Smart Fortwo 450 knock sensor replacement

[KZsolt81]

Hi Everyone,

I have an issue with my wife's 2007 0.7l(?) petrol Smart Fortwo 450. I need to change the knock sensor but I'm confused as in different medias I found different specs where it is mounted. According to the service manual I have, it should be under the exhaust system, where I can see a proper place for it but niether sensor is there nor cable for it amd not even tap in the mounting hole. Other docs says it is somewhere between the alternator and the starter motor. I can't see anything there from the AC compressor from above and neither anything from below because of the engine's position.
I have 3 questions.
First, which I doubt, was there any models without knock sensor (apart from diesel and electric )?
Second, how much would it cost roughly (labour rather than part) to change it by a Merc service?
Third, can I change it without proper garage, e.g. on the street (even if it is a big job)?

Many thanks for your inputs.
Zsolt

 

[Bellow]

Search
''This sensor sits on the back of the engine up against the firewall''

Evilution - Smart Car Encyclopaedia
''Where Is It?
On the back of the engine near the alternator.''

All petrol fortwos have knock sensors.

Not a job I have done but at a guess the aircon will likely have to be moved for access - and other stuff besides possibly - usual fortwo. MB dealers should (I'd have thought) have a time for this that they should be able to multiply their hourly rate by.
Removing the sensor will be child's play - once you have accessed it. Neither of the guides are showing 'how to'. It will be a case of removing everything in the way until it can be accessed. AC the biggest hassle - unless it can be sidestepped without breaking into the refrigerant circuit.

Depending on just how bad access is, lowering a 'corner' of the engine by detaching an engine mount may help - or go the whole hog and lower the subframe. It's designed for this and long supporting bolts are available for the purpose but there's an in between where the (longer) rear bolts are used at the front and the rear of the subframe is otherwise supported. Lowering the subframe may obviate having to disturb the AC.

 

[KZsolt81]

Thanks for the answers. That confirms my fears...

 

[grober]

Best I CAN DO. these guys can answer your question if you join their forum
Evilution - Smart Car Encyclopaedia
Identifying sensors

 

[Bellow]

OP: Where are you based?
There may be a smart indie that is more able to deal with this than either main or indy MB garages.

 

[grober]

Evilution - Smart Car Encyclopaedia

 

[Bellow]

Best I CAN DO. these guys can answer your question if you join their forum
Evilution - Smart Car Encyclopaedia
Identifying sensors

That isn't a forum as we know them but Kane's repository of all things fortwo (and Roadsters). The actual smart forums are pretty quiet these days but a question will get an answer - eventually.