P Level Low Error

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ne8ryan
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Joined: 14 Jan 2025, 12:20

P Level Low Error

Unread post by ne8ryan »

Hello,
just refuelled my car and got back to a "P Level Low" error with a service light on the dash,
I understand from a bit of research that the EOLYS Fluid needs to be replaced which it is booked in on Wednesday however,
how safe am I to drive it, would just be city driving, probably 60 miles? Won't be going 70mph for more than 10 minutes straight give or take.

Citroen DS3 1.6 HDI 2011

Thanks.
RichardW
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Re: P Level Low Error

Unread post by RichardW »

No problem at all - it only injects a very small amount when you fill up - there is no level sensor in the tank it's just an estimate, and comes on with quite a bit left.
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Paul-R
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Re: P Level Low Error

Unread post by Paul-R »

To be honest, that won't make any difference. Eolys is only added to the fuel after a fill-up. So, as long as you have enough fuel in the tank for a couple of days, then just drive normally.
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Inside every old person is a young person wondering what the hell happened.

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ne8ryan
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Joined: 14 Jan 2025, 12:20

Re: P Level Low Error

Unread post by ne8ryan »

Paul-R wrote: 03 Mar 2025, 16:28 To be honest, that won't make any difference. Eolys is only added to the fuel after a fill-up. So, as long as you have enough fuel in the tank for a couple of days, then just drive normally.
I never knew that, I wonder how it knows when to add in new fuel, clever. Thanks!
RichardW wrote: 03 Mar 2025, 16:25 No problem at all - it only injects a very small amount when you fill up - there is no level sensor in the tank it's just an estimate, and comes on with quite a bit left.
Ahh that's excellent, it's booked in for Wednesday anyways so no more driving after today, got quoted £60 plus labour..

Thanks for all of the help.
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Paul-R
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Re: P Level Low Error

Unread post by Paul-R »

ne8ryan wrote: 03 Mar 2025, 18:03I never knew that, I wonder how it knows when to add in new fuel, clever. Thanks!
It used to be that every time you opened the fuel filler flap a magnet would activate a sensor which would then trigger the injection of the Eolys. The system didn't know how much fuel you had put in so would squirt in a high amount. Bad news if you only top up in dribs and drabs.

The system is cleverer now and I believe just checks to see if the fuel gauge has had a sudden increase after being switched off. If yes then the system has a much better idea of how much fuel has gone in and can add a more measured amount of Eolys.
As I get older I think a lot about the hereafter - I go into a room and then wonder what I'm here after.

Inside every old person is a young person wondering what the hell happened.

"Trying is the first step towards failure" ~ Homer J Simpson?
ne8ryan
Posts: 7
Joined: 14 Jan 2025, 12:20

Re: P Level Low Error

Unread post by ne8ryan »

Paul-R wrote: 03 Mar 2025, 18:43
ne8ryan wrote: 03 Mar 2025, 18:03I never knew that, I wonder how it knows when to add in new fuel, clever. Thanks!
It used to be that every time you opened the fuel filler flap a magnet would activate a sensor which would then trigger the injection of the Eolys. The system didn't know how much fuel you had put in so would squirt in a high amount. Bad news if you only top up in dribs and drabs.

The system is cleverer now and I believe just checks to see if the fuel gauge has had a sudden increase after being switched off. If yes then the system has a much better idea of how much fuel has gone in and can add a more measured amount of Eolys.
Ahh gotcha. Minimum amount I put in is £20 which normally equals to half a tank on the fuel guage, most I put in is £60 which is a full tank, how the maths add up, I'll never know but Costco fuel is decent quality.
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GiveMeABreak
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Re: P Level Low Error

Unread post by GiveMeABreak »

If the vehicle has a fuel flap sensor, this is only used to inform the engine ECU that fuel may have been added, and to start a fuel level calculation measurement. Some later systems don't bother with the fuel flap sensor now in any case and just do the fuel calculation measurement regardless.

It takes a reading when the engine is stopped and again when restarted - checks the difference and determines the amount of fuel and therefore the amount of Eolys to inject.
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