SMART FORFOUR. Well known starter motor fault.

Do not buy. Poor quality vehicles and Mercedes-Benz finance dont give a to§!! The starter motor fault on the forfour is a recognised fault and yet they are still pushing them on customers.

[minitune]

1. Smart Mechanic here, a very common fault is the main starter motor cable - the large red one, coming loose on its own. Even had it on my own smart Fortwo 453! Firstly disconnect the battery at the front of the car. Get a good long nose torch and locate the red cable on the starter motor it’s just under the manifold & dipstick right rear. If you can toggle the cable connector with your finger it needs tightening up. Nothing needs to be removed it’s a size 13 socket on a 1/4 inch short extension.
2. If you hear a ‘click’ from the starter motor but the engine doesn’t turn again use a good torch to locate the silver body of the starter motor, hold a screwdriver like item ideally made out of hard plastic against the silver body, if you can feel the ‘click’ noise is coming from the starter motor then it’s probably faulty. If you are very careful you can use a screwdriver but tape up the shaft to stop it shorting out on the starter wiring.
3. No click check the starter motor fuse. If it’s blown fit a replacement and if that blows most probably your starter motor is shorting out internally. Replace starter.
4. Check for loose battery terminals. On changing the battery sometimes tightening up the clamps is forgotten.

[ZenonWozniak]

That was as helpful as a choclate tea pot

[Vatierville]

Mines been doing the same - AA seems to think its the starter motor - had a new battery and made no difference...

[emilsommer]

Did you change starter motor in the end? I have the same issue. Have replaced battery twice now.

[joewentz]

Exactly the same problem on a Renault Twingo (which uses the exact same engine). Have you got any details on the fault or other cases?

[paulwatson]

Had the same issue and was told it was the alternator. Changed it but still it happens. Now been told it could be the starter motor or there’s a loose connection, draining the battery and stopping enough charge getting through. Makes a clicking/clunking noise when it doesn’t start properly so some signal is definitely getting through.