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Info guides and mods

451 Factory Cruise Control

Modification Details




This Is All Guesswork

A few people have asked me about retrofitting the standard 451 cruise control with the buttons on the steering
wheel. I have given them the information required but none of them have actually done it or got back to me.

Is Your Car New Enough?

Your car must be manufacturered after October 2010 (according to smart).

Do You Have The Correct Speedo?

All 451 fortwos with factory fitted cruise control came with the speedo with a trip computer.
The standard speedo didn't have the symbols to display the cruise control state or the set speed.

Do You Have The Correct Steering Wheel?

Actually finding a 2nd hand cruise control steering wheel is small, however, if you have a standard paddleshift
steering  wheel fitted to your car, you can just add the cruise control buttons, fascia and steering wheel wiring loom.

Buttons & Wiring - A451 905 10 00
Cover Panel - A451 462 03 95

If you don't have a paddleshift steering wheel, you'll have to buy one. Make sure you get one from a car manufactured after October 2010 (according to smart).

Do You Have The Wiring?

If your car is manufactured after October 2010, you should have all of the wiring necessary and they should
all be connected. However, you do need to double check before wasting your money on anything.

Steering Connection Number Wire Colour Connects To
1 Violet Airbag Controller pin 15
2 Pink/Black SAM Unit Plug 9 Pin 30
3 Grey/Blue Speedo Pin 12
4 Blue/Black ECU Pin 78
5 Brown/Green Speedo Pin 7
6 Green Airbag Controller pin 16
7 Brown Earth/Ground
8 Blue/White ECU Pin 81
9 Brown/Green ECU Pin 77
10 Blue/Pink Speedo Pin 15

You should have a wire in every one of the 10 positions. If you are missing
wires 3, 4, 8 and 9, you don't have the wiring required for standard cruise control.

Everything Good So Far?

OK, so you have the wiring, you have fitted the trip computer speedo and cruise control
equiped steering wheel and the cruise control doesn't work. What the hell?

This is the hard part. You have to go to a smart dealer and have the car coded to activate the cruise control.
The reason this is the hard part is that your smart dealer almost certainly won't have done this before.
They won't know what to do or how to SCN code the car correctly. They may even say it can't be done.

They do it at the factory so of course it can be done. You just need to keep asking until they work it out.

Working Cruise Control

Once the car is fitted with the correct steering wheel, speedo and coding, the cruise control should work correctly.

Do I Really Need A New Speedo?

There is a good chance that the car will work without upgrading the
speedo since all of the coding and computing goes on in the ECU.

The connection to the speedo is to light the LEDs in the cruise control buttons.
However, the ECU does communicate the state of the cruise control and the set speed
through the CAN bus to the speedo. If the cruise control relies on data being
communicated back from the speedo to the ECU, you will need an upgraded speedo.

At the moment, it's guess work. Try it and you let me know.


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