≡ On The Speedo 451
Three horizontal lines on the speedo LCD indicates that there is a fault in the gearshift system. There are a few reasons for this to happen.
Mod difficulty:
Mod Credit: evilution
This page ONLY covers the fortwo 451 (late 2007 - present)
Information
This is the symbol that will displayed on the speedo if a shifting problem occurs.
What Can Cause It?
The smart gearbox relies on a lot of electronics to keep it working properly, it only takes one
part to misbehave to call up an error code. Causes can be one or more of the following:
Weak Battery
It seems it is possible for the battery to be too weak to move the gear motor fully.
As the gears attempt to move and fail, the error code is bought up.
Fix
Get the battery tested and replace if it is faulty.
Wet AMT Controller
The AMT (Automated Manual Transmision) controller is situated underneath the carpet under
the left hand seat. Unfortunately it is also perfectly positioned to suffer from water ingress.
The 3 main causes for water under the carpet on this side are:
Leaking windscreen
Faulty door seals
Faulty air conditioning drain
No matter the reason for the water's presence, the AMT controller isn't waterproof.
Water easily enters this electrical device and causes problems with the transmission.
There is no drain point under there so water can build up over a long time.
We are only starting to see this common problem from late 2011.
Fix
Remove and attempt to carefully dry the AMT controller or have a new one fitted.
Track down and fix the leak that caused the fault.
Car Dragged In Gear
Site reader Billie W had his 451 dragged onto a car transporter because of a parking dispute.
After the dispute was rectified and they gave him his car back it displayed ≡ on the dash.
It is my belief that the engine and gearbox had tried to move and had jammed.
In these circumstances Billie found that the roadside fix (mentioned below) helped.
This is the symbol that will displayed on the speedo if a shifting problem occurs.
It seems it is possible for the battery to be too weak to move the gear motor fully.
As the gears attempt to move and fail, the error code is bought up.
Fix
Get the battery tested and replace if it is faulty.
The AMT (Automated Manual Transmision) controller is situated underneath the carpet under
the left hand seat. Unfortunately it is also perfectly positioned to suffer from water ingress.
The 3 main causes for water under the carpet on this side are:
Leaking windscreen
Faulty door seals
Faulty air conditioning drain
No matter the reason for the water's presence, the AMT controller isn't waterproof.
Water easily enters this electrical device and causes problems with the transmission.
There is no drain point under there so water can build up over a long time.
We are only starting to see this common problem from late 2011.
Fix
Remove and attempt to carefully dry the AMT controller or have a new one fitted.
Track down and fix the leak that caused the fault.
Site reader Billie W had his 451 dragged onto a car transporter because of a parking dispute.
After the dispute was rectified and they gave him his car back it displayed ≡ on the dash.
It is my belief that the engine and gearbox had tried to move and had jammed.
In these circumstances Billie found that the roadside fix (mentioned below) helped.
Fix
Smart have managed to give us a way to reset and reteach the transmission.
Euro Style Transmission
Place the gear lever into the N (neutral) position,
Start the car (jump start if required),
Press and hold the brake pedal,
When complete, the
Drive the car away.
US Style (Fake Auto) Transmission
Place the gear lever into the P (park) position,
Turn off the engine and wait at least 30 seconds,
Start the car (jump start if required),
Wait for the transmission to complete the teach-in process,
When complete, the
Drive the car away.
The teach in process can take 30+ seconds so sit patiently.
This info was well timed, it was taught to me by Rob of S2smarts the day after I wrote this page.
The 451 and Forfour have very similar clutch actuators. Bigger motors and
stronger compens
Unfortunately it would seem as though the spiral gear that transfers the rotational
movement of the motor to the linear movement of the push rod isn't up to the job.
Rob has seen far too many of these breaking for it to be circumstantial.
Closer inspection gives no clear indication as to the cause but the lack of shear would point to contaminated metal, an inherent weakness or brittle (over hardened) material.
Amazingly this physical fault only brings up ≡
Fix
Buy and fit a new clutch actuator. These really aren't cheap so ensure you log a complaint about
this part and try to get smart to replace it free. It's not a part that should wear so it should last
the lifetime of the car. The more people log this fault the more smart will pay attention.
Chieftmc of SCOA had problems and had to replace his clutch actuator. WhiteNBlack08
got the faulty part and took it apart to see if he could work out what was causing the fault.
Here is the offending artical. Similar to the ForFour clutch actuator.
Using a Torx screwdriver the cover plate was removed to reveal the internals.
There are no surprises in here, it's very similar to the 450 actuator but much bigger.
After struggling to remove the crescent gear from the main pivot shaft it was clear...
...that rust had formed on the shaft possibly increasing resistance in the movement.
This is a worry considering it is essentially a lubricated sealed unit and was a part that
was supposed to be left unserviced for the life of the vehicle. If the rust was a contributing
factor to the failure of this actuator I can see this being a common fault.
Obviously stripping the unit down isn't ideal so I would recommend spraying the internals
with a penetrating lubricant once a year and then white lithium grease a few weeks after.
This should allow the lubricant to get in and stop rust formation whilst the lithium protects it.
More stuff will be added as and when I find out causes and fixes.
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