My C5 Went Into Limp Mode

[Johndouglas]

Since last Friday night I've been towing my caravan to southern Spain.   Early on Monday morning, only about 20 miles into that day's travel I was pulling up a hill.   Suddenly the EML flashed on together with an antipollution fault, followed by a speed control fault.   The car also went into limp mode.   With some difficulty I got to the top of the hill in first gear where I was able to pull into a slip road.   I switched off for a few minutes then tried the starter again.   The engine readily started but with the EML still showing.   Fortunately I had my Autel 509 with me so I connected it.   It was showing a fault code P0093.   I erased the code and with a trembling hand tried the starter again.   The engine started without any lights showing and with some trepidation, moved off in first gear.   I got up to the towing maximum and the engine seemed fine.   In fact it behaved itself for the rest of the journey -  another 280 miles.   Just this afternoon I connected up the code reader again and no faults were stored.   So why did it scare the life out of me?

[paul.h]

An internet search suggests a few things for P0093. Low fuel pressure, on a C4 the cure seemed to be a new fuel filter. Have you got some dodgy fuel ?

[Johndouglas]

. Have you got some dodgy fuel ?

I did think about that myself.   I filled up just before I stopped for the night and in addition to the limp mode event, the performance and economy was less than good.    During the afternoon I topped up the tank and I think performance improved.

[coastline taxis]

The following is just what i think and i have nothing to back it up with. the c5 has a adaptive drive cycle where the ecu learns your driving style and alters/adjusts things to suit your driving style and legal emmisions. so for the last few months your car has done mostly town driving at english temperatures using english fuel. then you put a caravan on the back and head of down the motorway.to hotter climates which is totally alien to what the ecu has learnt. we o.ften get this on the taxis where they spend months round the town then go off down the country and the management light comes on, Now remember we have experience also free labour and a abundence of spare parts and we can never find out what puts the light on. what we have done in the past is before a car heads of on a long distance ( i regulary take one to spijkenesse in holland) we do a bsi reset and the car then learns the driving style on the motorway and dosnt put the light on but what it does do is when the car is back to work round the town it then puts the engine light on and again theres no faults to find. this happens on whatever c5 i take. Like i say i have nothing to back this up with at all just a opinion

[Vin1100]

Have you got some dodgy fuel ?, this makes me wonder, would it pay to use the same fuel company to fill your car. I know that some big chains mix their fuel to alter strength. I proved this a fee years ago on a friends audi... so just wondering if the same would apply on diesel??

[Johndouglas]

Since the trouble hasn't reoccurred then Yes - I think I got some dodgy fuel.    Here in Spain most filling stations are supplied by either Repsol and Campsa.

[JM53 BEL]

I thing i would definately do is replace Fuel Filter, i was gettimg similer issue with my car every now and then it would give a wee cough then DPF system fault came up on display putting EML on till one day it came up and went in to limp mode and wouldnt clear, turned out the fuel filter was choked which was causing fuel pressure to drop!

[Johndouglas]

I thing i would definately do is replace Fuel Filter,

The car has only done around 2000 miles since the last change, - but you're right!   A blocked fuel filter could have been the cause.

Also there's a new theory that's being bandied about regarding bio-diesel - which all pump diesel now contains.   Apparently it's causing fuel filters to block rather like waxing would do..

[JM53 BEL]

I have heard the HDI engines are suffering the worste with this bio fuel issue, they dont like bio diesel as you say there is a waxing thing, bit like when cooking oil goes that sludge lard way when it cools down after cooking if you know what i mean

[coastline taxis]

was talking to the lads in town center citroen parts the other day and they were saying that the sales of fuel filters is right up the last couple of months