Automatic stalling?

[RevDave]

Hey guys,

Just bought a 2010 Mercedes CLC220 CDi Sport and wanted to pick someone's brains who knows more about these cars than I do (first time owing a german car). I was in a car park yesterday reversing out of a space when suddenly without warning the engine just cut out. No warning lights, beeps or anything. I put the car back into park and turned key off completely and back on, engine didn't even attempt to turn over. After 2-3 attempts the car started and immediately stopped. I pulled key out waited a few seconds and she started up and havent had another issue since.

What could have caused this to happen?

On a separate note, when looking for upgrades etc I keep seeing these W numbers. What number should I be looking for when looking for aftermarket parts?

 

[Bert_W164]

Hi Dave,

it's difficult to tell without some diagnostics. Could be a sensor playing up, could be a faulty alternator not giving enough charge, could be a dodgy earth point and so on.

Best thing would be to find someone with a Star diagnostics kit to see what's going on, cheap code readers will read engine codes, but not much else.

 

[Stocious]

Keep reversing like you did and try to get it to happen again, bringing it to a garage and asking them to fix a fault that isn’t there or dosnt surface while they have it is a pointless venture, one thing to check off the top of my head is do you have bad engine mounts, check and tell us

 

[RevDave]

Hi guys, Have had this a few more times since. Go to start car and it doesn’t click or anything just sits there with dash lights on. After a Few attempts of putting key out n back in she fires up and all is good.

 

[MJJ]

Not sure if your CLC is the same as my equivalent era E, but on mine, the car deliberately disables the starter motor if the battery voltage is below 12.0V. You get all the dash lights, but no starter, no click, nothing else.

On mine, one approach is to turn the key to ignition position 2 (all dash lights, and glowplugs warming), leave it at position 2 for 10 seconds or so before turning to position 3 and trying to start. This 10 seconds pause allows the battery a little time to recover voltage back over 12.0V after warming the glowplugs.

This is a 'cheat' though, it is defeating a failure somewhere in the charging system - alternator or battery. You really need to find a way to check the voltage of your battery, via a voltmeter or take it to Halfords etc. for a battery test.

Many automatic cars have a starter inhibit on the gearbox position too. The starter only turns when the car knows it is in P or N. Assuming your car has a gear selection indicator on the dash, double check the car knows it is in P/N when the car fails to crank.

The stalling/cutting out would likely be a different fault in my opinion. A failed alternator may cause an engine cut when the battery runs out of power, but I cannot imagine the car would ever restart if this were the case. To cut suddenly and at idle, my guess would be crank position sensor but diagnostics will help you track it down.

Martin.