Xantia 1.9TD "K" Light when coasting

[Zelandeth]

Noticed twice over the last few days that the engine management warning light on my Xantia is occasionally popping up when coasting downhill. I tend to use engine braking quite a bit, so that happens pretty often. The moment I touch the throttle it goes out again.

Anyone know the likely culprit before I try to arrange a session on the Lexia? EGR valve seems a favourite for many things!

She's an S2 Xantia 1.9TD running an XUD9TE power unit, currently on 199,500 miles.

[MikeT]

I don't believe the EGR has any such feedback mechanism (mine's isolated both mechanically and electrically) so if your fuel filter is good, I would suspect throttle pot first as that seems relative. Has anything been disturbed recently?

[DickieG]

It's almost certainly down to the signal from the injector needle lift sensor being weak and conflicting with the info from the pump, had this issue on one of mine from new. Citroen tried many different ways of solving it but never quite managed to sort it out, either spend loads of time and money on replacing the injector, soldering connections, replacing ECU's the list goes on or simply ignore it and live a happy life as it doesn't affect anything other than annoy you.

[Zelandeth]

Fuel filter was done two or three months ago. I'll have a check next chance I get that it's not drawing air in or anything silly like that.

Can the throttle pot be checked with a meter? Assuming we might be looking at a dead spot on the track. Not impossible after 200K miles I imagine!

If it's just "one of those things" I'm happy to leave it be. Just seems odd I haven't seen it until the last couple of weeks having had the car since November. Remember spending ages trying to track down why the check engine light in my Lada Samara flickered sometimes at idle...after about three months I crossed paths with an ex dealer who informed me that about 75% of them just did that! So long as it stays out when driving, don't worry.

I did adjust the throttle cable a week or so back (it was really slack), is it possible that this is a factor?