Does not start

Please provide more information.

"I put the key in the ignition, turn it and the warning light goes out, I turn the key to start but there is nothing..." or

"I put the key in the ignition, turn it and the warning light goes out, I turn the key to start but there only a ticking/clicking sound..." or

"I put the key in the ignition, turn it and the warning light goes out, I turn the key to start but the engine only turns over and doesn't catch."

Most likely, the problem you are dealing with is a dead battery. The reason this is apparent is you said "there is no clicking noise like a bad starter, it just does nothing..." Normally, if there is any charge at all in the battery, you will get the clicking noise you describe as the ignition circuit is trying to charge the solenoid that turns over the starter and turns on the engine. If you have a battery jumper box available, your S40 will probably start at the first flick of you ignition key if your battery is fairly new. To hook up the battery box, just place the clips as you would standard jumper cables, red to red (+) on the battery and black (-) to a good ground point on the engine (it has to be solid metal-to-metal contact). Then turn key to fire up the engine. Once your car has started you have to run it about 10 miles to put any sort of charge back into the battery. If the battery won't hold the charge then it is time to replace it.

Without hearing it very hard to say.It actually just sounds like a bad battery & alarm,fuel pump,some relay is just not getting full power-Start with having battery tested-JT & Good Luck

Does it do anything when you try to start it? Like make any noise? if so what does it sound like? TICK TICK TICK? Or will the keys even go in the ignition? Will the keys turn or not at all?

if an ignition switch fails, sometimes you can jiggle the key and it will start right up. its very hard to tell. but if you can start it by bypassing the ignition switch, then its the switch itself. go to this site for more detailed info--- aa1car.com/library/1999/cm119948.htm---this page should help. click on top link.

CHECK IF TURN SIGNALS WORK, USUALLY ON GM CARS IF A BULB IS BURNED IT WILL TICK FASTER, IT IS AN INDUCATION OF BURNT BULB - COULD BE FRONT OR REAR

Immobilizer armed its self

You either have a bad solenoid on your starter OR a bad ignition switch as these are the only two things that can cause the symptom you describe... I lean to the solenoid first, RARELY does an ignition switch sieze up in the start position but it is a possibility. Several national chain parts stores can test the starter for you (GM starters have the starter solenoid mounted directly to the starter and you need to remove the starter to get to it, so you would take the whole unit in to test it... REMEMBER to disconnect the battery first!)

It could be the park/neutral switch, next time it doesn't start try wiggling the shifter in park while turning the key, or shift to neutral and see if that will work. if that doesn't change the problem I would replace the ignition switch.

solenoids are worn out, it will probably eventually start after 4 or 5 clicks but its annoying as hell