
Views
508
pwood999
pwood999
Jazydave
Blower fans
Replies
12
Views
463
Datatek
Datatek
Joss155
P38A 2.5 dse becm syncmate
Replies
17
Views
2K
Joss155
Joss155
Back
Top