I'm talking about inlet manifolds not plenum as per Gary's comment  Gone to a good home: 2011 4.4 TDV8 Vogue SE Buckingham Blue with Ivory and clear glass = "Rory"
2025MY Defender D350 90 in Silicon Silver on coils
1974 Series 3 Lightweight = "Millie"
Many, many other Landies over the years
My preferred specialist: www.glenrands.co.uk
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 2012 TDV8 Vogue (L322)

I have had several instances recently where the "Restricted Performance" warning has come up which then clears when the engine is shut down and then restarted after a bit. There are no faults showing on the IID tool, apart from the P040 EGR Sensor A which they all seem to have. The DPF is not full.
I have already had all 4 short hoses on the plenum replaced some time ago as a preventive measure. On removing the plastic engine cover the only thing which seems unusual is that I can get a bit of movement on the hose junction marked in red. Could there be an air leak here which is causing the problem? It is not secured by a normal jubilee clip, so there does not seem to be a way of tightening it.
Any suggestions would be appreciated.

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That joint is always loose and can't be tightened as the elbow is rigid plastic. If there is a leak from the interior sealing lip you will see oily gunk around the elbow. 2012 TDV8 Vogue (L322)

I replaced the whole thing on mine as part of my preventative maintenance program. Old one was a bit sooty.
Took 5 mins.
You can take that spring clip off, squeeze it and then refit. Some folks have also used PTFE to make a tighter seal inside for the green seal.... Gone to a good home: 2011 4.4 TDV8 Vogue SE Buckingham Blue with Ivory and clear glass = "Rory"
2025MY Defender D350 90 in Silicon Silver on coils
1974 Series 3 Lightweight = "Millie"
Many, many other Landies over the years
My preferred specialist: www.glenrands.co.uk
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scuddriver wrote:

I have had several instances recently where the "Restricted Performance" warning has come up which then clears when the engine is shut down and then restarted after a bit. There are no faults showing on the IID tool, apart from the P040 EGR Sensor A which they all seem to have. The DPF is not full.
I have already had all 4 short hoses on the plenum replaced some time ago as a preventive measure. On removing the plastic engine cover the only thing which seems unusual is that I can get a bit of movement on the hose junction marked in red. Could there be an air leak here which is causing the problem? It is not secured by a normal jubilee clip, so there does not seem to be a way of tightening it.
Any suggestions would be appreciated.

Click image to enlarge

This is well known for failing - a poor design in my opinion.

Inside the plastic pipe is a double lipped rubber seal, which isn't really substantial enough. Over time this collapses in places and leads to intake leaks.

Here's a photo with some sections collapsed highlighted:

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There's 2 options:

1 - buy the replacement part. It's £170 and permanently solves the issue. Takes 5 minutes to fit.

2 - buy some gas specification PTFE tape (about 80p) from Screwfix/Toolstation, wrap it around the throttle body then re-fit the pipe. This is what I have done (for now) and 1,500 miles later, is working fine. I can't say how long it will last obviously but, a good and cheap interim fix / diagnostic before splashing out £170.

 2015 Range Rover Autobiography 4.4 SDV8

That is most helpful - thank you.
Do you have any tips about removing/ refitting the metal clips that hold it in place? 2011 Vogue TDV8 4.4
1992 Mazda Mx5

it just flips out with a screwdriver but hold it as it can spring out and into some unreachable crevice in the engine.....
Be extra, extra careful with the connector in the bottom right of your picture as it can snap even if you look at it the wrong way. 2012 TDV8 Vogue (L322)

Thought I'd post an update.

The new inlet manifold is expected at Land Rover on 6 October so I'm hoping to have the car back by the middle of the month.

Cheers,

Steve.

I keep getting the "restricted performance" warning which occurred again yesterday but with no "limp home" mode. Thid usually clears when the engine is stopped for a while and restarted.
When I got back I left the engine running and plugged in my IID reader. It came up with 3 engine ECU faults.
the one which clearly triggered the warning was the P0105-16 manifold absolute pressure/barometric circuit general electrical failure. On clearing the faults the "restricted performance" warning disappeared. the P040D one of course recurred.
Has anyone experienced this P0105 fault or know how to deal with it?

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I had the map sensor fault once when I removed it for cleaning and didn’t plug in the connector properly so check that. MAP sensors are not expensive so maybe just change it. 2012 TDV8 Vogue (L322)

You should try cleaning the MAPT (manifold absolute pressure and temperature ) sensor.

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Mine was totally blocked with soot and oil paste but still kind of worked so not sure this would throw a code. Cleaning it IME just gives you a crisper throttle response as it can react more quickly the pressure variations. Should be cleaned every 6 months or thereabouts. 2012 TDV8 Vogue (L322)

thanks Guys,
A 5 minute job as you said. My sensor was caked in soot, but brake cleaner did the job.

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That looks clean - this is when it's bad (but still not throwing a code).