P38A Losing codes if battery goes flat

This site contains affiliate links for which LandyZone may be compensated if you make a purchase.
When you consider the price of going to a garage for a diagnostic report, it doesn't take many trips before things add up. Once you have it, you'll not look back. It's a great thing to have
 
I can't work out if the original question got answered or not, but yes, if the battery goes flat while connected then it can:
i. desynch the key (especially if the remote button was pressed with the car battery disconnected/flat) it's usually simple to resynch if the key fob is not damaged, and the drivers door lock is fully functioning, although you need to clear any immobilisation first. You are most likely stuffed if the BeCM has been changed and not programmed properly since it contains lockset coding
ii. the engine will most likely be immobilised. It may be remobilised by putting the key in the ignition (if the induction coil works still it will trigger the fob to disarm the immobiliser). Or it may need the EKA - this can be input via the door lock (though you are probably stuffed if the BeCM has been changed - it contains the EKA). LR will give you the EKA from the original BeCM FoC - which will only help if it was reprogrammed properly
iii. BeCM to Thor coding - above my pay-grade as I have the earlier GEMS, which will automatically relearn the code when the diagnostics is used. I am told that with Thor you will have to go into the ECM pick up the code, and then type it back into the BeCM, but that's second hand info.

If Thor cranks but doesn't fire then iii. is a distinct possibility and depending on what diagnostics the garage has they may/ may not be able to fix it.

If the battery was disconnected "properly" ie unlock, pop the hood, undo the negative. then more than likely nothing loses synch (never has on my GEMS, at least)

Did they really change the BeCM? If they had I wd have thought you'd have even more problems than this, unless it was coded properly. I'd be asking for the original BeCM back i. as proof they changed it, but ii. because you're probably better off reverting to the original one. If the power board in the original BeCM was playing up it can be swapped with another BeCM of the same vintage without recoding the BeCM.

Who are these jokers?
 
Last edited:
Thanks Marjon,
That's what the garage was saying that they needed the diagnostics, but what I did suspect was the fact that they would need to input all the codes again if the battery went flat(presumably if the battery was disconnected as well). I found it interesting that you mentioned some owners buy their own diagnostics. If you have that and find out what's wrong would it still have to go to the garage to be fixed?

If you plan on keeping the car diagnostics is a good investment, end of story. Especially if you can do a bit of spanner work, it would not need to go to the garage. Remember it covers a lot more than just BECM.
Now to buy diagnostics personally todo the level of work “your garage” has claimed is very expensive. I would think highly unlikely your garage have that level of diagnostics.
It’s more likely they sent yours off and either had it repaired or info put on a secondhand 1. How much did they charge for the BECM itself not including labour?
There are a few cases where your £400 (+/- cost) diagnostics will not be able to help, and you will have to seek professional help, but as I said earlier a well kept car, good personal diagnostics is a good tool for the toolbox. There is also a very strong second hand market for resale.

Now you may scan this forum and say well there are so manyBECM problems, I am afraid that is the nature of forums mostly fixing problems. The biggest majority on here don’t have BECM problems.

in short.
Don’t worry about a flat battery if the rest is good and diagnostics is a good investment. Enjoy the bloody thing:)

J
 
Thanks.
It's not the radio code or use of the emergency access code. The garage has to reset the vehicle codes with (presumably) a diagnostics kit and they said that if the battery goes totally flat the codes may have to be reset!. It does sound a bit far fetched to me but that is what I have been told. The battery was fine when the car wouldn't start (the engine kept turning over but wouldn't fire - the BECM had previously been replaced) but because it took 8 months for the garage to get its diagnostic tool back (a long story) the battery would have been completely flat.

In short, almost certainly no.

Most of the time no codes needed at all. Procedure to sync the fobs is in the manual and just requires turning the key and pressing the fob button. Occasionally the EKA code needs entering using the key. Very rarely the EMS code goes out of sync but usually after RF interference or some weird set of circumstances. Diag is needed for that.
 
Hopefully it's a misunderstanding between yourself and the garage, they aren't taking the preverbial and you haven't mistaken what they've said. It is amazing how many clients can agree and understand what your saying on the day and then completely forget or even deny anything you've explained.. Not all but....
 
Thanks all again,
I was told that the BeCM had been replaced , the part cost £450 and was guaranteed for 2 years. I was also told that if the battery goes flat when in the car It "might" need the codes reinputting. Nothing to do with the radio, key fob or EKA. The garage is a so called specialist on Land Rovers. The story they gave me for having to wait 8 months was that Autologic had taken their old diagnostics (that had P38 codes) and given them a new one that didn't include the P38. They eventually had to borrow kit from another garage as they didn't want to spend what Autologic wanted for replacement. I like the idea of a solar panel charger. Any recommendations. I also like the thought of my own diagnostics but worry I would still need to involve a garage(but a different one!)
I think the P38 is brilliant and would love to keep it but it will have to be more reliable(wife would get rid). Apparently computer routers can affect the battery.
 
Thanks all again,
I was told that the BeCM had been replaced , the part cost £450 and was guaranteed for 2 years. I was also told that if the battery goes flat when in the car It "might" need the codes reinputting. Nothing to do with the radio, key fob or EKA. The garage is a so called specialist on Land Rovers. The story they gave me for having to wait 8 months was that Autologic had taken their old diagnostics (that had P38 codes) and given them a new one that didn't include the P38. They eventually had to borrow kit from another garage as they didn't want to spend what Autologic wanted for replacement. I like the idea of a solar panel charger. Any recommendations. I also like the thought of my own diagnostics but worry I would still need to involve a garage(but a different one!)
I think the P38 is brilliant and would love to keep it but it will have to be more reliable(wife would get rid). Apparently computer routers can affect the battery.
Your RF receiver can pick up spurious signals from WiFi,wireless door chimes,weather stations etc.there was a case of a cafe in Bowness affecting parked cars because the waitress was using a wireless order module that transmitted to the kitchen.these signals wake up the becm and it thinks its being stolen so relocks the car. This can happen regularly and lead to burnt out locks and a flat battery. I had my car disabled in Carlisle once because of a department stores WiFi. There are many sites around the country known to the breakdown services where cars were disabled until towed away from the area.
 
I was also told that if the battery goes flat when in the car It "might" need the codes reinputting.

Rubbish don’t worry.

The story they gave me for having to wait 8 months was that Autologic had taken their old diagnostics (that had P38 codes) and given them a new one that didn't include the P38.

Did I not say they wouldn’t have paid for it;) and as far as I know Auto logic cannot reprogram a secondhand BECM. Which is what you got. Ask them for the EKA code.

As for all the extra WiFi squiggly things flying around, yes it seems too be a problem and is all to do with the RF receiver frequency. For right now the best course of action seems to be to unplug the antenna to said unit. You just need to be very close to the car to unlock.
There are fixes for this but don’t worry about them right now:). Same with charging depending on where you park the car and how often you use it.
Search on here for diagnostics there has been many discussions about it.

Take the good wife out and float her about in a great car she will soon love it. Some say “oh it’s too big”:eek: My M wouldn’t drive anything she doesn’t feel safe inside:).

J
 
Rubbish don’t worry.



Did I not say they wouldn’t have paid for it;) and as far as I know Auto logic cannot reprogram a secondhand BECM. Which is what you got. Ask them for the EKA code.

As for all the extra WiFi squiggly things flying around, yes it seems too be a problem and is all to do with the RF receiver frequency. For right now the best course of action seems to be to unplug the antenna to said unit. You just need to be very close to the car to unlock.
There are fixes for this but don’t worry about them right now:). Same with charging depending on where you park the car and how often you use it.
Search on here for diagnostics there has been many discussions about it.

Take the good wife out and float her about in a great car she will soon love it. Some say “oh it’s too big”:eek: My M wouldn’t drive anything she doesn’t feel safe inside:).

J
To unplug the antenna remove the drivers side parcel shelf support panel,three plastic clips and one Phillips screw.You will see the rf receiver by the rear seat release button.unplug the blue wire.job done.And you cannot use the weather as an excuse not to do it,you can sit in the boot all cosy..when the clips and screw are removed it lifts upwards out of three spring clips by the window.
 
Last edited:
To unplug the antenna remove the drivers side parcel shelf support panel,three plastic clips and one Phillips screw.You will see the rf receiver by the rear seat release button.unplug the blue wire.job done.And you cannot use the weather as an excuse not to do it,you can sit in the boot all cosy..when the clips and screw are removed it lifts upwards out of three spring clips by the window.

Looks like your memory's getting better:)
keep up the good work.
 
Looks like your memory's getting better:)
keep up the good work.
You may be right Brian, how's things with you? I had a telephone consultation on Wednesday and the specialist said I need a CT scan,just had a phone call from the hospital asking could i make it Sunday and what time would be best for me.:D Thought I would be waiting for months.
 
Thanks all again,
I was told that the BeCM had been replaced , the part cost £450 and was guaranteed for 2 years. I was also told that if the battery goes flat when in the car It "might" need the codes reinputting. Nothing to do with the radio, key fob or EKA. The garage is a so called specialist on Land Rovers. The story they gave me for having to wait 8 months was that Autologic had taken their old diagnostics (that had P38 codes) and given them a new one that didn't include the P38. They eventually had to borrow kit from another garage as they didn't want to spend what Autologic wanted for replacement. I like the idea of a solar panel charger. Any recommendations. I also like the thought of my own diagnostics but worry I would still need to involve a garage(but a different one!)
I think the P38 is brilliant and would love to keep it but it will have to be more reliable(wife would get rid). Apparently computer routers can affect the battery.

Don't think Autologic will touch BECM. Testbook would or Nanocom for some stuff but other than that you're looking at a Faultmate.
 
You may be right Brian, how's things with you? I had a telephone consultation on Wednesday and the specialist said I need a CT scan,just had a phone call from the hospital asking could i make it Sunday and what time would be best for me.:D Thought I would be waiting for months.

I am ok thanks but have been told by letter that I am to stay at home again as clinically extremely vonerable to this virus, great being self employed :(

Glid you seam to be getting back to your old self:)
 
Good luck mate,it cannot last forever, ...can it ?:(

I think by the time Easter next year has passed we'll be on top of it and seriously winning. Couple of wobbles over the winter, a bit of time to get the Oxford vaccine out and get cases down and by May we'll be looking forward to an ice-cream summer.
 
I think by the time Easter next year has passed we'll be on top of it and seriously winning. Couple of wobbles over the winter, a bit of time to get the Oxford vaccine out and get cases down and by May we'll be looking forward to an ice-cream summer.
Hope your right mate, should have locked the country down completely in February and it would all a memory now,but hindsight is a wonderful thing.:)
 
Last edited:
Back
Top