Clubber
Member Since: 11 Aug 2008
Location: Teesside
Posts: 372
  
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| Restricted performance MAF? |
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Our Easter few days away got ruined yesterday. Towing the tin tent on the way to Chester on the M62 we got the dreaded restricted performance message on the dash. Managed to get it to Hartshead Moor services and Mayday (Green flag) said the codes pointed to the Mass Air Flow sensor. We ended up on the flat bed taxi home and now I’m waiting for it to be picked up and dropped off at the dealer.
I’m hoping the repair bill won’t be too bad but I haven’t heard of many cheap repair bills so perhaps I should prepare for the worst.
It’s the best car I’ve ever owned so I don’t want to lose confidence in it. 50k miles and it’s only let me down twice so I’m trying to look on the bright side and keep things in perspective. Just need someone to say it’ll be ok and I should keep the faith! 😔 Bri
D4 HSE Luxury
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 3rd Apr 2018 2:50 pm |
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NJSS
Member Since: 06 May 2009
Location: Catherington, Hampshire.
Posts: 10808
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It might be worth cleaning the MAF sensor before incurring expense. Here's how, courtesy of DSL  :-
https://www.disco3.co.uk/forum/topic63478-45.html
NJSS Am I Gammon or Woke ? - I neither know nor care.
2016 Discovery 4 Landmark
2011 Mercedes Benz SL350 (R230)
1973 MG B GT V8 - 3.9L John Eales engine, 5 speed R380 gearbox, since 1975.
1959 MGA roadster - 1.9L Peter Burgess Engine - 5 speed gearbox
Past LRs - Multiple FFRs, Discos & a Series I - some petrol, some diesel,
none Electric or H2 fuel cell - yet.
There are 10 types of people in this world: Those who understand binary, and those who don’t.
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| 3rd Apr 2018 2:59 pm |
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Clubber
Member Since: 11 Aug 2008
Location: Teesside
Posts: 372
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Thanks NJSS
The thread confused me because it talks about MAP sensors but I'm sure the guy yesterday said MAF. I could be wrong though.
Just been out and cleaned it though. I didn't clean inside the hole but it was a bit oily. Fired her back up and still got the same message. I can't reset the fault codes though. Would I need to do that before the car thought it was fixed?
Thanks for the suggestion!  Bri
D4 HSE Luxury
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| 3rd Apr 2018 3:29 pm |
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adam
Member Since: 20 Sep 2005
Location: Home and Happy
Posts: 6917
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Don't stick anything down the little hole in the sensor - expensive mistake (from personal experience)
edit - beat me to it
Could be a multitude of sins - good luck in getting it sorted
Last edited by adam on 3rd Apr 2018 3:35 pm. Edited 1 time in total
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| 3rd Apr 2018 3:31 pm |
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Sheepy
Member Since: 20 Feb 2013
Location: Bedfordshire
Posts: 630
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Check for a split in the hose from the MAF.
Do you get restricted performance message or just the engine-check light on?
And does the performance actually get restricted - ie does the car go into limp mode as soon as you drive, or after you hit about 2k rpm / 55mph?
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| 3rd Apr 2018 3:34 pm |
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DiscoJeffster
Member Since: 27 Feb 2016
Location: Perth
Posts: 204
 
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Can you get us the exact fault codes to help diagnose? It’s probably an air leak and you got an algorithmic error (air measured at the MAF doesn’t correspond to the MAP sensor reading) - e.g. not enough boost for the air taken in through the MAF hence it must be escaping. I’ve had a few of those with various faults to blame.
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| 3rd Apr 2018 3:45 pm |
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Clubber
Member Since: 11 Aug 2008
Location: Teesside
Posts: 372
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Thanks for the replies gents. It’s gone to the dealers now so I can’t check anything else. They said they’ll get the fault codes read tomorrow and let me know what they think.
The lights that are illuminated are yellow engine management and red triangle with exclamation. The message centre reads restricted performance as soon as the engine starts. Actual performance is definitely restricted. 😔 Bri
D4 HSE Luxury
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| 3rd Apr 2018 5:38 pm |
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adam
Member Since: 20 Sep 2005
Location: Home and Happy
Posts: 6917
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Sounds like mine - traced back to a faulty TSOV and subsequently a leak in the intake piping - good luck
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| 3rd Apr 2018 5:40 pm |
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Clubber
Member Since: 11 Aug 2008
Location: Teesside
Posts: 372
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Sorry for being thick but what is TSOV? And is it expensive? 😭 Bri
D4 HSE Luxury
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| 3rd Apr 2018 6:10 pm |
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adam
Member Since: 20 Sep 2005
Location: Home and Happy
Posts: 6917
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No need to apologise - the little I know on these cars comes from far more learned folk than me on this site - TSOV = Turbo Shut Off Valve, cost about £500 fitted - made a sound like a cat in pain when it failed
Could be something as simple and cheap as a leaky seal in the air intake system, lose or damaged pipe etc. - let’s us know what the problem is when you get it looked at
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| 3rd Apr 2018 8:10 pm |
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Clubber
Member Since: 11 Aug 2008
Location: Teesside
Posts: 372
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The garage has just called. They think it is a faulty MAF sensor. They've ordered one for tomorrow and hopefully that'll sort it out. I've got my fingers crossed! Bri
D4 HSE Luxury
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| 4th Apr 2018 4:16 pm |
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90dv
Member Since: 19 Nov 2006
Location: Cumbria
Posts: 62
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if it comes on at idle or just ignition on it will probably be the MAF sensor (detects amount of air going into engine) "OIL" - 1990 200tdi Defender 90
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| 4th Apr 2018 7:39 pm |
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Clubber
Member Since: 11 Aug 2008
Location: Teesside
Posts: 372
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Exactly that; the error message comes on as soon as the engine is started without touching the accelerator. Once it has completed the startup checks, up it pops. Bri
D4 HSE Luxury
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| 4th Apr 2018 8:34 pm |
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Barn1e
D3 Decade
Member Since: 28 Aug 2006
Location: Mid-sussex
Posts: 2021
 
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Have a read through my thread from many years back. In the end it was the lack of power to the MAF caused by a missing fuse. How the car had run fine for so long I have no idea. Since posting that thread I have heard of two others with same fuse missing.
https://www.disco3.co.uk/forum/fault-codes...ht=Fuse+17 2005, TDV6 S, Auto, 190k miles, owned from new, V8 Brake Upgrade, Nancom Evo, RLD protector, BAS EGR blanking & Remap, separate ATF cooler, changing all the fluids ahead of time.
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| 5th Apr 2018 12:47 pm |
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Clubber
Member Since: 11 Aug 2008
Location: Teesside
Posts: 372
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So, a new MAF sensor has cured the problem. I’m really grateful to Stratstone in Stockton, they diagnosed and resolved it quickly so i’m a happy bunny again!
The thought of needing to get a new car was weighing on my mind. I couldn’t think what I would replace a D4 with. Thankfully I get to enjoy mine a little longer! 👍 Bri
D4 HSE Luxury
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| 6th Apr 2018 12:08 pm |
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