Ok, so a week or two ago I had a problem with the Immobilizer. I turned the key to crank and got nothing, only a "Immobilzer - see manual" message. Well, the problem was the battery. The battery was completely drained. Couldn't even use the central locking system to get into the car and had to use the pos. thing under the hood to give it a jump (car wouldn't start but the locks worked). We replaced the battery and it ran perfect. Fast forward to today; I go out to start it and no crank. Great..... the Immobilizer message comes up again too. Arg! I had my alternator and alternator belt checked out and both were fine. I'm assuming this is due to my battery again? What could be doing this?

 

Something may be staying powered up killing the battery.

 

I thought so too. Battery was at 50% last night - brand new battery that was bought 1 1/2 weeks before. I charged it and drove it to my local mechanic (about 1 mile away). They checked everything out and nothing. Everything appeared normal.

So I go to the shop to pick it up (they did the work free of charge because it was basically what they had done a couple weeks ago) and whadda ya know it wouldn't start! Right there in the shop parking lot. This was after hours after the mechanics went home, but the receptionist (who also knows quite a bit about cars) came out and saw what i was talking about first hand and is also puzzled. So I'm thinking maybe it is the Immobilizer as the battery should still be at a full charge and it gave us the Immobilizer message tonight at the shop. I'm not sure though, because if it was the Immobilizer why did a battery recharge fix the problem in the past?

 

I had a problem very much like this in a Mercedes I used to have, the battery would occasionally be dead, it would always jumpstart and charge back up completely when running, Iwas never able to find any unexplained current drains. One day I noticed that the electric fan was siezed and I figured out what the problem was, the fan was being switched on sometimes before the car was switched off and by design it would stay on, unfortunately my fan was not working and was just a near short circuit of a load that would drain the battery quite quickly, but after things cooled down the load would go away which is why I had not been able find it, I am not sure how the Volvo fans are wired but it might be worth checking...

 

My mechanic is really lost on what the issue is. Whatever it is, it's intermittent.

They've condcluded that it's not a power issue (battery,etc). The Immobilizer antenna is functioning properly and that there is no unusual draw on the battery (shut down is 50 milliamps with a 4 amp draw for 2 minutes.

They're thinking it's an electrical problem or something to do with the anti-theft system. Are there any common issues with the anti-theft system?

 

Also, when Immobilizer antennas go out, can they go out slowly and sometimes work/sometimes not? When they tested the Immobilizer, the car was starting properly. They haven't got it to not start again, so they haven't been able to test the antenna when it isn't starting. Maybe the Immobilizer antenna is slowly starting to fail? Any imput?

 

Usually if the ring goes bad when it does not start you can remove the key and flip it 180 and make it start.

 

also, just a thought. make sure your cabin blower motor shuts off once you take the key out of the ignition. if it keeps running all night, even at a low speed, it will drain your battery by the next morning

 

They checked the cabin blower motor. It does run when I open the door without the key in the ignition and they shop said it runs for about 2 minutes after the car is shut off. Is this normal? If not, how can I fix it?

 

I realize it's been a while since your post, but did you ever get this issue resolved? If so may I ask how? I just purchased an S60R about a month ago and in the last couple of days I have experience the EXACT same thing. It appeared my battery was dead, was jumped started, went to dealership and got a new battery installed as well as had a complete inspection...appeared all was good got it home, the next morning...it won't even crank. Everything else seems to work fine, AC, radio, lights, etc. I have replaced the starter relay and the antenna ring...no change. It will start and seem to be fine but if I shut it off, no start. Very intermittent! It's been at the dealership now a day and they are baffled. Any info you can share would be greatly appreciated!

 

Have you tried the starter plug. This same thing happened to me, but it cranked each time and started the third time I tried. It blinked the immobalizer message once, but I think that was just a warning that the car was low on battery.

The other advice I found in other locations was to change the fob battery and then try flipping the key 180 degrees.

 

our fan blower is staying on our volvo s80 also ? draining the battery what do we do ?

 

if the fan stays on, i think you can pull the fuse to save your battery.If that works, there may be an electrical problem with the fan.

 

I know its an old thread but did u fix the problem.. if so please advise... thank you