EGR Valve Self Test Procedure (IDE00242)- P046C?

[Cuiken]

One more thought: if you have a carista or some other decent OBD dongle I would set up a dashboard to graph IDE07756 and IDE07757 either from Car Scanner (iOS, Android) or Torque (Android). That way you could see them on the phone during driving and maybe catch if there’s any discrepancies, no good to run VCDS all the time. If this sounds like something you would like to pursue, I can help with iOS settings, have to rely on @mmi regarding Android . No guarantees though - we know the required settings for CXEB but can’t be sure same settings work with your ECU software version as it’s different

Thanks, I don't have a Carista but they don't seem expensive (£34.99 on Amazon) so I might take the plunge. I have an IOS phone so I guess the App (as listed in the app store) would be Car Scanner ELM OBD2? Is it expensive to use (once you factor in the required in-app purchases)?

Ta!

Cuiken

 

[n10n]

Thanks, I don't have a Carista but they don't seem expensive (£34.99 on Amazon) so I might take the plunge. I have an IOS phone so I guess the App (as listed in the app store) would be Car Scanner ELM OBD2? Is it expensive to use (once you factor in the required in-app purchases)?

Ta!

Cuiken

Yes, that's the one: ‎Car Scanner ELM OBD2

Not expensive to use. One time payment through in-app purchases, this is what it shows in my Finnish appstore:

I purchased high price version early 2022 and it is a perpetual license - no subscriptions or further payments and no ads.

Car Scanner FAQ – Car Scanner ELM OBD2

www.carscanner.info

Please hold your horses for a bit - I'll test little bit later today to make sure we are able to read those IDEs in the CarScanner, should be ok but let's verify. And I still can't guarantee it works with your engine software version as I have no way to test that. But at least I can show how it looks like on another CXEB so no surprises on that front.

 

[n10n]

I'll test little bit later today to make sure we are for sure able to read those IDEs in the CarScanner

Ok looks good to me. I recorded couple of minutes drive with engine warmed a bit so that we get negative EGR position readings. I think I got the scaling like it would be in VCDS, not that it really matters much as the intention is to compare the two graphs. But anyway.

 

[coopso]

I've a CXEB engine (I believe), and a Carista. Would be interested in monitoring my EGR as a preventative measure. No issues at this moment and I'd like to keep it that way... Apologies if I've misunderstood but if you're willing to help me set that up, it would be great.

 

[n10n]

I've a CXEB engine (I believe), and a Carista. Would be interested in monitoring my EGR as a preventative measure. No issues at this moment and I'd like to keep it that way... Apologies if I've misunderstood but if you're willing to help me set that up, it would be great.

PM’d. If it’s 204 T6 it’s CXEB.

 

[coopso]

Generally patterns match except occasionally Im seeing noise like this.

 

[n10n]

That noise looks to be sitting around EGR closed position and might indicate partial clogging or difficulties of closing the valve fully. I would adjust the graph limits from -10 to 10 so that you see the noise better. Also maybe try Car Scanner Data recording feature to capture some of that in a file - I haven't personally used that feature so I'm not sure how well that works.

You mentioned you have no issues at the moment but have you had any EGR fault codes in the past? If not, I would maybe just keep an eye on this and try to identify if there's changes with the time or differences in a cold / warm morning etc. There will most likely be EGR flow rate fault codes eventually but it might take quite a while before it becomes an issue. That said, I don't know if there's too many cases of recorded data about early EGR symptoms around - probably the most are only diagnosed after there already has been fault codes. So, I don't know how early these symptoms could be.

 

[n10n]

That noise looks to be sitting around EGR closed position and might indicate partial clogging or difficulties of closing the valve fully. I would adjust the graph limits from -10 to 10 so that you see the noise better. Also maybe try Car Scanner Data recording feature to capture some of that in a file - I haven't personally used that feature so I'm not sure how well that works.

You mentioned you have no issues at the moment but have you had any EGR fault codes in the past? If not, I would maybe just keep an eye on this and try to identify if there's changes with the time or differences in a cold / warm morning etc. There will most likely be EGR flow rate fault codes eventually but it might take quite a while before it becomes an issue. That said, I don't know if there's too many cases of recorded data around early EGR symptoms around - probably the most are only diagnosed after there already has been fault codes. So, I don't know how early these symptoms could be.

Warning - pure speculation ahead

Healthy EGR's seem to sit at 0 both on specified and actual value on closed position. Also, we know EGR position is mostly negative in normal operating conditions. Now, both @Cuiken and @coopso EGR's show specified value on at +5 - +6%. However, @Cuiken samples had hard time reaching 0 whereas @coopso samples seem to oblige and reach the specified value, albeit with noisy response.

Summing above together, my thinking is that when ECU detects the valve has difficulties in closing it adjusts the specified position further on positive side to apply little bit of force to better close the valve. Eventually the valve can't close anymore despite of the added force and then there will be fault codes.

 

[n10n]

@coopso Could you please add yet another custom sensor with the following and see if it is anything other than zero especially when you see the ripple in IDE07757:

Name: IDE07758
Command: 22446E
Header: 7E0
Formula: ((A*256)+B)*0.01
Unit: %

This is something called "Exhaust recirc.valve 1 bank 1: posit.feedback - Offset closed,0.00, %" - it would be interesting to see if this would flag if / when ECU has noticed something with EGR closing and thus offsets the closed position in an attempt to block the valve better?

Perhaps just replace IDE07756 graph with this for a while so it would be easy to see while driving?

Thanks!

 

[coopso]

That noise looks to be sitting around EGR closed position and might indicate partial clogging or difficulties of closing the valve fully. I would adjust the graph limits from -10 to 10 so that you see the noise better. Also maybe try Car Scanner Data recording feature to capture some of that in a file - I haven't personally used that feature so I'm not sure how well that works.

You mentioned you have no issues at the moment but have you had any EGR fault codes in the past? If not, I would maybe just keep an eye on this and try to identify if there's changes with the time or differences in a cold / warm morning etc. There will most likely be EGR flow rate fault codes eventually but it might take quite a while before it becomes an issue. That said, I don't know if there's too many cases of recorded data about early EGR symptoms around - probably the most are only diagnosed after there already has been fault codes. So, I don't know how early these symptoms could be.

Will do, yes. Interesting findings. I only noticed this noise about an hour into a 60-65 mph motorway drive (typical of the driving this car has done it's whole life).
No I don't recall any EGR faults, certainly nothing on the dash, in the 2.5 years I've owned it. Glad I can keep an eye on things now.

 

[coopso]

@coopso Could you please add yet another custom sensor with the following and see if it is anything other than zero especially when you see the ripple in IDE07757:

Name: IDE07758
Command: 22446E
Header: 7E0
Formula: ((A*256)+B)*0.01
Unit: %

This is something called "Exhaust recirc.valve 1 bank 1: posit.feedback - Offset closed,0.00, %" - it would be interesting to see if this would flag if / when ECU has noticed something with EGR closing and thus offsets the closed position in an attempt to block the valve better?

Perhaps just replace IDE07756 graph with this for a while so it would be easy to see while driving?

Thanks!

Will do. Car will next be used for a motorway journey again this weekend coming.

 

[n10n]

Will do, yes. Interesting findings. I only noticed this noise about an hour into a 60-65 mph motorway drive (typical of the driving this car has done it's whole life).
No I don't recall any EGR faults, certainly nothing on the dash, in the 2.5 years I've owned it. Glad I can keep an eye on things now.

Of your five screenshots, four are 16:15 - 16:37. In these, both the specified and actual egr valve position are flat - I believe this is indicative of a regeneration taking place. Would also explain noticing the ripples only about an hour into the drive.

 

[Cuiken]

Ok looks good to me. I recorded couple of minutes drive with engine warmed a bit so that we get negative EGR position readings. I think I got the scaling like it would be in VCDS, not that it really matters much as the intention is to compare the two graphs. But anyway.

@n10n,

Sorry, been away camping in the van for a few days so not keeping up (using the van rather than fixing it )

This looks really useful I'll pick one up next pay day (rooked after the EGR replacement). Definitely easier than lugging a laptop and connector around all the time.

Really appreciate all your help with this.

 

[n10n]

Generally patterns match except occasionally Im seeing noise like this.

For reference, this is what mine looks like during regeneration.

IDE07756/IDE07757 stay little bit on the negative side and there is minor ripple. Please note the vertical scale is -5 .. 5, the ripples are practically invisible if the full scale -120 .. 120 is used.

The graph is not produced from CarScanner - but I think somewhat similar graphs could be done with CarScanner data recording and graphing out in Excel or some other tool.

 

[n10n]

Interesting small observation from today: I use coasting all the time, so basically idling in downhills etc. Then, EGR sits around +30%. But if I tap the break to engage gear, EGR goes to near zero (-0.8% in my case).

So… if @coopso is using coasting as well maybe above helps to see the ripple on will instead of waiting for regen.

 

[coopso]

Interesting small observation from today: I use coasting all the time, so basically idling in downhills etc. Then, EGR sits around +30%. But if I tap the break to engage gear, EGR goes to near zero (-0.8% in my case).

So… if @coopso is using coasting as well maybe above helps to see the ripple on will instead of waiting for regen.

Yes, I coast all the time

Long journey on Saturday. The additional sensor stayed at 0 for the entire 3 hour journey. I took a couple of screenshots on the drive. Think I'll revert to the other view so I can monitor the requested position vs actual position.

 

[n10n]

Yes, I coast all the time

Long journey on Saturday. The additional sensor stayed at 0 for the entire 3 hour journey. I took a couple of screenshots on the drive. Think I'll revert to the other view so I can monitor the requested position vs actual position.

View attachment 215102

View attachment 215103

Thank you for taking the time to test!

Unfortunately the theory about the offset apparently did not play out, although these screenshots just show around 0 hovering rather than +5% earlier. Still, I think you would have noticed if there was any life in the offset graph.

 

[mmi]

Also, we know EGR position is mostly negative in normal operating conditions.

Yes, or perhaps not... a snapshot from tonight's run... winter is obviously coming

Interesting small observation from today: I use coasting all the time, so basically idling in downhills etc. Then, EGR sits around +30%. But if I tap the break to engage gear, EGR goes to near zero (-0.8% in my case).

Also seen in the graph above (I do not use coasting)

 

[n10n]

Yes, or perhaps not... a snapshot from tonight's run... winter is obviously coming

View attachment 216022

Already now over 50% of the trip cooler is not used. Another month and it will be close to 100% - maybe this helps cooler to last longer or changes the fault probability towards valve sticking rather than a blocked / leaking cooler.

Intriguing!

 

[n10n]

Also seen in the graph above (I do not use coasting)

Right, this behavior has nothing to do with coasting really. Just idling vs engine braking. I just happened to notice it in the context of coasting and it was totally repeatable - therefore an easy way to get EGR to a desired position for observations during a drive.