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jonnyboy54321
Member Since: 14 Jul 2012
Location: surrey
Posts: 114
  
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| Can a faulty EGR cause systems fault/special programs off? |
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Evening all, have done loads of searching.
D3 57plate 127k miles. Replaced EGR's a couple of months ago as was down on power. On monday night I went to jump in and hoof out for some needed diesel due to the panic buying. The car had been parked on the drive all day after use, only thing of note was I'd had door open for an hour or so while i worked on another car. Immediately I jumped in, started up, got the Systems Fault/Special Programs off warning. Car was in limp, drove it around a bit and it picked back up, all was well so I decided to carry on for fuel. No EML was on, I didn't have my IID BT with me at the time. Thankfully she started ok and I got out of the queue, came home.
Nest day, did a plugin, showed an EGR fault, cleared it, fault wouldnt come back but on GSP but special progs/sys fault kept appearing immediately on startup.
Used car, came out of limp as got warm. Then used again after a couple of hours and it was a nightmare journey home at like 15mph. Since them limp has stayed. EGR fault sometimes comes back on GAP, have had a MAF fault too on occasion. Have cleaned maf, and MAP sensor that was vile. It had a tuning box fitted that I reverted just to check, no change.
I know a stuck EGR will confuse the hell out of the MAF and could cause limp, its just really odd the special programs fault.
Battery tests fine, have done a recondition charge, hard reset of the car a couple of times, to no avail.
Obv the EGR's are a pain to do, I could have a faulty one thats failed, but it would be a  stripping down to find that's not the issue. Could something else spurious be causing my issue, bearing in mind the dash faults showing? The EGR fault coming up isnt constant, quite the reverse. Sometimes I get an EML, sometimes not. For reference it idles sweetly, revs ok not under load, no noises/smoke/chugging. Air suspension works fine as does the gearbox in manual or auto, and the hi-lo works properly too. Can't be duff fuel as it happened pre-filling. Pretty sure its not the lift pump as have good pump pressure at the schrader valve (I had to end up decanting a lot of the diesel to use in other vehicles while the D3 is poorly so pulled the pump relay and jumpered over. Needs must.....
Thanks gents
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 30th Sep 2021 11:00 pm |
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jonnyboy54321
Member Since: 14 Jul 2012
Location: surrey
Posts: 114
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anyone?
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| 4th Oct 2021 10:26 am |
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Dillon
Member Since: 05 Jan 2018
Location: Brighton
Posts: 103
 
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Could it be a sticky turbo actuator?? Give a spray up/Grease. It's certainly not going to do it any harm.
Good luck
Dillon
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| 4th Oct 2021 1:36 pm |
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Flapper
Member Since: 04 Feb 2015
Location: Gloucester
Posts: 341
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Hi
i agree with Dillon but also check the hoses as i had the same thing checked my actuator which was stuck then checked the hose and found a split about 3 inches long on the long hose from the intercooler to the inlet.
The split was just down from the bend at the top of the hose you couldn't see it from above but using you finger you can feel the whole.
Changed the hose (£12.50 ebay special) took about 40 mins goes like a rocket now and no bongs or lights. 
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| 4th Oct 2021 1:46 pm |
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jonnyboy54321
Member Since: 14 Jul 2012
Location: surrey
Posts: 114
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So i did some more investigation today. Couldn't find the semi-famous red spliced wire despite having the cable ducting out on both sides. My GAP IID showed both circuits of brake light switch acting correctly. Looked at all the multiplugs and ECU behind the battery, all appeared okay.
In desperation I unplugged the EGR's as there had been some spurious, sporadic fault codes. Eureka. All faults gone, special programs returned, ran sweet and would rev to 4K easily on the drive. So i boxed her up as best i could (wiring loom hanging out everywhere!) and went for a spin. N limp, pulls as normal, a little black smoke on acceleration.
So to clarify what was happening, I came home, popped in the GAP, nothing showing. Plugged in the nearside egr, she ran as normal and no special programs disabled warning but came up with an EML, GAP indicated EGR 'A' general signal failure P0405-21 (2D). Could hear the egr clickety clacking upon switching the engine off.
Cleared that fault, unplugged the nearside valve, checked with GAP, all was normal.
Plugged in offside EGR, car craps itself (lol), special programs disabled, into limp etc etc. No codes on GAP, no EML. Switched off, no clickety clack from the offside valve. Unplugged it, car is back to normal.
So these are my assumptions:-
Offside valve is faulty, jammed open a bit, and it is reporting this to ECU generating limp mode.
Nearside valve has a correlation error in ecu when it is the only one plugged in (ie offside isn't) hence an EML, its not a faulty nearside valve, just the offside.
Anyone got any thoughts? Thanks
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| 4th Oct 2021 1:53 pm |
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Flack
Member Since: 06 Sep 2006
Location: Preston Lancashire
Posts: 6270
 
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You need to get them blanked off and a software patch to delete the egr valves, then you dont need to worry about them again.
Flack 
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| 4th Oct 2021 1:57 pm |
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jonnyboy54321
Member Since: 14 Jul 2012
Location: surrey
Posts: 114
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how straightforward is that? Costly?
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| 4th Oct 2021 2:09 pm |
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Flack
Member Since: 06 Sep 2006
Location: Preston Lancashire
Posts: 6270
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You can blank them yourself and just get the patch done, not sure of your area, but post on here for anybody in that area that do the software. Not sure if Bodsy gets down your way, send him a pm and see.
Flack
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| 4th Oct 2021 2:15 pm |
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jonnyboy54321
Member Since: 14 Jul 2012
Location: surrey
Posts: 114
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To close this thread - it was a faulty ebay special offside EGR valve. Unplugging it caused the special programs/limp mode issue to go away. Replaced and all was fine.
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| 5th Jan 2022 10:48 am |
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