HELP! '11 MCS won't start!
 

So my 2011 MCS decided to not start today. I can unlock and lock the car with they hey, the interior lights turn on, but when I plug the key into the slot it doesn't go on accessory mode and pressing the clutch and start button does nothing. Like literally nothing, no clicks no hums no noises. Like my battery is dead but it isn't (I have 12V on my multimeter and like I said, my lights go on). I even tried jumping it off my dad's car with no results. Funny enough it turned on and did a 60 mile trip this morning, then later in the day it just died.

Is the CEL on? How old is the battery? Have you ever had it replaced? A normal battery should read a voltage slightly above 12 volts with the car sitting still, and no electrical devices on. A typical reading would be in the 12.6-volt range when the battery is fully charged. If the reading is 12 volts or less, then the battery needs charging or needs to be replaced with a new one.

Is its a manual ? Did you check the clutch pedal sensor , but if you dont have the light come on when you put it in the slot and press in to kick , it might be the key fob recepitcile.

Key fob reader 61359299332

https://www.ecstuning.com/Search/Sit...h/61359299332/

https://c1552172.ssl.cf0.rackcdn.com/873326_x800.webp



Try its again, and press the key fob all the way in on the start stop switch.

Check the clutch safety switch under the dash, many people kick them off, and you can usually just snap them back in.

Not many people have trouble with the keys or ignition unless you have crammed the key into the ignition one two many times, chances are it is something to do with the safety switch. Even with a dying battery you should still be able to hear the starter solenoid click, if you aren't getting that then there is a starter lock situation that you aren't disabling, ie safety switch or EWS problem (which would give you a light with codes).

Checked all of it. Yes, the CEL is on but I know for a fact that it's a leftover misfire code. I can't even get my car into accessory mode anyway. I brought it to my mechanic today and he says I probably need a new key fob. And if that doesn't work it's the key slot. I just wanted to now if anyone here had the issue and I didn't somehow melt my ECU or something.

I have heard a couple bad key fob start stop slots. Most of the time its the trigger in that the when you push the key fob into the slot it will not side forward or lock. Which on a non CA car it will not start.

Might be easier to do that first, then replace the key fob.

New Battery
 

This just happened to me in my 2011. Very similar issues. I needed a new battery and that solved it all.

Turns out my key fob died. Got a new one and a spare at the cost of $600 total (with a tow to my shop and labor).

Thanks for the update.