I would really like to get to the bottom of this – dropping into 2nd gear / safe mode

[Hogster]

Hi everyone

I've owned my 2010-plate Passion fortwo CDI since January 2012 and have done about 50,000 miles in it since – and have loved every mile!

However, maybe 1.5 years ago the car started suffering from a seemingly random problem which would shift the gearbox into 2nd gear, forcing me to stop the car. To 'reset' the car I would have to turn the engine off, switch the ignition on, play with the gearstick (go into R, N, 1st, R, etc) until the 3 flashing lines appeared (during which time the gearbox would make continuous gear-selection noises as if it were rapidly changing through all the gears), then continue playing with it until the correct gear number/letter was displayed. The number/letter would still be flashing at this point, but the gear-selection noises would stop. Finally by turning the ignition off and on again the number/letter would stay solid (not flashing) and then you could start the engine and drive off.

This has been such an irritating problem as it does not seem to have any particular cause. I might be selling the car soon and I really don't want the next owner to have to suffer with this same problem ... also I would like to get to the bottom of it myself! Below I have listed everything that I know about this problem and you'll start to see how random it is ...


FREQUENCY

• Happens much more often in cold weather, and even more so in wet weather. Very rarely happens in the summer.
• Only happens within the first 0-10 minutes of driving or so, and from memory only whilst the engine is still getting up to temperature.
• If it's happened and I've had to stop to reset the car, the problem will generally not manifest itself again during the rest of that journey –– no matter how wet or cold it is. Occasionally it's happened twice in a row, but more often than not, once it's happened on a particular day it won't happen again.
• Does not coincide with changing gear, accelerating, slowing down or any particular speed. I could be cruising along at 10, 20, or 30mph, accelerating or having just changed gear and it could suddenly happen ...
• After the engine goes into 2nd it does not allow me to change gear until I've 'reset' the car. If I stop the car and try to move off again the gearbox will stay in 2nd making the clutch slip like mad to get the car moving.
• Very rarely manifests itself if I'm travelling more than about 30mph. On the few occasions where it has, and the engine can't rev fast enough to allow 2nd gear, the gear number on the dashboard will just start flashing. As soon as I go below about 34mph it will then drop into 2nd (I'm fairly sure this is what happens although it hasn't happened above 30mph for ages).

POINTS WORTH KNOWING

• I have a MisterDotCom cruise control fitted in-line with the throttle pedal, and also a MisterDotCom trip computer which taps off the car's CAN-bus inside the speedo housing (and is also connected to the cruise control). Both of these were fitted a week or two after buying the car and this problem didn't manifest itself for at least a year or more after installing them. If either of these modifications were causing the problems, why does it seem so dependent on the temperature / moisture in the air? If it was caused by either of these mods I would expect the problem to manifest itself regularly throughout the year.
• Apart from the MisterDotCom equipment and better speakers, the car is otherwise a standard Passion model.
• Both S2 Smarts and Smart Specialist Guildford have been foxed by this problem. When connecting their diagnostic computers to car, it does report back saying the car has gone into safe mode but it's never listed the cause. The MisterDotCom trip computer also allows me to look at error codes, but nothing is ever displayed when the problem occurs – even the yellow warning triangle doesn't illuminate!
• When I took it into Smart Specialist they cleaned the connector leading to the gear-selector motor and also put water-repellant grease onto the terminals in case this connection had somehow been giving glitchy feedback to the onboard computer. This didn't appear to make any difference.

This problem has been driving me mad, and every time I get into the car (particularly in the winter / when it's very wet), I'm almost expecting the problem to occur. It's also been quite dangerous on occasions as it's not always possible to pull-over and stop – instead I've occasionally had to keep driving with the revs above 3,000rpm in 2nd gear (to keep up with the traffic) until I can find somewhere to stop.

If anyone has any thoughts, pointers or suggestions of things to try I would be very grateful – as the thread title says, I really want to get to the bottom of this!

Just before I finish this post, I seem to remember there was a lot of debate and irritation surrounding a problem with CDI cars going into safe mode around 2012? It was something to do with wires chaffing or rubbing in the engine bay and the cars had to be taken to smart for a warranty repair to fix the issue? My car had this 'fix' before I bought it, but given how random this fault seems to be, do you think this dealer modification might require a revisit? What was the 'fix' exactly? Can I look at it myself?

Many thanks for your help and have a wonderful Christmas

David

[tolsen]

I believe the 451 has two gear change motors. Suggest you swap them. Probably have to learn gear change positions on a star machine. I assume you already have chanced wiring harness. Strange there is no fault code.

[Hogster]

Hi Tolsen,

Many thanks for you reply

I never knew it had two gear change motors? Can you point me to any information on where I might find the motors? Neither Evilution nor FQ101 seem to make any mention of the gear change motors –– only the clutch actuator.

Regarding changing the wiring harness, I haven't done anything of that nature since buying the car. The dealer said the 'fix' had already been done to my car (to stop the car entering safe mode) when I bought it in Jan 2012. Can you point me to some information on the wiring harness fix? Maybe I can take a look to see if anything looks loose / amiss?

Yes the fault code one really puzzled me – there is evidently a problem otherwise the car wouldn't go into safe mode ... but surely going into safe mode is a serious enough issue to generate a fault code, or at least illuminate the yellow triangle!

Thanks again for your help and have a wonderful Christmas ... in 34 minutes!

David

Edit: is the wiring harness problem about this? From Evil's site:

The forth issue is a boost pressure sensor for the EGR (Exhaust Gas Recirculation) valve. However, for once,
the sensor doesn't fail. It just receives incorrect data. The fault was a strange one that took smart a while to
figure out. The sensor is piezo transducer which can measure pressure deflection and vibration. The problem
was that part of the wiring loom or brake vacuum line was running close to the sensor and eventually started
vibrating and tapping the back of the sensor. This caused a malfunction which created an excessive vacuum
which in turn opened the turbo wastegate and caused a massive loss of power and a stored fault code of P2359.

[tolsen]

There are definitely two gear change motors but they may be housed as a pair hence not possible to swap. More info in below document:
http://somesmart.info/reference/2008fortwotech.pdf

[Evilution]

Feel under the passenger carpet to see if you can feel any wetness. The gearbox controller can suffer from water ingress causing all kinds of gearbox issues.

[Hogster]

Thanks for the tips guys!

Evil –– is the gearbox controller obvious when I lift up the carpet? I can't find any information about it on your site ...

Many thanks!

David

[tolsen]

See page 57 of document linked to in post 4.

[Hogster]

Ah yes I see it now –– that's a very useful document, thanks for sharing the link!

I will have a look to see if it's getting at all damp.

Do you know if it's an expensive part should it need replacing?

Many thanks!

David

[earthman]

Ah yes I see it now –– that's a very useful document, thanks for sharing the link!

How long does this link take to load? I can't get to see any of the diagrams etc, I do have a broadband connection rather than a dial up one. LOL

[Hogster]

It's a 40.9MB file so it does take a while to load, even on broadband! It's got loads of photos and graphics in it which probably explains its size ...

[Hogster]

I can't find the pesky thing! Is the gearbox controller hidden under the carpet somewhere?

Looking under the driver's seat, all I can see are lumps in the carpet ... is the gearbox controller under the lump indicated below?



If that is the controller, I can't see how the carpet can be lifted without undoing the big Torx screw holding the seat slide-rails down?

Am I missing something obvious here?

The carpets don't feel at all wet by the way ...

Many thanks for your help!

David

PS. I looked on the passenger side as well and it's the same situation –– lumps which might be the controller under the carpet, but no way to lift the carpet without unscrewing the slide-rail ...

[tolsen]

You need to remove left side seat.

[Big Performance]

It is a Mitsubishi ECU or TCU depending upon your spelling. Held in with bolts and has an earth lead attatched. Two large electrical plugs go to it

[Hogster]

Ah right, so I need to remove the passenger seat (nearside) and then I'll find the box that Big Performance has described underneath the carpet?

Do the Torx screws holding the seat in need to be tightened to a particularly torque ... or is 'jolly tight' good enough?

Many thanks for your help

David

[Evilution]

I did say passenger seat. You only have to remove the seat to see the controller (sometimes also called a GDU) but you can reach under the carpet from the front. Water isn't selective, if it's wet under there, it'll be obviously wet. The GDU doesn't need coding, you can get one from a similar car and plug it straight in. I don't know if they are simular between different models, I expect they'll be different software depending on the gearbox ratios.