So my check engine light came on a week ago and I got the code ran , some sensor that reads coolant temp, car runs fine and not hot or cold, so I told the mechanic I'd be back when I had the $200 to drop on it. Tonight when I went to run the car the immobilizer light came on, the car ran fine, but light is still on... this is the first time I've had the car in mid 20 degree weather though... any ideas why it's on? Seems like yet another thing I will need to sink money on.

 

I have never seen that before.

 

Well that worries me Tech!... Today I left the car in the garage all day, took it out tonight to head to work and no immobilizer light... Makes me wonder if my battery is going dead...maybe the two are connected?... I'll put in a fresh battery this week and go from there...

 

That sounds like a plan.

 

What hepend whit your light?
I have the same problem, 2003 S40 immobilizer light is on and the car runs well ?!?!?!??!? My battery seams ok. Any opinions?

 

sorry for not updating, changed the battery (which it needed anyways) but no luck, immobilizer is still when it's mid 20's out. But, I am going to go ahead and work on changing the thermostat and coolannt sensor this weekend and see if that has something to do with it. I will update accordingly.
Another question, anyone know if i fix the reason the check enine light is on,will it clear itself?

 

No you will need to get the codes cleared.

 

My 03 S40 has the same immobilizer issue. It went away for a while but recently came back as temps hit 20-30 degrees at night (NJ). I just end up restarting a few times, running it a little longer and eventually it goes away. Occasionally I get traction control light as well. Never stops me, just annoying.

 

Same problem except the car wouldn't start at all and immobilizer light flashed on ignition.
Stealership replaced antenna ring (mucho dolores$$$) and the battery because the battery failed the load test?! Also radiator hose leaking that time too! All in all $600. They charged me $50 for battery installation! Thats like a half hour labor, it takes 5 minutes!

 

I'm a stubborn one, I refuse to hit the dealership...find a good foreign car expert in the area, your sure to save some dough Lyons