Hi All,

I have just started to experience the restricted performance alert whilst driving normally under light to medium engine load. no fault codes are present that would indicate the cause of the issue.

Having read through what feels like several hundred posts with similar symptoms and multiple causes I'm hoping to gather a list of things to check for when I get chance to have a look under the bonnet.

in no particular order this is what I believe the causes could be. (due to no fault codes being identified)

i) Split air hose (is there a common fail point?)
ii) Split Crossover pipe (is this accessed from underneath?)
iii) Split intake manifold (is there a common point where they fail?)


Thanks in advance.

Can I ask what fault scan tool you're using?

I have a GAP IID

PC76 wrote:

iii) Split intake manifold (is there a common point where they fail?)

The twice I have had this pop up repeatedly it has turned out to be inlet manifolds. Maybe 3 or 4 other times dpf full but fixable with a long drive on 3 occasions and on the fourth a forced regen cycle by my local specialist.

Just taken the engine cover off and it looks like I have a small oil leak on the top left air inlet (near side) around the middle cylinder (injector covered in oil).

Now I’m hoping that’s not the cause but know my luck probably will be.... does anyone know what live values I can monitor using the IID to prove what is causing this issue.

Thx

[edit] So I noticed that the small pipe that runs between the two intake manifolds was not seated correctly and pushed it into place, so will check again after some running around this afternoon to see if it has leaked anymore oil...

I also went on a 6 mile test drive and could not get it to go into limp mode no matter how I drove it. I also monitored the pressures in the intake manifolds, along with the boost pressures and mass flow data using my IID. whilst I'm no expert everything seemed equal or as per the expected value according to the the IID tool. so I'm hoping that I don't have an issue with the ink manifolds.... whilst I'm not holding my breath that such a small issue could cause the performance restriction it would act like a leak so fingers crossed..

in order to inspect the air pipes is this done from underneath with the covers removed or do I need endoscope to check from above?

Mine did the same on My12, no codes. It took 4 trips to LR to fix it under warranty. It was the rear crossover pipe, along with a fuel hose that was replaced. 2018 Telsa MS
2012 Range Rover Sport HSE+
1990 Porsche 944
1985 LR 90 Soft top V8

PC76 wrote:

Hi All,

I have just started to experience the restricted performance alert whilst driving normally under light to medium engine load. no fault codes are present that would indicate the cause of the issue.

Having read through what feels like several hundred posts with similar symptoms and multiple causes I'm hoping to gather a list of things to check for when I get chance to have a look under the bonnet.

in no particular order this is what I believe the causes could be. (due to no fault codes being identified)

i) Split air hose (is there a common fail point?)
ii) Split Crossover pipe (is this accessed from underneath?)
iii) Split intake manifold (is there a common point where they fail?)


Check TSB LTB00445v3/2012 for possible causes


Thanks in advance.

Managed to get round to diagnosing the issue this morning, as feared it’s a leaking LH inlet manifold. I also have leaks on the plastic inlet as can be seen on the following photos.

So I have a week off at the end of the month and plan to sort it then along with a few other bits of I have the time and money.

Are there any specific tools required?