A Little Knowledge.................diagnostics/p0402 Egr Flow

[PICASSOCONVERT]

Is there a way to erase fault codes and turn off the engine warning light without diagnostic equipment? (Read on for the background).

 

Still content with my success at doing the "rear brake job" and a service at the end of last year on my 03 reg 2.2HDi manual estate, I was dismayed on Monday to get "Antipollution Fault" and the engine warning light on.

 

However, undaunted I read around the forum and thought "Maybe I can do diagnostics, too". So as a start I ordered a sub £10 fault reader which arrived today. I plugged it in and it tells me I have faults P1352 (which from what others have said I can disregard) and P0402 - EGR flow excessive, whic I cannot ignore.

 

Now my poor car has been largely idle or used only for really short journeys recently which means I get the chime and the service light at startup because of the low battery voltage. So, I wondered if the DPF was getting clogged up.

 

So, on Monday evening I did about 80 miles at a steady 70mph in third gear (so about 4,000RPM) along the A1 just to see if anything would go bang, fall off or catch fire. Apart from a reduced MPG, commensurate with the thrashing, everything was, and still is, fine. The car is running as well as ever.

 

However, tomorrow I will start to do some of the basic checks referred to in other threads to try and identify the problem.

 

It would be nice to be able to clear the faults and reset the engine warning light to "off" (to see if they reappear) but my cheap code reader will not carry out these functions, so is there any other way to do it without spending £75 on  a Lexia set up (the data from which I probably wouldn't understand anyway!).

 

Thanks for any advice.

 

David W

[psicobra]

My cheap ass Bluetooth code reader can also erase the fault codes maybe the software you are using does not support the function rather than the reader.

 

Psicobra

Edited March 6, 2014 by psicobra

[paul.h]

If the code reader does not work properly with the car, are you sure the read codes are correct ? If the fault is no longer present, possibly switching the ignition on and off a few times might clear the warning light.

 

I have read that a faulty egr valve may give a lot of soot from the exhaust on accelerating once the engine is warm (it should not work when cold), but having a dpf may prevent this being seen. Something easy to check is if the swirl valve actuator plastic joint at the passenger end of the cylinder head has broken.

 

On one of the C5 sections there is a pinned list of some members who are willing to help others with diagnostics, where are you located in case one is near you ?

[PICASSOCONVERT]

psicobra - thanks for the reply. The unit I bought (Memoscanner U480) is an integrated unit which just plugs in and displays messages, so there is no separate software.

 

paul.h - thanks for your reply. I agree there is always the possibility that a sub £10 piece of equipment may not work and the codes generated may be wrong. At least it was a cheap and easy exercise.

 

You are correct about the EGR/black smoke issue, which my wife's Clio suffered from and was easy to fix. However, the DPF probably does hide the evidence on our "superior" DPF-equipped C5's!

 

I replaced a broken swirl actuator plastic joint last year and it is still intact and moves as it should, so I think I'm OK on that one.

 

I will turn the ignition on and off a few times as you suggest to try and clear the warning light. I already tried disconnecting the battery, which (as I expected) had no effect. I don't think there is a member with Lexia near me but the little garage in the next village will probably clear the codes and the engine light for me.

 

I am now going to go re-read a few posts and draw together the best approach to checking what I can. I'll report back, probably early next week.

 

David W

[qman3428]

_{If you have low voltage from the battery that is known to throw up spurrious results.}

[PICASSOCONVERT]

A belated update.

 

Good news - my car is running well & I've done a few longer journeys this last week with overall 54mpg showing on the display over about 400 mainly motorway miles. Still got the anti-pollution message and engine warning light. Additionally, early last week I got the low diesel additive warning so added 3 litres of Mr Citroen's finest eyolus fluid, but of course I haven't been able to reset the counter.

 

However, I have bought Lexia from a UK supplier on a well-known auction site so once I get my old laptop running reliably on Windows XP I should be able to install it and start to learn how to use it. I recall that qman3428 (thanks for the low voltage post) did say it's no use having the diagnostics if you haven't got the knowledge to fix the problems (or words to that effect).

 

If I can reset the eyolus counter and clear the fault codes it will be a good start (especially as MOT is due by end of April. I can then see if any faults re-occur as they may have been caused by low battery voltage.

 

David W

[PICASSOCONVERT]

I've finally got Lexia running on my old laptop, with the help of Jay at jjdiagnostics just down the road in Luton. It's been interesting looking at the information Lexia can provide. It was worth the cost just to see on one screen that my Exclusive is "Top of the range"...................

 

So far I have failed to reset the DPF fluid counter and I suspect I may need a new ECU. This happened on my 2001 2.2HDi and it may be the same on my present car which is a 2003 2.2HDi. It is interesting to see that Lexia gives the recent DPF regeneration history - at least shows that regeneration is still tasking place. Also no recorded faults on the DPF system, which is good.

 

The EGR faults are still there, though with the following data against code P0400:

 

Engine speed 771rpm

Airflow reference value 235mg/stroke

EGR valve electrovalve open cycle ratio 94%

Inlet airflow 559mg/stroke

Actual airflow 12mm3/stroke

 

In main parameters:

 

EGR open cycle ratio 5%

EGR throttle valve cycle ratio 5%

 

Of course, I have no idea what all this means so I will be making a trip to the nearest independent Citroen garage for some advice!

 

Finally having read the error messages when I try to erase them Lexia says "communication error" and the errors remain. Is this just because my Lexia is (probably) of non-European provenance?

 

Any comments anyone?

 

David

[paul.h]

Using an EOBD reader to erase fault codes you need the ignition switch on but not the engine running - I do not know if you have tried this.

[PICASSOCONVERT]

Thanks for ther tip paul.h - you are correct (of course!). I had a final look around this morning and discovered a split in one end of the fabric covered rubber tube that connects to the EGR valve. I cut 1/4" off the split end and reattached it.

 

With the ignition on, but the engine not running I was able to erase the error codes so I have been driving around today with the engine management/service lights not lit.

 

The EGR problems now appear to be solved.

 

The only minor irritant is that the "Diesel additive at minimum level" error message comes up briefly on the central display for a few seconds a couple of minutes after starting the car. However, I can live with that.

 

The only other thing which I did (and hadn't heard of before) was to enter the amount of Eolyse fluid I had put into the car (in milligrammes) on one of the Lexia screens - the amount then showed as grammes. I made the assumption that 3 litres of fluid would be about 3000 grammes.

 

So, overall, Lexia has proved its worth and saved me a trip to a garage.

 

Next job MOT in a few weeks........................

 

David

[paul.h]

Best type of fix this, lots of initial worry but ends up no cost apart from the outlay for a tool you will use frequently. This link to a Rhodia safety data sheet for eolys DPX42 gives its density as 0.812 kg/litre at 15°C. So 3 litres is 2436 grammes at 15°C. http://www.google.co.uk/url?sa=t&rct=j&q=&esrc=s&frm=1&source=web&cd=2&ved=0CDcQFjAB&url=http%3A%2F%2Fwww.autobenex.cz%2Fcs%2Fdocument-to-download%3Fid%3D193&ei=ibQ9U_bQOcWqhAfk4ICYBw&usg=AFQjCNHuKGjzBTL6PIDmBokUsqnR350gNw&bvm=bv.64125504,d.ZG4

 

In the C5 Technical section Common Problems post it suggests to check the egr valve hose for splits if there are egr fault codes, and as an example I have now linked to this topic.

[PICASSOCONVERT]

Hello Paul

 

Thanks for working out the weight of the fluid. I over-estimated, but I reckon that by the time the 3 litres of fluid I put in are used up the car will be in the next world (and so might I for that matter!).

 

I had read the common problems post in the technical section and the information was spot on, thanks again.

 

David

[PICASSOCONVERT]

Pleased to report my old car got through its MOT yesterday with no problems so just the road fund licence to renew and should be good for another year.

 

David