Gearbox Fault Warning Displayed

[newton1959]

Something new on my 2011 Berlingo Multispace automatic 1.6 Diesel.
Having fixed the brakes and the abs fault, I now have an Gearbox Fault Warning displayed intermittently. 

History. 
After driving for about an hour as I pulled away from a junction the gearbox was very reluctant to change from 3rd to 4th gear, note that the auto notice above the gear solected was flashing and the Gearbox Fault Warning Displayed. OBD tool deployed and no codes displayed. To clear the fault display I had to disconnect the battery and short the positive and negative feed cables for 15 minutes. The fault warning was now clear and the car drove with no issues for a few days.

Unfortunately after a few days while parking I had solected reverse gear and once again the auto notice above the gear solection was flashing and the Gearbox Fault Warning Displayed. Once again the OBD tool deployed and no codes displayed, I tested all fuses in the engine compartment and they were all good. To clear the fault display I again had to disconnect the battery and short the positive and negative feed cables for 15 minutes. 

I would be grateful if anyone on this fine forum would have any advice to help me discover what it could possibly be.

[Sol]

You will never get gearbox codes with an OBD scanner, you need DiagBox software and the proper interface. V7.83 from eBay will do it, if you get it and have a laptop with Windows 10 then let me know, I'll point you to a free VM version of DiagBox that needs no installation. But you need the interface, has to be Lexia / Actia full-chip version.

No one will be able to help with this without fault codes from the gearbox ECU. It could be anything at all.

There's obviously a fault with it but clearing the codes just hides the problem for a while. Eventually it will not reset.

[newton1959]

Thanks again Zion.

I was hoping it would be something I could work through myself with some simple testing. As I just replaced the double relay for the abs issues and it cleared those fault warnings I was worried that it may have been related.

[Sol]

I (and probably most of us) would love to be able to help with a bit of information to solve the problem, unfortunately from experience this kind of issue is less common and could be many things.

Without the means to get proper codes (and generic OBD readers are poor at the best of times, especially useless on anything that is not part of the engine (includes gearboxes) then troubleshooting by remote help will be impossible.

This could be due to the hydraulics to shift gears (if that is how it's done) or anything. The "auto" of Citroen is a "Piloted Manual" and not a proper auto gearbox. It's a manual gearbox with a robot clutch and a robot shift. From there, the issue could be the clutch systems, to the gear shift systems, to the electronic systems.

They are pretty rare so I personally have no experience of them. I doubt many people have.

[newton1959]

Thanks Zion.

From the limited amount of information that I have been able to find I think that a trip to the Citroen Dealership could be the next trip.
As soon as I discover what the issue is I'll post it.

[newton1959]

Update

Having checked and cleaned every fuse and electrical connection we still had this intermittent "Gearbox Fault" issue. As our code reader was not able to to display the fault we bit the bullet and took the car to our local Citroen Dealership. 

We live in rural France our local Citroen dealership is 20 miles away and unfortunately they don't speak English and my French is not great. 

However we managed to put together a page of English to French translation, a few hours later and €160 lighter we were informed that it was the "Contacteur de stop" 

Does anyone know what the "Contacteur de stop" is and where this is please.

[Sol]

It translates to "stop switch" which would imply the brake switch. That doesn't make much sense. But it could be that the brake switch is "making" when you aren't actually braking, this causes a coherence fault.

Mine was doing this, flickering the brake lights. On the RHD it is under a cover on the left (passenger) side, on a LHD it will be attached to the actual brake pedal. Check if this is the problem.

Remove the switch (it rotates anti clockwise and pulls out) then pull up the plunger on the top until a few more likes are visible, it makes the switch operate with a bit more pedal travel and prevents random operating when you're not actually braking. Mine had two ridges showing; it needed to be four.

See the attached pic:

[newton1959]

Thanks again Zion.
This was what they replaced today at a the Citroen Dealership.
Fingers crossed that was it.

[Sol]

Excellent. Mine was flickering the brake lights and the cruise would not stay on. Since finding and fixing the switch, it's been rock solid for months now.

[newton1959]

Update: Sadly after the Citroen Dealership had changed the brake switch the gearbox faulty warning has returned. We have only driven 200 miles before the fault warning reappeared. As before when the car was brought to a stop the fault warning cleared....
So frustrating....