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General Engine Dysfunction

27K views 25 replies 5 participants last post by  thetapeworm 
#1 ·
Mainly posting for future searches on this as it seems like this isn't discussed much. I know there is another topic where its mentioned but there doesn't seem to be a definitive answer.

My wife's diesel is due a service but after putting fuel in it suddenly came up with the message below. An ODB2 check reports no logged faults and the engine management warning light in the dash isn't lit.

Faulty Engine Control System:

Avoid using your vehicle until it has been serviced by a Citroën dealership.

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I was hoping to get the car serviced at a local specialist rather than a main dealer (Leeds) but nobody seems to be able to recommend one.

In light of this message I'm now feeling like I'll have to go to the dealer... but is this their cunning plan?
 

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#4 ·
Being a little bit cynical, I would use the car a time or two just to make sure the fault message keeps appearing.
I have had erroneous lights coming on occasionally over the years and then clearing never to be seen again,
Previous citroens used to store fault codes for around 10 starts and then clear.My cactus currently loves to tell me that I have an ABS fault. This always shows after I have altered my tyre pressures and reset the TPMS.Previous C3 twice told me the MAF was faulty. Car is still running with 140000 miles still with original sensor.
The more sensors and "clever" the cars get the more sensors to go wrong, ever seen predictive text in action😁
 
#5 ·
After my wife's initial panic phone call from the garage forecourt the car has been in regular use, been refuelled again and seems absolutely normal in all respects. The error on screen (and the app) won't go away and my fairly limited OBD2 reader can't see any issues, a code reset has no effect so presumably the Citroën kit handles this.

I know I can reset the service light and am tempted to see if it also makes this go away but I'd prefer not to. Currently planning a non Citroën service & brake pads and if this persists to go to them with just this so my wallet isn't too upset.
 
#6 ·
Service completed today (non-Citroen) so that's out of the way at least.

Called the local dealer (Evans Halshaw) to enquire about the "General Engine Dysfunction" message to be told it could mean anything and that I need to book it in for a £50 diagnostics check, the earliest date being in May.

I don't see what alternative I have as presumably it has to go on a Citroen diagnostics machine given nothing is being picked up via the regular OBD2 scanner and, based on what I've read on here, it might need a software update to fix this. Presumably this would cost me on top of the £50 given the car is now 3 years old?

This is why I choose to drive old cars :)
 
#8 ·
I have had a similar fault in our C4 Picasso, and many others on the C4 forum have had this issue. The issue here is it is not clear if the fault is with the EOLYS pump or the Adblue pump. If it is the Adblue pump, the agent solution will most likely be a new Adblue tank, as it appears the pump is not available separately. Sorry, but it is likely to be expensive.
 
#9 ·
Thanks for your reply, even if it's potentially bad news :)

Seems somewhat ridiculous for a part like this to fail after 28,000 miles, the thing that's got me wondering is why it happened right after she put diesel in it. No issue, diesel in, error codes, the timing seems incredibly suspect.
 
#10 ·
Ran some logging with FAP on Sunday, if the app is to be believed the car has used 5ml of AdBlue in a month, we've done a fair amount of miles / journeys in that time so something is clearly afoot.

I need to check fuses and have a bit more of a poke around, I'm not quite defeated yet but the more time goes on the more I worry.

Still loathed to take it to Citroen but would happily drive to a specialist outside of the Yorkshire area if anyone has solid recommendations, I just don't want to be paying for silly diagnostics and then a fix by numbers solution where they essentially rebuild the entire car using expensive off the shelf bits.
 
#11 ·


Screen shot from FAP Lite showing supposed additive levels between the end of April and today.

I put 5L in at the end of last year but I'm unsure what normal consumption rates are, it's using some though apparently.

Oddly the urea warning light came on this morning with the associated 1500 mile message on screen so something is happening, somewhere.

Edit: 10L of AdBlue just added so it was definitely in need of some.

FAP lite AdBlue capacity levels didn't update though and I know it pulls this from the levels the ECU is reading, the Urea light and associated warning went off so the car knew...

It had a 3 year service last month and I thought that would include AdBlue so something else for me to check.

I spoke to a local diagnostics / mapping chap who, quite honestly, said he'd rather not get involved based on previous experience of similar issues on Citroëns :lol:

And still not 30k on the clock.
 

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#12 ·
thetapeworm said:
It had a 3 year service last month and I thought that would include AdBlue so something else for me to check.
My experience is that AdBlue top ups are not part of routine servicing unless you ask for it (and at around £40+ for it to be done in the service it is also expensive). My local dealer always asks if I want it done or not when I book it in.
 
#13 ·
VinceMarsters said:
thetapeworm said:
It had a 3 year service last month and I thought that would include AdBlue so something else for me to check.
My experience is that AdBlue top ups are not part of routine servicing unless you ask for it (and at around £40+ for it to be done in the service it is also expensive). My local dealer always asks if I want it done or not when I book it in.
Cheers, that seems to be the same policy my independent has, I see Citroen also do it as an extra for £19.99 for a 10L fill.

I managed to find a decent screw-on nipple and tubing to get the 10L in, it's not in the nicest place to top up in the Cactus, I know they are made to a budget but I'd gladly have paid £100 more for the car to have a filler neck in a nice location :)

On the error code front I've diverted back on to the filler cap sensor again, probably incorrectly, as it first happened when my wife refueled... the only issue being I can't see if the Cactus has a cap sensor :lol:
 
#14 ·
I still think there is confusion here. The sensor in the cap is nothing to do with the Adblue system, it is to do with charging EOLYS fluid to the fuel tank. I'm sorry to say that if you are using too little Adblue that your issue is with the Adblue pump' which is a well-known issue. I still suspect you will need a new Adblue tank.
 
#15 ·
routemaster1 said:
I still think there is confusion here. The sensor in the cap is nothing to do with the Adblue system, it is to do with charging EOLYS fluid to the fuel tank. I'm sorry to say that if you are using too little Adblue that your issue is with the Adblue pump' which is a well-known issue. I still suspect you will need a new Adblue tank.
Thanks.

I went down the cap path because the issue started immediately after a refuel, I just wanted to rule this out - someone has tested their car with no cap on for me (like I already did) and found it didn't throw up any messages so a dead end I've stopped chasing now :)

As far as AdBlue consumption goes it's using it and seemingly at a reasonable rate, FAP just isn't showing it correctly for some reason, when I put 10L in recently the readings in FAP never changed but the car knew it was there and turned off the Urea light and the message on screen about needing a refill. I haven't rechecked with FAP since but 24 hours later it still hadn't updated AdBlue levels when connected.

I've read about the pump issues and the need to replace the whole tank as it's an integral part of it (stupidly), I just can't get my head around anything like this failing at 28k and given it's still using AdBlue I still hold on to the hope that it's a sensor.

Ultimately, given my independent diagnostics company refuse to look at any more Citroens, I'm going to have to suck it up and go to the main dealer, I just want to avoid their "fix by replacing the entire system" methods, seems impossible though.
 
#16 ·
Just to add, I plugged the reader and opened up FAP again last night, the AdBlue levels being reported still haven't moved despite me having put the 10L some time ago.

Not sure if that's a FAP issue or that the sensor is goosed but as mentioned above it certainly knew when I'd filled up again after the warning it was getting low.
 
#17 ·
thetapeworm said:
Just to add, I plugged the reader and opened up FAP again last night, the AdBlue levels being reported still haven't moved despite me having put the 10L some time ago.

Not sure if that's a FAP issue or that the sensor is goosed but as mentioned above it certainly knew when I'd filled up again after the warning it was getting low.
Adblue does not affect FAP, that is what the EOLYS does. Adblue is injected somewhere in the exhaust system to reduce nitrogen oxide levels. The Adblue tank holds about 17L and lasts ~12,000 miles so it should use ~1.5 L per 1000 miles.
 
#18 ·
routemaster1 said:
thetapeworm said:
Just to add, I plugged the reader and opened up FAP again last night, the AdBlue levels being reported still haven't moved despite me having put the 10L some time ago.

Not sure if that's a FAP issue or that the sensor is goosed but as mentioned above it certainly knew when I'd filled up again after the warning it was getting low.
Adblue does not affect FAP, that is what the EOLYS does. Adblue is injected somewhere in the exhaust system to reduce nitrogen oxide levels. The Adblue tank holds about 17L and lasts ~12,000 miles so it should use ~1.5 L per 1000 miles.
Cheers, as you can see this stuff is all new to me, I need to do more reading on this.
 
#19 ·
thetapeworm said:
routemaster1 said:
thetapeworm said:
Just to add, I plugged the reader and opened up FAP again last night, the AdBlue levels being reported still haven't moved despite me having put the 10L some time ago.

Not sure if that's a FAP issue or that the sensor is goosed but as mentioned above it certainly knew when I'd filled up again after the warning it was getting low.
Adblue does not affect FAP, that is what the EOLYS does. Adblue is injected somewhere in the exhaust system to reduce nitrogen oxide levels. The Adblue tank holds about 17L and lasts ~12,000 miles so it should use ~1.5 L per 1000 miles.
Cheers, as you can see this stuff is all new to me, I need to do more reading on this.
I'm not surprised that people have difficulty getting to grips with this. When Adblue first appeared, the internet was full of talk of how Adblue would mean the end of EOLYS. Even Honest John wrote an article which was a total pile of rubbish. Having had 5 Citroens with EOLYS (and never had a problem), and being a member of the C4 forum for about 14 years, I have seen it all.

Here is a copy of the post I made on the C4 site.

Right, enough of this confusion. There is a load of rubbish written on the internet concerning Adblue and EOLYS, including much twaddle written by motoring journalists who obviously don't understand how cars work. I have read many times that Adblue replaces EOLYS., so I consulted the head technician and the parts manager at my local Citroen agent, and they both confirm that Adblue fitted cars also have the EOLYS system.

The Adblue is carried in a tank fitted near the fuel tank. It is injected into the exhaust system to convert nitrogen oxides. The tank has a capacity of ~17 litres, and will last for 12-14000 miles. It is easy, cheap and safe to top up the system at home. The filler is below the boot floor on C4Ps and below the offside 3rd row seat in C4GPs, although possibly later cars have the filler next to the diesel filler. There will be an alarm and a countdown displayed when the level gets low. Failure to top up will result in the car failing to start. A fill of 5L should be enough for the system to register and reset. THE Adblue HAS NO EFFECT ON THE DPF SYSTEM. (DPF = Diesel particle filter)

The EOLYS tank/pouch is under the car near the fuel tank. The EOLYS is a solution of curium compounds, and it is injected into the fuel. It then helps to catalytically oxidise the carbon particles in the DPF to carbon dioxide. The EOLYS is supposed to last 85-90000 miles, but our C3 has covered 115000 miles without topping up. There may be an alarm if the fluid pouch is empty, but I have never seen it. Failure of the system or running out of fluid may well result in the DPF clogging. I wouldn't want to change the fluid myself, but many have, but the counter must be reset using Lexia/Diagbox. Failure to reset will result in no fluid being injected and the risk of the DPF blocking.

I really hope I have explained everything clearly!
 
#21 ·
My new car (2014) has error P2202 which indicates NOX sensor circuit low, bank one. What circuit is it measuring? Amps?? Will other components in this system affect the sensor and cause the fault code, such as pump not working, or reduced flow ? Or does it purely point to the sensor itself?
If the pump is not working, then surely it wont be pulling amps and therefore causing the low circuit??
I'm not a motor mechanic or electrician so forgive my ignorance.
 
#22 ·
jpgreenwood said:
My new car (2014) has error P2202 which indicates NOX sensor circuit low, bank one. What circuit is it measuring? Amps?? Will other components in this system affect the sensor and cause the fault code, such as pump not working, or reduced flow ? Or does it purely point to the sensor itself?
If the pump is not working, then surely it wont be pulling amps and therefore causing the low circuit??
I'm not a motor mechanic or electrician so forgive my ignorance.
It'll be measuring voltage, if it's triggered a P2202 then chances are it's got a low reading, "bank one" is a slight red herring as we'll only have one bank on our cars, bank two would come into play on a V6 or a V8 type layout IIRC. Bank one is the side with cylinder #1 on it but obviously all of our cylinders are on the same side.

Unsure what your mileage is but the sensor could just be caked up with soot, I doubt it relates to any other systems in this case. If it was me I'd probably remove the sensor from the exhaust and inspect it, maybe blast with carb cleaner and see if that helps, if it doesn't then the sensor may need replacing or it could be an issue further along the wiring to it that's preventing the ECM getting the signals it expects, I believe the sensor on the Cactus has a little circuit board on the wiring that's in its own box and sometimes this gets faulty.
 
#23 ·
Citroen has replaced the sensor and the garage I bought the car from has put a new battery on it and put half a tank of diesel in for me as its a 80 mile round trip. I also got a courtesy car, and the cactus has had 2 recalls checked for the catalytic converter and the adblue tank lid.
Car has just less than 43k on the clock. Hopefully that is the end of my troubles and I can now start to enjoy my new car.
 
#24 ·
So I finally had chance to try and move this one forward and have an update.

I found a local diagnostics place with Lexia (Auto Diagnostic Services in Leeds) and booked the car in with them. They carried out some initial checks and, in their words, "found faults in the engine ECU for additive ECU and also AdBlue leak".

Further checks in the additive ECU side found that there was a pressure fault in the additive circuit, excessive pressure.

They primed the AdBlue and the EOLYS systems and this cleared the AdBlue fault but the other remained.

Additive system blockage suspected (they've had three cars in this year with the same issue), either additive pipe or mechanical injector on fuel tank.

Pressure test found the injector would only open at 600 millibars. Cleaned pipe & injector and then found opening pressure to be 175 millibars which is supposed to be the right pressure.

After a couple of road tests the fault cleared.

As mentioned above ours was the fourth car with this issue that they've seen, this was great for me as one of the other customers had to pay for all the diagnostics carried out to isolate the problem, but it could be indicative of a problem that's likely to affect more people. It first came around for us at 28,000 miles following nothing more than a routine diesel top up (which would have then caused the system to do it's thing).

They suggest that if the problem occurs again it could mean we need a complete fuel tank or sender unit depending on which bit has the mechanical additive injector in it.

To me this sounds like a design flaw that needs addressing by Citroen but I know they don't always work like that, as it's something that doesn't seem to relate to how you drive or what you do then it could be a bit of a lottery as to if / when it happens :(
 
#25 ·
Sadly the issue appears to be back, same onset as before, all fine, no sign of any issues, put some diesel in (the warning light had just come on) and on starting the car...

"Engine fault: Have the vehicle repaired" along with the service light.

As before car feels absolutely fine, sounds OK etc so I guess I'll be ringing the diagnostics place I used last time in the hope they've learnt even more about this since last time.
 
#26 ·
I forgot to update this again, I went back to the same garage as I used previously, it was an odd experience involving a botched service and the car coming back with the fault despite spending considerably more on enhanced diagnostics but when it went back for the service issue sorting it came back with no faults and has been fine since.

The low speed engine fan sensor borked around the same time which added some confusion but I sorted that.
 
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