Ongoing EGR? / Limp mode / Cruise control issues

[reds]

The 13.4v was while running? At the battery it should be 14.4v and 13.4v at the OBD adaptor. But this voltage is coming from the alternator, not the battery.

The battery only starts the engine. The alternator provides the rest once running.

If you don't change the battery then you may be stuck with the starting problem. Limp mode is not battery related but starting easily with a fully charged battery certainly is a sign the battery is not getting to full charge when running. If the starting issue comes back after a few days and only goes away when the battery is fully charged at home, then it's either a bad battery or bad alternator. 13.4v at the OBD socket means the alternator seems fine. At the battery then that's not fine and is too low.

You could have more than one issue. We can only help so much on a forum; the rest is up to you or a mechanic / auto electrician I'm afraid.

How do you know full power is not being delivered? Limp mode has two settings, 3000rpm and 2500rpm, even in neutral. Anything else is not limp mode.

Otherwise, your turbo could be shot, you could have an air leak, a boost leak, a faulty fuel pressure sensor / regulator, clogged fuel filter, many things.

When was it last serviced and the fuel and air filters changed?

Does it have any fault codes now?

What rpm does it stop at when revved hard in neutral?

If it goes all the way then it is one of the issues above, not limp mode. I put up a Citroen tech training document in the how-to section on limp mode, what causes it and how to test it. Have a look at that. It's in the top section of permanent threads.

its 13.4 at the ECU

In terms of the limp mode, it revs up fully, but when going up a hill it doesnt accelerate as it would normally. It varies by day, some times it runs as expected, others not

Alternator and fuel rail have both been replaced in the last 12 months, at is has 161K with full service history, next one being due in 1,500 miles

Appreciate it should go to a garage now, but we have poured so much money into it now, I think we are probably call it a day !

Appreciate all of you input on the matter !

[Sol]

No worries mate. This is not actually limp mode then. Which rules out a few things. Read that document I mentioned. It will tell you what's not wrong. Limp mode limits the rpm to an exact value.

Maybe it's just worn out. 161k is a fair chunk of mileage. Maf? Low airflow means low fuelling. I can't remember the year. Maybe your DPF is clogged but you've had someone reset it without changing the actual dpf itself or cleaning it?

Feels like we're not seeing the whole story.