The hardware as well as the software of the X-Gauge were explicitly developed for the fortwo (gasoline/petrol and diesel). The X-Gauge will, however, also work in the smart® roadster since it shares its engine and ECU with the fortwo. But a solution for housing and wiring of the X-Gauge in a smart® roadster is not readily available as it is with the cockpit clock in the fortwo. Regarding any other car, it would be pure coincidence if its ECU would respond correctly to the X-Gauge.

No, the X-Gauge can only be delivered as a kit. You must provide the cockpit clock yourselves. If your smart® is not already equipped with one, you'll either have to buy one from a smart® dealer or, if your lucky, you might be able to get one from a salvage yard. Only the plain case, the two plastic button plugs, the plastic screen, the decorative color ring and the 2 mounting screws are actually needed.

Lets put it this way: if you're able to change the bulbs of your smart®'s driving lights yourselves, you're probably capable of installing an X-Gauge. Seriously, read through the entire installation guide in order to get a feeling for doing the job yourself. If you do not feel comfortable with any of the required procedures, you should have someone qualified do the job for you.

Yes, if you've kept all parts from the cockpit clock that were not needed for the X-Gauge conversion then you can put the clock back together at any time. No parts of the clock get altered in any way. Only the 3-wire cable that was removed from the clock module must be re-soldered.

Not at all. When ignition is turned off, the X-Gauge actually draws less current from the battery than the original cockpit clock.

No. All the X-Gauge does is sending requests to the ECU for receiving selected parameter data. If the ECU is not occupied with any higher priority tasks it will respond to such requests.

Yes. The mechanic can unplug the X-Gauge's OBD connector at any time in order to connect his diagnostic equipment instead. Just make sure that the X-Gauge's OBD connector gets reconnected after the mechanic has finished his diagnosis, otherwise your X-Gauge won't work properly anymore.

The top right pixel of the display is used as an indicator that is lit (sometimes flashing) whenever parameters are retrieved from the ECU. It stays dark when no data between the X-Gauge and the ECU is being exchanged (e.g. all assigned parameters of the active display mode are non-ECU parameters).

No. The X-Gauge is a monitoring device only.

So far we have driven our test smart® with a connected X-Gauge for over 50'000 km with continuously monitoring various ECU parameters and we have not encountered any problems whatsoever. The additional processing load that the X-Gauge puts onto the car's ECU is insignificant as compared to the ECU's main processing tasks. Common engineering sense would also suggests that if the ECU would run into a processing bottleneck due to an OBD request from the X-Gauge, that this request would simply be ignored. Besides, there are commercial OBD logging devices available which also stay connected to the interface continuously. If you are still concerned, just assign all non-ECU parameters to the display mode that you use for daily driving. That way no communications will take place over the OBD interface.

The diagnostic interface in smart® cars before model year 2001 (Gasoline/Petrol) or before 2004 (Diesel) simply does not deliver the generic engine parameters that the X-Gauge requests from the ECU. This feature has been added to the ECU starting with model year 2001/2004.

The X-Gauge displays ABSOLUTE intake pressure that the ECU reports from the engine's MAP (Manifold Absolute Pressure) sensor. All the ECU is interested in is absolute Pressure. RELATIVE intake pressure (boost or vacuum), the one that you are rather interested in, is given by:


A fixed ambient pressure can be set via the user menu so that the X-Gauge will display a relative intake pressure (negative values for vacuum, positive values for boost). Ambient pressure is, however, dependent on altitude, temperature and weather conditions so that the relative pressure display can only be accurate within these limitations.

If someone will foot the tooling costs to have a custom display made at low quantities then we're all for it. We had to go with a readily available display. Even though it might seem small, we can assure you that it is very readable from the driver's position, including the parameters that are displayed in the smaller font. Besides, the OLED technology of the display has many advantages in an automotive environment. It works without getting sluggish at temperatures as low as -30 degrees Celsius, its viewing angle is quite wide and it does not require any backlight. The only situation when its readability suffers is when direct sunlight is shining onto it, but this is a problem with any other display technology also.

We have driven over 50'000 km with an installed X-Gauge and even reading data that is displayed in the smaller font has never been a problem. Believe us, it's very readable, without having to squint your eyes at all. The picture on the home page that shows the X-Gauge on our smart®'s dash may be a little deceiving regarding readability.

Starting with model year 2007 (fortwo 451), smart® has changed to a newly mandated OBD protocol (CAN-Bus) that the X-Gauge has not implemented. In addition, the clock pod itself is different and will not accommodate the PCB of the current X-Gauge hardware.