Compared with the fortwo 450, the fortwo 451 petrol engines only have three spark plugs. We recommend changing these every 30,000 miles max. The last service we performed on a 451 Brabus showed significant wear on the electrodes which had travelled nearly 33,000 miles.

The spark plugs used in the fortwo 451 are Denso XU22HDR9 and have smart part number: A132 159 00 03.

To remove the spark plugs, the three coil packs need to be removed first. These can be found on the top of the engine and are indicated below:

Start by removing the electrical connections to the coil packs. There is a small latch on each connector which needs to be pressed first. Then remove each of the 10mm hex securing bolts on each pack.

the coil packs will then easily pull free from the engine. Due to limited clearance, these will need to be removed at an angle.

Remove the spark plugs with a 5/8" spark plug socket. Again, due to limited space, you may need to fit the socket before you connect it to your wrench - it all depends on the tools you have!

Remove the plug from the car and inspect for signs of engine problems.

Take your new spark plugs. These three are official smart parts but they are simply Mitsubishi plugs rebranded.

Inside, they are just Desno XU22HDR9 plugs.

Fit the new plugs and tighten to 18Nm. Replace the coil packs and tighten the securing bolt to 10Nm.

Start the engine and check that all cylinders are firing correctly.

An alternative to the Mitsubishi plugs are the NGK LKR7B-9 plugs which are equally as effective although not OEM.