Lack of Air through EGR fault message by JohnDotCom


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JohnDotCom
I have recently had the engine management warning light come on a few times.
No ill effects can be heard/seen/measured and I have been clearing the warning until it returns again.
Now this last couple of occasions I have read the fault code, and it is saying insufficient airflow through EGR (Exhaust Gas Recirculation Valve)...................the problem?
I have the EGR bypassed and it has no leaks or any other visible problems, on removing no blockages visible or in pipes.
Bit stuck now, any ideas or advice please? :mad1:
I do have a new EGR but didn't want to fit as I thought that would be even less throughput.
John

"My lovely car now sold onto a very happy new owner.
I still love this marque and I will still be around, preferred selling to breaking, as a great runner and performer"

Posted 07 Feb 2014, 15:25 #1 

User avatar
Duncan
The system doesn't measure the airflow through the EGR directly. It must be looking for some other change. Now oddly, blocking it off doesn't normally trigger the fault, even though there's no flow at all.

Unfortunately I don't know what it's looking at. I doubt it's a MAF (Mass Air Flow Sensor) thing as the MAFs going faulty don't cause a fault until they are really bad. There isn't a lambda sensor, so it can't be complaining that it's not seeing the change as the valve opens and closes. Maybe it's expecting to see a change in the MAP sensor, but that still doesn't explain why removing the EGR doesn't normally cause it.

Do you have a Synergy? Does it make a difference if you change the settings?

I am just guessing here.
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Posted 07 Feb 2014, 19:23 #2 

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Duncan
Oh, and another question. Is this a fault code read with a T4 (Testbook version 4.Computer Diagnostic System)? Some of the generic readers can give misleading codes.
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Posted 07 Feb 2014, 19:24 #3 

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Duncan
Just had a read of the manual. The system does use the MAF to check the EGR flow. So maybe a combination of your EGR bypass, and an out of spec MAF is pushing it into the fault code zone?
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Posted 07 Feb 2014, 19:27 #4 

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Arctic
(Trader)
Hi Duncan.
Could the MAP sensor being clogged up with gunk give this fault or reading ?

MAP in various stages of being clogged up before all were cleaned with carb cleaner and or electric cleaner
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Posted 08 Feb 2014, 03:30 #5 

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Duncan
Yes Steve, it's possible. The Manual says it uses the MAF, but it must do a comparison between MAF and MAP as part of it.
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Posted 08 Feb 2014, 08:46 #6 

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Arctic
(Trader)
So it could well be worth removing it give it a clean, replace and see if it make any difference, as you can see i have three which are now clean ;) along with three manifolds and EGR, ready for when a member would like to have them changed, i do mine twice a year a bit OTT i know but i am like that, :em: but yes i would get it taken off and clean it, Arctic. :thumbsup:
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Posted 08 Feb 2014, 12:34 #7 

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JohnDotCom
Thank you both for your comments.
Duncan will respond to questions ASAP. Unfortunately gone down a bit crock again.
Didn't want to think I wasn't responding or being very grateful.
Will try to get into writing mode proper in next few days if I can, thanks.
Until then"...........................
John

"My lovely car now sold onto a very happy new owner.
I still love this marque and I will still be around, preferred selling to breaking, as a great runner and performer"

Posted 08 Feb 2014, 20:40 #8 


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