My car has gone into RP mode, when viewing the faults it picked up on a permanent P040d sensor a fault and an intermittent P244B-00 and P2452-95 DPF differential issues.

The car has never thrown a DPF issue on the dash and the soot level is currently measured at 7g.

I’ve taken the car to the garage and the said the sensor is seized and they will need to drop the engine to access in case it shears off, they also said they can’t do until new year as fully booked.

I know this sensor a issue is present on many cars without issue so I’ve asked them to do a high pressure smoke test to see if there are any leaks, when the JLR tech came (instead of AA) he performed a test using SDD to measure airflow he said it failed on idle but passed on 2k revs and 3.5k. He also cleaned the MAP sensor as it was clogged.

I really don’t know what else to do, is there anything else I should look at and would P040D cause RP without the DPF being filled there doesn’t appear to be any other notable codes

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You won't clear a red with P040D in place.
Take it to a specialist and avoid main dealers.
Engine does not need to come out but it's not an easy job. I had Rovertune change mine out 3 years ago. Took them 2 hours.
There is a DIY guide on here in the Wiki if you fancy doing it.
James Henshall at Henshall Engineering fixed a family friends DPF issue. I'd get it to him and leave it with him.... Gone to a good home: 2011 4.4 TDV8 Vogue SE Buckingham Blue with Ivory and clear glass = "Rory"
New Defender D300 90
1974 Series 3 Lightweight = "Millie"
My preferred specialist: www.glenrands.co.uk
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I have had that fault ever since I’ve owned my 11 4.4.
Had dpf alerts a few times but nothing extraordinary.

The weird thing is that although it’s a red fault it’s not a red dpf fault which I know would/could be a hindrance to a forced regen. I have never seen an amber DPF specific fault or the red “contact dealer” fault.

As far as things go the DPF seems to be in good shape with very pow soot levels amd as JNC mentioned it’s common place with little concern which makes me think before laying out loads of money to replace the sensor I should be looking elsewhere

I agree
I have had a permanent PO 40 D etc. fault code for years with no noticeable effect, plus I have performed several DPF forced regens using my iid.

I suggest going back to basics.

Have the 4 short plenum hoses been replaced, or have you still got the original soft rubber type ?

Mike. G reg 2.5VM Vogue Portofino red 1991- 1999
V reg 2.5td P38 Rioja red 1999- 2006
53 reg td6 Vogue Oslo blue 2006- 2015
11 reg 4.4 TdV8 Vogue SE. Baltic blue 2015- date.
https://www.fullfatrr.com/forum/topic56162...tty+affair

Hi Mike,

It’s all original by the looks of it, additionally it’s not long had the oil cooler done ( literally before I got it) so all of those pipes and the throttle will have been disturbed.

Unfortunately I don’t know the name of the test the tech performed but he mentioned it failed on idle and not on power which sort of links in to when it goes RP as that been when pulling up to lights or into get fuel. When it first occurred the AA cleared the faults and we drove nearly 300 miles home without an issue . It failed quite quickly the following day and hasn’t been driven since but the soot level measured was very low.

Another side effect is that when it’s in RP there’s obviously a lot of back pressure with a hissing sound from the passenger side air box and an induction style cha cha cha noise when switching off, this isn’t permanent though and it’s free flowing when not in RP

If you put up a photo of the plenum , just with the plastic engine cover removed, I will confirm hoses.
If they are original, one is odds on to have a small slit in it.
Look for any signs of black oily soot, wiping around with a piece of white kitchen paper is usually an easy way to spot a split, and that would definitely cause an R.P. with no fault codes.
They often fail where the jubilee clips bite into the rubber.
Mike. G reg 2.5VM Vogue Portofino red 1991- 1999
V reg 2.5td P38 Rioja red 1999- 2006
53 reg td6 Vogue Oslo blue 2006- 2015
11 reg 4.4 TdV8 Vogue SE. Baltic blue 2015- date.
https://www.fullfatrr.com/forum/topic56162...tty+affair

I have a similar issue.

I heard some clattering noise coming from the front engine bay which continued when the engine was off. The next time i took the car for a drive there was no noise but it went into RP within a couple of miles.
I took it to a indie who done a diagnostic.

1. Signs of boost leak from around throttle housing also part of the restricted performance fault is due to throttle body faulty. Recommend replacement with new seals.

2. Second part to restricted performance fault is due to a faulty exhaust gas temp sensor located in n/s exhaust manifold requires replacement

I brought the car home to get some body work done while waiting for the throttle body to come in (December sometime, Hopefully). In the meantime I have ordered myself an IID tool to see for myself.

Dazzab1972 Are they sure the sensor is causing the issue or is it that it has failed like most others and showing a fault code?

If it can be changed then yes I’d change it but if you have situation like mine where they can’t get it off it would be interesting to see if RP kicks in after the throttle body has been done.

When I first broke down there was a clatter from the engine but it was too the right of the TB and i think it was a loose clip or something… worth me checking again though 👍🏻

So I’ve been reading up on the fault codes

P244B-68 is advisory only and if shown on its own we we can ignore
P2452-95 relates directly to a dpf sensor fault and the DTC mentions:
The component has been incorrectly installed or pipes crossed, circuits crossed or polarity errors
Sensor hoses not connected properly
Hoses blocked, crushed or split 🤨

Potentially this could point to the sensor or pressure pipes to be the root cause

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The high pressure smoke test came back with no issues so I have been focussing on P2452-95 as that seems the logical culprit.

I started to check the rubber hoses on the pressure sensor and noticed that one of the hoses was missing a spring clip on the end right above the exhaust pipe. Both pipes were removed and checked for blockages and leaks and there were no issues, however, I’m not sure how much pressure there is on these hoses but there’s a high chance that the un clipped hose end would leak especially when warm.

I’ve stuck a new clip on it and so far there’s been no RP, my IID tool comes on Monday so I’ll see if the code still gets registered then.

It may not be the root cause but I feel I’m closer to the problem 🤞🏻

Best decision to get an IID  Gone to a good home: 2011 4.4 TDV8 Vogue SE Buckingham Blue with Ivory and clear glass = "Rory"
New Defender D300 90
1974 Series 3 Lightweight = "Millie"
My preferred specialist: www.glenrands.co.uk
--------------------------------------------------

I believe the P040D code simply means the temp probe has a fault! some may fail in a near normal state and cause the engine to run normally, some may fail in a cold state causing the engine to over fuel (trying to gain temp) this will then fill the DPF with unburnt fuel, and voila DPF issues...
I have seen loads with this fault code, some stink from the exhaust, and some don't. Hence my theory...

1. As others have said you can leave the sensor, change it if you want - but it's not causing your RP

2. Importantly, RP can happen without any error codes.

3. 9 times out of 10 RP is caused by a boost leak on the 4.4

Quote:

I’m not sure how much pressure there is on these hoses

The saga continues:

Having continued to get p2455-00 and p2456-00 which directly relate the the differential pressure sensor I replaced the sensor. These codes have not returned 🎉

However I continue to get p244b-68 differential pressure to high and the occasional RP mode. (Although never had a dpf warning) monitoring soot levels I can see it is regenerating but filling up really fast.

As recommended I’ve decided to look at the short hoses and running my hand under the offside side front it got covered In oil and soot I’ve loosened the clamps and spun the hose over and it “seems” obvious it’s been blowing as there’s still lots of oil and soot surfacing from under the clip even though I wiped a load off when checking. I’ve stripped it down to the point where I need to remove the 4 plenum bolts but I’ve mislaid my star bits so I’ve rush shipped from Amazon.

Could this be the final hurdle???

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