EGS deactivation

[Ceenine]

My friend’s 2014 C4 Exclusive with EGS has decided to misbehave. Tootling along in top gear it drops out of gear for no god*******ed reason. If she accelerates it drops back into gear. Any clue as to why this would happen!. I have an earlier 2007 model and I have never experienced this. Seems to me that it must be electronic. It will get a diagnostic next week.

Cheers from COVID-19 free Tasmania. (Maybe not next week)

[Ceenine]

As an update, I suggested to my friend to use paddles to go up and down the gears. This method works perfectly which indicates that the clutch and gearbox are working without problem. So it is in the complex area of signals to or from the EGS ecu. Where the problem lies. So the next thing we will try is greasing up the two electrical connectors at the top of the gearbox computer(EGS ecu).

To reiterate, there is no error signal on the dashboard. Neither are there any codes showing up on a generic analyser. The major problem is when starting off from rest, the gearbox stays in first. The driver has to take her foot off the accelerator momentarily, and then reaccelerate. The car will move into second and then roughly move up through the gears.

The vehicle has travelled 54,000 km only.

[xantia_v6]

I would work on the assumption that it is a sensor problem, but you are working in the dark without a Lexia to read live data from the sensors.

[Ceenine]

Generic analysers not sufficient? A very competent PSA mechanic told me if there were no error messages on the generic aanalyser then a Lexia won’t be any more help. Do you have a different view?

[xantia_v6]

With a Lexia you can read the actual value being returned by the sensors, even while driving the car. Most generic readers don't have this capability, it depends on the reader.

The absence of fault codes could mean that a sensor or switch is returning a plausible, but wrong value that is causing the ECU to think that it is doing the right thing, but not.

With Lexia clones from China being so cheap now (if a little fiddly to install), I think it may be a good investment.

[wheeler]

Generic analysers not sufficient?

It really depends what you mean by generic analysers? There are cheap readers that only read Engine management systems. Then there are high end ones that will do almost everything that Lexia/Diagbox will do.
Bosch KTS for example will read all the ECU’s on your car and can even re program the clutch & gear change actuators.
I have also in the past had the odd occasion where Lexia is showing no fault codes but an aftermarket unit does.

[Ceenine]

Thank you for your very helpful replies. Unfortunately me and my Diagbox are here in Tasmania and my friend is in sunny Queensland , some 2000 km away and a big bit of water in between. I may send him to the local dealers who aren’t, terribly helpful Citroenwise being a multi dealer franchise but he will need to bite the bullet.

[Ceenine]

By the way, the gearbox works perfectly using the paddles behind the steering wheel