ok, what is it and what does it cost?

Got a slow drain on the battery that might involve replacing this part. Thoughts?

 

Check that the tiny door in the front of the ignition key slot is not sticking open. This often prevents several computer modules from going to sleep.

The BCM is a computer module that control dozens of different functions. If you really need to replace it, get a used one with a matching part number and VCATs code, but a lot of things besides the BCM can cause a battery drain.

 

. . . lots and lots of things.

The security system at the top of the list. The 'sleep' mode battery drain should be less than 30ma. The sleep mode should occur 2 - 3 minutes after everything is shut down . . . with the key removed. Still have more drain . . . lock the car which should immediately put it into sleep mode.

 

Grab JTIS and it has more info including electrical guide.

 

Thanks - I tried leaving it locked for over five days and it still died. Did not notice the 'little door' by the ignition switch but will inspect that next.

 

Check for drain by putting your voltmeter turned to amps between the battery and the battery cable positive. Pull out the trunk light bulb and then watch the meter. The drain should be less than 50 milliamps with nothing running. If you have more, start pulling fuses until the rate drops to less than 50 ma. The last circuit you pulled has the drain.

 

Hey, thanks for that - going to send that tip over to the shop since they still have it. ...then again, if they don't know this by now, I need to find a different shop!

 

I just got the estimate from the shop. They've disconnected everything possible and narrowed it down to the body control module itself. Diagnostically I'm already up to over $600 in time spent to do this - I saw what went into that and I don't doubt it was a lot of work.

To complete the job will set it up to over $2k! If I'm reading their estimate right, the BCM itself costs about $1100.

The only problem I'm experiencing with this car is a battery that dies if left unattended for a few days. Trying to decide if that's worth the trouble to replace the BCM and if there are any other reasons to do so aside from fixing this one annoyance. If the BCM is bad in this sense, could it be bad in other ways that may manifest themselves later?

 

check around - BCM can be found for about 800 if not less - call Terry's Jaguar parts or check SNG Barratt (sponsor) - SNG shows one for $665 then would need programmed. Trust me - shop around - had my local dealer (before I found the forum) try to tell me I needed the BPM - $1200 for the part plus 550 labor. Did find it cheaper but luckily I ended up having an issue that was other than the BPM

 

Thanks, I will do just that. SNG Barrett is right down the street from me in Manchester NH. So you think it's worth replacing?

 

You could just disconnect the battery on one terminal when you know you are not going to use it for a few days. Taking into account insurance issues of course, it could buy you time until an affordable BCM becomes available. Are there no refurb services available for this part in the U.S? I know there are some places recommended on this site which refurb some of the modules, but not sure about this one. Its usually a bad connection or a failed diode/resister, after all they are getting a bit long in the tooth now and part are due to fail because of old age.......

 

Just tried Tom's but they don't have the exact part and VIN number is critical with these, as one would expect. Yes, I could wait till one comes available but it's a lot of labor to get this far so might as well get the job done.

After talking to SNG, their price is about what the shop is charging, slightly more ($1500). They say the units need to be exact for the car and an unprogrammed unit would need to have the latest/correct software from the Jaguar dealer, which is why they're expensive. They don't even take these things as cores, they just toss the old ones. So though I might be able to find the fault with the old unit, it's not clear that anyone refurbs them or does so correctly.

I'm not keen on installing a used one that might work only to have it mess up something else electrical. Has anyone tried a swap here?