C3 stop start warning- how to reset

[charentejohn]

Can anyone help please, C3 petrol 2006 stop start sensodrive.
I had previous problems, weak battery I think, which said stop start fault (in french) and after fitting a new battery it has done it again. Yuasa recommnded battery 65ah 640a

I replaced the battery doing the wait 10 mins door closed bit etc so hoped it was ok.
Seems not as the message still there, can I reset the computer myself. I also had a frost warning with oa outside temp of 9c showing so think it is confused.

Any help appreciated John

[GiveMeABreak]

There's not a lot of info on these early stop start systems, but if they are anything like the modern versions, there are a lot of conditions that have to be met before the Stop Start system will operate.

One of these conditions is relative to the outside temperature. If the temperature is not within a determined range, then the system is disabled - especially at colder temperatures. So considering you have also mentioned the exterior temperature sensor is on the fritz, this could be sending false readings to the systems.

I would first consider changing the outside temperature sensor in the wing mirror first as this is obviously faulty if giving incorrect readings and then see if that does not resolve the other issue.

[charentejohn]

Thanks, good thoughts. I will drop it into my local garage and see if they can do a reset.
I did find something but it needs a remote central locking key and I gon't have one, long lost.

[wheeler]

The first C3’s with stop start also had a small second battery under the passenger seat (on a RHD) for the stop start system. Its like a little motorbike battery. Check if yours has this & might be worth having it tested. Yours will probably be a full CAN model so the system may have changed.

[wheeler]

I did find something but it needs a remote central locking key and I gon't have one, long lost.

Cant think what that could be??

[charentejohn]

Wheeler, this is the BSI, which may just be the open doors bit. No idea why, this is a modern one so similar

Just been out and oild oil pressure low warning again, see this thread as related. viewtopic.php?&t=70686
Engine seems to run ok. Checked and the temperature is reading correctly, the problem yesterday was at 9c it said ice warning. Obviously a bit confused.
I also got the stop start message.

I have seen the idea of disconnecting the battery and shorting the terminals to power down the computer. I would assume this is safe ?
It should then apparently self check and correctly (we hope) calibrate all sensors etc. It should then show genuine problems only, I am hoping the low original battery caused these but the new battery is not helping till they are completely cleared ?

Garage is closed until monday.

[wheeler]

I have seen the idea of disconnecting the battery and shorting the terminals to power down the computer. I would assume this is safe ?

I take it when you say short the terminals you mean short the battery leads? No, never do this, dont short the battery leads directly after disconnecting the battery. Connect a bulb across the lead to discharge any residual current. The other issue with doing this is like i mentioned earlier your car may have a secondary battery for the stop/start system under the passengers seat, if this was still in the circuit too it could look like someone mig welding.

As for the remote control thing, usually after resetting the BSI you need to resync the remotes as they may not work after the procedure, if you dont have a remote then this bit just wouldn't apply.

[charentejohn]

Thanks for the warning wheeler, I will check for a battery under the seat and use a bulb to discharge the memory. I will try the garage tomorrow to see if they can do it properly with a lexia, I notice the new ones have a touch screen with a return to factory settings option.
I will change the oil pressure sensor today so that a reset will include all sensors rather than do it the change something.
I read that, having changed the battery, the car needs to recognise it as new. I am hoping the old battery (there since 2006) failing caused a problem, the computer remembers it and the new battery needs to be recognised to sort things out. The old battery charged at a high rate and went back to 1 bar on the charger next day, then recharged to 3 bars out of 4 in an hour. That said it would start the car no problem, wierd.

I will report back when they have rest the computer and let you all know if it worked.

[wheeler]

Thanks for the warning wheeler, I will check for a battery under the seat and use a bulb to discharge the memory. I will try the garage tomorrow to see if they can do it properly with a lexia, I notice the new ones have a touch screen with a return to factory settings option.

I would have thought that was just for the touch screen system rather than the whole car??

Just noticed you are in France so when checking for the auxiliary battery have a look under both seats, on RHD models im pretty sure it was under the passengers side seat so dont know if it would be reversed foe LHD. The battery may not be immediately noticeable as it is located inside a plastic box.

[charentejohn]

Thanks again, I do think it has a secondary battery as the handbook says so.

Changed the oil pressure sensor and still a problem, on the upside it should be complaining when I get to the garage so they can see it.
Didn't get a Stop Start message this time but still don't trust it not to appear. Hopefully a reset, basically a Lexia shorting the leads safely, will sort it out. I did note that disconnecting the wire to the oil pressure sensor did not produce the error message, so assume it is energised till the pressure rises then disconnects. At least I have one way to do it.

[charentejohn]

Problem solved, phew.... They checked and it was the wrong oil filter which restricted the flow, only steady long runs so no harm done I imagine. Garage changed it and renewed oil with an apology and no charge, as expected.
The Stop Start was cleared so we shall see if it stays away, else I will look into the battery under the seat.

At least having changed the battery to see if it cured it the car drives much better. Being sensodrive the battery needs some power to operate the clutch, I was sometimes getting 'thumpy' changes when moving from a standstill.