Many have probably heard about the problems with BCM (dx23-14B476-ae, dx23-14B476-ag, dx23-14B476-bg and the others) in facelift XF's. Perhaps due to a voltage drop, maybe because of covid-19 or magnetic storms on Mars ... the reasons are not fully clear) the memory of BCM turns into a mess.
The unlucky owner of the jaguar will find out that everything is bad with BCM when he disconnects a battery terminal. A sign that the module has already fallen into a coma is also the absence of a vin number in it and an error u3002-81 about a vin mismatch, which can be seen during diagnostics.
What to do?! The dealer in this case will replace both BCM modules (front and rear) and kvm module to addition. Professionals are limited only to the front. Both those and others unanimously assure that the module is not repairable.
In addition to the obvious problems with elementary flooding of these modules, both of them suffer from such an unpleasant amnesia with damage to the contents of the processor's internal memory (mc9s12xet256 stands in both BCM front and rear). This happens when there is a problem with the power supply. Moreover, as it turned out, for this is not even necessary to remove the terminal. Memory can fly off simply with a strong battery discharge or when editing the configuration. The whole tragedy of the situation is that both of these modules control almost all onboard electrics and are part of the car immobilizer system. The most common malfunction is the windshield washer or central locking stops working. The most unpleasant malfunction is “loosing the key” and the inability to start the car. Why is "loss of key" in quotes? Yes, because the keys are not lost anywhere, they are stored quietly in the KVM keyless entry unit (you can verify that they are working by pressing the headlights on button on the key). Accordingly, there is no point in rewriting the keys in this situation. It happens that the ignition turns on, but there is no start, for example, due to the fact that the body does not supply power to the ABS unit. Or some other module. What to do? Two options are possible here: if the memory is not critically damaged (only the central lock does not work), then the car can be completely fixed using SDD (and only SDD!). If the memory is significantly damaged (in the BCM module idents there is porridge instead of wine, the windshield washer does not work, error u3002-81 hangs about the mismatch of vin, the red inscription "electric key not found see manual" is on the panel) - no way without surgical intervention. The module must be removed, disassembled and the firmware restored using an external programmer. The scale of the disaster varies. Sometimes the contents of the module turn into a solid mess - in any case, there is a solution and there is no point in buying a new BCM. Since not everyone has a programmer, I stocked up on a few of the most popular BCM's and am ready to send them to you in exchange for your faulty ones. Please note that these modules also need to be programmed using sdd!
To summarize: if you have an XF facelift (it doesn’t matter, 2012 with a key slot or newer, without a slot), then sooner or later you are doomed - your unit will most likely not survive a strong voltage drop or disconnection of the battery terminals.
Maybe the car won't start at all. Perhaps only the central locking will fall off. By the way, about the central lock. This is probably the easiest malfunction with BCM: just after disconnecting the battery, the car stops locking the doors. At the same time, it reacts to the key, makes a beep-beep when trying to close the car with the key and clicks the gas tank hatch. The doors, however, remain unlocked. There is also no reaction to the "open / close" buttons on the dashboard. It is repaired quickly, again with the help of SDD.
Personally, I have never come across prefacelift with damaged BCM. And the processor in them is different, with a different memory architecture.
How to protect yourself? Monitor the condition of the battery, do not let it discharge (this is probably the main rule), do not disconnect battery terminals. For now, this is the only solution. The problem is in the design of the processor itself installed in the module. And this, glitch, cannot be fixed by firmware update or recall. If, despite all of the above, you still want to remove the terminal from the battery or think that your 10-year-old battery will last another winter, then keep a computer with the SDD program and the appropriate adapter on hand so that your carriage does not turn into a pumpkin at the most inopportune moment. Well, if this still happened - Contact us
