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EGS Calibration in Diagbox

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Author Post
Fri Jul 27 2018, 11:24am
Member No: #51717
Joined: Jul 24 2018
Location: Manchester
Hello all,
I just got a 2008 C4P. It was juddering at low speeds, fairly violently sometimes I thought. I haven't been in any traffic jams yet but I imagine it would have been a real pain.

The hard reset was fun but ineffective. I had the software update done at my local garage, which made absolutely no difference. They did wash it afterwards though, so I'm looking at it as a £119.99 car wash.

I had bought a Lexia 3 setup to enable the Aux In (rather than pay the dealer £60 - this kit was almost the same price). I couldn't get Lexia itself to work, but Diagbox works fine. All the instructions for EGS calibration seemed to be in Lexia, but I tried it in Diagbox 7.02 via the following menu options (can't remember exact wording but similar to this):

Pack reparation
Replacement parts
Gearbox programming

(sometimes you have to make the same selection twice).

Eventually you should see "Programming of the Transmissibility of the Clutch". The first steps are straightforward. Just follow the instructions. You'll need to have a cool engine at the start. Then you'll need to sit there for 20 mins in neutral. So really you want an abandoned space that's not too far away, so you don't have to wait too long for your car to cool.

When you get the screen with the really long instructions, you have to work through all the instructions while they're still on the screen: do not press forward until you get to "If OK, switch off the ignition..." When you press right, it will prompt you to switch off the ignition, then do a 60s countdown.

The results were good: it's really smooth at low speeds now. I feel like it might be a bit clunkier and there is some judder when pulling away, so I'm going to recalibrate later when I can get to an abandoned carpark (even though you are only getting up to 2nd gear, you do need quite a bit of space where you're not going to be bothered - you have to start and stop 20 times in all - and I think I might have been lifting off slightly before it was ready to change into 2nd).

I will add to this after my next recalibration. I think this is going to be a process of refinement. I hope to ascertain exactly what 80-140Nm of engine torque constitutes (I guessed this time...)

Please please do this at your own risk. I am not saying whether this is a good idea or not. I have no idea what it will do to your car. One Citroen dealership warned me against having the clutch calibrated as it might cause more problems, whereas one was happy to do it. And I've heard from others that dealerships are reluctant to offer the calibration. It's still not entirely clear for me - hopefully this will turn out to be a good idea...
Sun Jul 29 2018, 04:58pm
Member No: #51717
Joined: Jul 24 2018
Location: Manchester
Update: I figured out where to get the torque info:
Gearbox -> Standard Parameter Measurement -> Engine Information

Turns out 80-140Nm isn't that much. I think Lexia recommends about 45% throttle and it felt like that.

I recalibrated with the correct torque and the judder is back.. Not at low low speeds like it was before, but at about 5mph - it feels worse at that speed and more of a problem for parking.

As I said, I was applying higher than the correct torque previously and that seemed to remove the judder, but the gear changes seemed a bit off. I'll try again somewhere in the middle...
Thu Aug 16 2018, 03:54am
Member No: #51717
Joined: Jul 24 2018
Location: Manchester
Update: I recalibrated with a little more throttle and now it's much better. It's still a little unrefined when it's cold, but on the whole it's nice to drive now.
Tue Oct 30 2018, 03:05pm
Member No: #52423
Joined: Oct 30 2018
Location: Fife Scotland
Thanks mate for the info... the troublesome C4 coupe that I wrote about on my post today also has a less than perfect gearbox response when it pulls away... partularly when cold. At some stage I'll think about whether that can be improved upon if I fix my injector problem.
I don't know what you are referring to as a hard reset... it that a euphemism for wasting money at a main dealers? We've all done that.
Tue Oct 30 2018, 05:36pm
Member No: #27768
Joined: Oct 13 2012
Location: Hove
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