Category: 451

Where is the Smart car battery located?

The battery can be located under the carpet beneath the area where the passenger foot well, you need to ensure all electrical devices are off, lift the carpet and remove the foot support (usually secured by 2 fasteners) by sliding it out of the car sideways, first unscrew the negative then the positive terminal.

*safety note potential hazard item*

When driving my Smart car slowly I get a weird spring sensation through the brake pedal and a noise to accompany it?

Have someone check the ABS reluctor rings (they are at the end of each rear driveshaft), these corrode and split over a period of time making the ABS not work when it should be, the split rings give incorrect signals to the ABS sensors that in turn makes the ABS pump unit work when it is not required.  Fit new driveshafts or have a qualified person replace the ABS timing rings.

*safety note potential hazard item*

I have a performance exhaust on my Smart car and my engine light has come on, is the exhaust faulty?

No not necessarily, the smart car has set parameters for all the engines settings, by changing them from standard you run the risk of the engine management unit thinking there is a problem.  Changing any part of the car can cause this but exhausts and air filters are most common.

NB. You can buy a unit that fits between the exhaust and lambda sensor that alters the reading reducing the chance of the engine light coming on.

The heating fan in my fortwo only works on full, why? [451]
It needs to be checked and the correct problem identified. Usually a new heater control is unit fitted (the bit with temp scale on it - see if yours is in warranty or not).
My headlight bulbs have gone again is there an easy way to change them myself? [451]
Yes, refer to your manual for how to change the headlight bulb.
My Smart Car’s handbrake travel is very high, why?
It's probably the rear shoes and adjusters that need cleaning and adjusting properly, these usually get done about every 4th year - it could be the rear wheel cylinder seals have failed and are weeping brake fluid. A competent garage can remove the rear hubs and clean and inspect the cylinders and replace and adjust as necessary.
Why does my Smart car have 3 little lines in the centre of the dash?
Usually 3 lines relates (shifting system fault) to a electro/mechanical problem with gear selection rather than a signal control problem see gear selection Q and A
Why does my Smart car have 1 little line in the centre of the dash?
1 Can bus malfunction - the line usually indicates a system fault usually a signal or communication error, this really needs to have diagnostics run by someone experienced with a star machine and Smart Car knowledge.
How much oil do I need in my Smart car? [451]
451 petrol: 3.3 litres / 451 diesel: 2.7 litres
My paddle steering wheel is not working properly. It does not change gear on one side properly or it is intermittent, what might be causing this?
It's probably the steering wheel angle sensor which has failed, these cannot be bought separately, only as a whole steering wheel. The problem needs a diagnostic machine to verify, if this is the case a new steering wheel is the answer. The car looks to the steering wheel angle sensor to see how much steering input you have when deciding how to brake safely in an emergency. Safety note: the ABS and ESP may not work properly in an emergency if these are faulty.
Can I tow my Smart car? [451]
Yes, see page 245 of the manual. The ignition must be switched on. If the car is being towed, **the gearshift lever must be set to position N and the dash read N for neutral or you risk terminal engine damage** If you have had gear selection problems do not tow. *safety note potential hazard item* Towing notes: Only people with a certain amount of experience should tow. A metal tow pole is the best option *safety note potential hazard item*
My Smart car battery is flat can I bump start it? [451]
Yes, see page 244 of the UK Smart 451 manual This is the procedure from the manual for the 450 / 452 always make sure it is safe to do so *safety note potential hazard item* Turn ignition to position 1 Put the handbrake on Press the footbrake and hold Hold the gear lever in the forward + position Release the footbrake Press the accelerator to the floor (while stationary) Release the handbrake and start rolling (you need a good shove though or steep hill) Once moving the clutch will automatically engage and the engine will start
My Smart car diesel is going very slow like it has no power / intermittent power loss. [new 451 cdi 2007 onwards]
The issue is usually a transfer of vibrations to the pressure sensor of the EGR (Exhaust Gas Recirculation) unit. The remedy is to fit a bracket to hold the components apart a minimum distance of 10mm thus reducing vibration transference and component failure / malfunction (main dealer if in warranty) and there should be parts available to rectify this from your dealer.
My Smart car won’t start and it shows a little key symbol in the centre of the dash, why?
The immobiliser is still on. It turns itself on automatically after 60 seconds if you have not started car after unlocking it. Remove the key and unlock the car again. Then, replace the key and start as normal. See next section.
My Smart car key unlocks the car but won’t turn off the immobiliser, why?
It likely the key has lost its coding (9 indicator flashes should accompany this when pressing the key fob unlock or lock button if it's faulty) and will have to be re-coded along with the car and any spare keys you might have too. They all will have to be taken to someone with a Star Diagnostic machine to re-code them all together. Its worth getting an additional new key before so you can get it coded at the same time, if you don't already have a spare key.
My key won’t unlock the car, is the battery in the key fob low? [451]
It could be. It's more likely that the key has fully discharged, lost its coding and will have to be re-coded along with the car and any spare keys you might have. Try to use both keys equally and often to prevent losing the coding. There has been no satisfactory explanation as to why they do this. If the battery is low the indicators will flash 9 times quickly (indicating you can use it 100 times more - so change the battery asap). When changing batteries observe correct polarity and change them promptly. Batteries are available in many retail outlets and garages. The battery size is CR2016. See the handbook for how to replace the battery.
The radio and wipers are not working on my Smart, can you help?

Applies to: 451

Yes. First check fuse 20 for the radio and see if that fuse has blown, replacing it if it has blown. Then check if the radio works, if ok then check the wipers, if the fuse blows its probably the wiper motor burnt out from the wipers being turned on when the wipers were frozen to the screen or the wiring to the wipers being faulty / damaged or damaged / faulty wiring and it often knocks out the radio fuse too.