Hi everyone I have a problem with my slk200 r171 2008. I've had the car 5 years and have had no problems - I love it! But this week the alarm system starting playing up. When locked the lights flashed as it would for the tow alarm then the siren would go off. When using the key fob to unlock the lights flashed correctly. But seconds later the siren would go off intermittently. I have read the MB forums and followed links regarding the PSE pump but we can't find it. My husband has taken all the relevant panels out of the boot where it could have been situated but no it's not there. We have had to take out the siren as it will not behave! Our question is does my model actually have a PSE pump or is it electronic? We are baffled. Thanks to anyone who can shine any light on this for me.