[Bogdan1986]

Hello guys!

2 years ago, a a month after I bought my i30 (it was owned by someone else previously), I had a CEL with a P0404 code that was set while on a long road trip in the month of July, after driving 1000+ kms on the highway in one day. Since it was under warranty, I took it to the dealership and, after having the car for a couple of hours in their workshop, they said the EGR system was fine, and it's most likely caused by carbon deposits in the combustion chamber. They told me to start using diesel additives, to help clean the injectors etc. I did that, even though I was unhappy to spend more money on fueling, diesel cars are advertised as being cheap to run, after all. Anyway, using additives seemed to have helped, I didn't have another CEL for almost 2 years. I should maybe add that my job restricted me from using the car in the hottest months of 2017.
This year, since mid April, right when the weather started to become warmer, with temperatures above 20 C, I had the CEL on again, with P0404, AGAIN. It was accompanied by an almost imperceptible rough idle at start and acceleration hesitation at operating temperature. I took the EGR valve out, expecting to find it clogged with soot, but I was very surprised to see that it was actually pretty clean, it only had a thin layer of soot deposits. I cleaned it as best as I could with aerosol EGR cleaner and measured the resistance. It was 8 ohms, within spec. I replaced it, cleared the code and drove for about a week without any issues. I noticed that, during that time, the weather cooled down a little bit, with temperatures under 18 C.
Now, the next time the air temperature hit 20 C, the car started to hesitate a lot when accelerating and it even went into limp home mode a couple of times. I thought it was the Turbo's fault, as it gave no boost during limp home mode, but after some research, I found out that is what limping home does, it cuts off the Turbo and keeps the EGR closed at all times, also.
After a couple more hesitant drives, the CEL came on with the same P0404 code. I bought a more powerful diesel additive (at least that's what they advertised it as), dumped it in the tank following the instructions, and drove with the CEL on for a few more days. Because I had the MOT a few days ago, I cleared the code to shut the CEL off, went to the MOT in the morning, passed the test, and on the way home, just as the temperature gauge showed 20 C, the car went into limp mode and by the time I was home, the CEL came back on.

 I started to check other systems and found that one of the glow plugs is showing a resistance of over 100 ohms, while all the others showed only 1 ohm, so I ordered 4 new ones, plus a new camshaft sensor (as I understood the EGR and fuel systems, if this sensor goes bad, it can mess with them also and it doesn't always set a code for it). Once I change them, I will clear the code again and see what happens.

Something else that I learned yesterday, is that I can use the Torque app to create logs of the systems it can monitor with the ELM 327 OBDII bluetooth scan tool. So, during a drive today, I logged the EGR and other system monitors and found something weird: the EGR valve's lowest commanded position is 4.7% (even at idle and full load) and the EGR Error is at 0% in this situation. When it is commanded to open, it does so to max 94.9% and max 7.5% Error, but at mid values of commanded EGR, the Error can be -20% to, a few times, 99%. This must mean the valve is sticking, right? I didn't clean the pipes leading to and from it, because they looked like they also had just a thin layer of soot, but if someone thinks they might be clogged in a place that I can't see, I will take the whole intake apart and see if there's a blockage somewhere.

Does anyone know if I can check the EGR valve some other way? Is it possible to manually open it at idle without an expensive two way scan tool, to see if the engine stalls, which would mean the valve itself is operating normally?
Is it possible that the hot weather would affect the normal operation of the valve? I had no issues even in -15C weather, I drove a 5000 kms trip this winter without a problem, plus I moved 100kms away in February, made a lot of trips between the former and new homes. It all started after the outside temperatures exceeded 20C.
Oh yeah, fuel consumption increased with 1.3 l/100 km too, which is definitely not normal, as I also changed the winter tyres with summer ones.

Sorry for the long post, I want to be as precise as possible. Any help would be greatly appreciated.

[Dazzler]

Welcome.

That must be our longest 1st post ever. But that's not a problem.  Quite the reverse. The more info the better. Hope someone can help.

If I tried to write a post that long it would error out and I'd have to do it all again. 

Sounds very frustrating.  I wonder if a new diesel filter would help sort it. Limp home is often related to fuel filter issues. 

[Dazzler]

Anyone got any ideas? A new member who has given this much info deserves some help! 

[CraigB]

Bogdan has done more already than what I know of diesels, similar fault finding method as specified here P0404 OBD-II Trouble Code: Exhaust Gas Recirculation Circuit Range/Performance | YourMechanic Advice

The webpage does mention the EGR valve might open and close correctly though only has to have some slight sticking/jerking movement and that enough to set off the sensor.

[Bogdan1986]

Thanks, guys! I appreciate your help.

I replaced the fuel filter last year/25000 km ago and, from what I can gather on the internet and this forum, the filter problem was restricted to the EURO 4 i30 1.6 CRDi U engine, mine is a EURO 5 1.6 CRDi U2 engine.



I saw this video today and used it to manually command the EGR valve to open, with key in ignition but engine turned off. I monitored the sensor with the Torque app while doing so and, weirdly enough, the EGR desired position went from 4.7% to 0%. I expected it to go up to at least 95%, not down... I could hear the pindle moving inside as I was shorting the control. I must be missing something. Unless the EGR position sensor is broken.
I didn't have the courage to short the control while the engine was on, but that will be the next thing later today. I will also look for ways to check the wiring and compare the voltages I measure to what the spec ones are (I need to find these specs).
I will wait for the new glow plugs to arrive before I will take apart the intake, although at this point I don't see a reason to do that, the error code is strictly for the egr range/performance, it is not a flow code.
Oh well, I will go through the instructions CraigB shared and try anything I haven't already, see what I come up with.
Thanks again, will update if I find something new!

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[Dazzler]

Sorry there is not more we can do to help. Sounds like you are already way ahead of my ability to assess car faults.

Before you change the glow plugs make sure you read all the treads about it on here as if they are really tight it can be a nightmare getting the old ones out. From memory the two main things are to squirt WD40 or similar around them a day or two before and let it penetrate and remove them from a warm engine.

[Bogdan1986]

Thanks for the advice, Dazzler. I will make sure to take precautions when it comes to removing the old plugs, they've been in there for 6 years lol

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[tw2005]

I'm just going to dribble out and quote parts of what the manual says.

Glancing on what you say , why not just replace the EGR?


P0404 is set when EGR actuator is stuck.

•  EGR actuator stuck
•  EGR actuator component

[tw2005]

can  your scan tool display, AIR MASS PERCYLINDER" parameter ?

Check if "AIR MASS PERCYLINDER"l is 340mg/st ± 50mg/st without EEGR operation at warm idle (Electric EGR control valve 6% duty)

[tw2005]

Disconnect EGR actuator.

 Measure the resistance between power terminal and control terminal of EGR actuator (component side).

(4) Is EEGR actuator component resistance within the specification?

 ▶ Go to "2. Check EEGR actuator operation condition" as follows.
 

 ▶ Replace EEGR actuator and go to "Verification of Vehicle Repair".
 

 
 
2. Check EEGR actuator operation condition
(1) IG KEY "OFF", ENGINE "OFF"
(2) Check that MAFS is installed in correctly according to the direction of arrow on MAFS assy’.
(3) Check contamination of air cleaner filter.
(4) IG KEY "ON", ENGINE "ON".
(5) Let IDLE RPM last after warming engine up.
(6) Check the leakage of intake system(the leakage or damage of intercooler).
(7) Check that VGT operates correctly.( Check if vacuum operating state of VGT actuator is appropriate, if VGT diaphragm and unison ring are stuck.)
(8) Check that EEGR actuator does not operate.
( EEGR actuator turns "OFF" and 6% duty is outputted 1 min. after rapid acceleration. )
(9) Monitor signal voltage of MAFS when engine speed lasts at approx. 800RPM using Scantool.
(10) Check MAFS output signal at idle after rapid acceleration.(EEGR actuator duty 50%)

--------------------------------------------------------------------------------

Specification : When EEGR actuator does not operate (6%) at idle : 340mg/st ± 50 mg/st
When EEGR actuator operates(50%) at idle : 200mg/st ± 50 mg/st
 
 


--------------------------------------------------------------------------------

Secification : 7.3~ 8.8Ω (30°C)


 

[Dazzler]

Thanks Gerard. You've set such a high standard lately I've started expecting miracles! 

[Bogdan1986]

Thank you for the new ideas, tw2005!

I would like to avoid buying a new EGR valve, as they are pretty expensive. The cheapest aftermarket valve I could find was 250 euro, somewhere in Germany, the original one in a danish car parts shop is around 700 euro (almost as much as a brand new DPF). I checked the wiring and all the EGR valve pins with a multimeter and everything is within spec.
My scan tool can only display MAFS readings, unfortunately no fuel trim or airflow per cillynder...
At this point, diagnosing this problem is proving to be too exciting to just give up .
This morning, I took the valve and EGR cooler out. They seemed fine, but found that the valve was sticking a little bit when I operated the pintle using pliers.
I then tried to blow air through the cooler. I was surprised to realise that I could not do it, the cooler was clogged inside.
After using half of an aerosol EGR cleaner can with no real effect, I turned to the oven cleaner that I had in the kitchen. That stuff is the best carbon build up cleaner I have ever seen!
I cleaned the throttle with it also, then rinsed all the parts with a mix of wd40 and engine cleaner. Don't want oven cleaner ending up in the engine. The insides looked almost like new, and I could blow air through the cooler freely!
After I put everything back together, I monitored the EGR with the scantool while starting the car. This was the roughest start I have seen this car have, ever. EGR position values were erratic, and I thought the engine would stall, but after a few seconds it was operating normally while the EGR value went down to 4.7%.
I drove around a bit, got the engine to 90 C and the car felt good to drive. And then, the acceleration hesitation came back... I didn't get a CEL yet, but I am sure it will light up in the next few days.
Oh well, I won't give up yet. I am still waiting for the new glow plugs and I might take the intake manifold out and clean it some time soon, it looked sooty and who knows how much carbon build up it might have in the out of sight places. I'll have to buy a new gasket and more oven cleaner lol



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[tw2005]

Assuming this is U2 motor, I think the part is 284102A350 . Number is stamped on the top casing, you'd have to check.

$178 USD plus shipping from Korea or 152 EURO + freight, no idea what duties you have, brand new genuine @ KORAPS

I'm confused with Romania and Denmark in the profile

[Dazzler]

I'm confused with Romania and Denmark in the profile

A quick IP check says Bogdan is in Denmark, so maybe the Romanian flag is an error (unless you are a Romanian living in Denmark Bogdan?)

[tw2005]

I'm confused with Romania and Denmark in the profile

A quick IP check says Bogdan is in Denmark, so maybe the Romanian flag is an error (unless you are a Romanian living in Denmark Bogdan?)

You're really not retired but working for the FEDs, are'nt you DAZZ

[Dazzler]

I've still got my fingers in a lot of pies.. 

[tw2005]

I've still got my fingers in a lot of pies.. 

So long as it's not "American Pie"

[Bogdan1986]

Indeed, I am a romanian living in Denmark. Sorry for the confusion
The part number on the EGR valve is 284102A300, they have it on koraps for 10 bucks more, thanks tw2005!
I will write to them, see if they know how I can pay less import tax. From what I know, the danish customs taxes everything with 25% of the value, plus the postal office charges 20-25 euro for the service of calculating the tax lol.

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[tw2005]

284102A300,

i20 10- i30 09- CEED 09- RIO 12- SOUL 09- GeNuiNe EGR VALVE 284102A300 | eBay

Keep this in mind, + gasket, free delivery.

 I recently purchased 2 ball joints which worked out cheaper via Ebay than their own site which you would not expect given they  thieve at least 10%.

I think they may have marked on the box gift I'd have to find it to check

[adrek]

When reading this topic I may have missed something, but if you could attach graph on how EGR works while driving it would be awesome. I do not want to worry you but I had few cases where engine ECU was causing P0404. But to confirm it for you I need to see EGR graph.

[Bogdan1986]

Thanks again, tw2005. I found an aftermarket valve in Germany for 200 euro, shipment and tax included, and I can return it for free if I choose not to install it for whatever reason.

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[Bogdan1986]

Hello adrek. The thought that the problem is in the ECU started to bother me for a few days now... I do not know how to get obtain the graph, though.
Is it possible to do it with the cheap ELM 327 + Torque app that I have?

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[Bogdan1986]

When reading this topic I may have missed something, but if you could attach graph on how EGR works while driving it would be awesome. I do not want to worry you but I had few cases where engine ECU was causing P0404. But to confirm it for you I need to see EGR graph.

Apparently there's a plug in for the Torque Pro app that creates graphs of your car's sensors, called 'Realtime Charts for Torque Pro'. Did anyone use it before and can confirm it is accurate?
I think the outside temperature has an effect, I didn't have any problems when it was under 18C.
My research into this matter found a common EGR problem in some early 00's Volvos, caused by the ECU overheating. Some people on that forum had success with attaching a computer fan to it (somehow).


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[Skovsgaard]

Hi

I experience the same symptoms as you so well have described. My car workshop replaced my EGR valve and told me that should fix the problem - but the symptoms returned (when the temperature raised above 20 degrees)! So to take matters in to own hands (with no mechanical experience in that area) I bought a Bluetooth OBDII scanner from Bluedriver, hoping to get a more fully diagnostic of my vehicle. I discovered that in my case there is an correlation between AC ON/OFF and the EGR command. I have attached a graph showing the trends of the EGR Command (0-100%) and EGR Errror (-100 - 100%). The areas with high peaks are when the AC is OFF (delayed and bad motor acceleration) and the areas with small peaks are when the AC is ON (momentary and good motor acceleration).

@Bogdan1986, do you have the same experience with the AC?

@adrek, can you tell something from the attached graph?

Regards

[Bogdan1986]

Hi Skovsgaard!
I'm sorry you're having issues with your car, but I must say, I'm glad I don't feel like I'm crazy anymore.
Unfortunately, my AC doesn't work. Another thing I noticed when the temperature went up...
I did go to a shop to have the AC system serviced, they filled it with gas and dye, and said it was empty, so they suspect a leak. I was to contact them when the AC would show signs it doesn't work again. Ofcourse, a week later it wasn't cooling so well anymore, so I made an appointment with the same shop to find and fix the leak. The date: 12.06. So, I can't test the AC - EGR correlation until they are done with it.

However, I did notice a change in engine tone whenever I would engage or disengage the AC during the week it did work... So there could be a link.

I am curious what @adrek can interpret from the graph you shared!

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[adrek]

tomorrow I will add screenshot from GDS how EGR was working with faulty ECU (accidentally left my usb drive at work..). As for added above image, how long is this recording? 21 minutes? It's completely unreadable.. also what were other driving parameters (RPM, speed)?

[Dazzler]

Great to see relatively new members from different countries helping each other. 

[Skovsgaard]

Hi Bogdan1986

Thanks for your reply.

It will be interesting to see if you experience the same behavior with the AC as I do! 

[Skovsgaard]

Hi adrek

Thanks for your reply as well.

I agreed, the graph is not that good and yes it is from a 21 min recording.

I will make a better graph within the next days and add RPM, speed etc.

Looking forward to see the screenshot from GDS.

[adrek]

what is important - try to drive without sudden braking or acceleration when you problem occurs