Smart fortwo 451 Gearbox / Transmission Software Updates - TCU

The 451 Smarts (2007-2014) can suffer from many issues with the transmission. It's good practice to get your clutch calibrated on a regular basis to ensure the best from your Smart.

4 Smart offer a clutch calibration service While you wait for £36. Please call us on 01242 374727 to book an appointment

We can also supply refurbished TCU's for all models of 451 coded to your vehicle

Failure to select reverse gear

Many Smart owners complain they struggle to get reverse gear. It can be very frustrating especially in busy traffic. It can be as simple as a brake light switch failure but very often it is something more serious.

Transmission Control Unit Software Updates

A TCU Software update can resolve many issues including the failure to engage reverse and the flashing N Although there are other reasons for both flashing N and reverse failure its is always a good idea to try an update first as replacing a clutch etc can become a costly exercise.

Flashing N

There are several reasons your Smart displays a flashing N If the flashing N is displayed in conjunction with 2 x maintenance spanners and the car appears to drive as usual a software update can often fix this.

TCU Software Updates

At 4 Smart you can book a while you wait appointment (40mins) or we offer a postal service for Smart 451 TCU software updates.

The 451 TCU Software update costs £84 + vat Please call us if you wish to book an appointment to have the latest software applied to your 451 TCU.

Smart 451 TCU Location

The TCU in a Smart 451 is located under the passenger seat on a UK RHD model. You will need to remove the 4 x seat frame bolts, lift the seat and the carpet to reveal the control unit. Then simply unplug and remove the TCU with a 10mm socket

Postal Service

Once you have removed your TCU Package it well and send to us with a not enclosed containing you Vin No and cantact deatails. We will apply the new software to your TCU the same day we receive it and it will arrive back with you by 1pm the next working day.

We use Royal Mail Special delivery guaranteed by 1pm the next working day at an additional cost of £11 + Vat UK mainland only.

Refitting The TCU

After refitting you will have 3 bars displayed on the dash. Don't panic simply turn the ignition off and press and hold the brake pedal. Turn the igntion back on and keep your foot on the brake until you see "N". You will hear the transmission doing its caliberation during this process.