P0472 Exhaust Pressure Sensor Circuit

[rsharpe]

Does anyone have experience of a P0472?

I've got the dreaded "Restricted Performance" red light; it happened about a month ago but cleared after stop/start. It has now re-appeared and stored a code (there was no code on the first occasion).

Hopefully covered under my warranty but just wondered what to expect?

[Marineng]

Good morning
I have not experienced this fault directly myself but had the 240ps diesel in my XE. I understand that there are two pressure sensors in the exhaust system which are before and after the particulate filter. Communication between the two is as important as their correct operation.

I hope the warrenty covers the problem.

Kind regards
Paul

Paul Russell
SUV Coordinator
Jaguar Enthusiasts’ Club

[rsharpe]

My Jaguar dealer was unable to fix this, because the code is intermittent. It alludes to an electrical fault in the sensor circuit, and on the day it went in of course behaved itself. They could replace the sensor, but have no way of knowing if that is the correct course of action, until, sometime in the future, it happens again. But then the warranty won't cover another attempt to fix it (e.g. it may be a wiring issue or software, or something else).
The restricted performance mode is quite drastic! It has now happened three times, some thousands of miles and few weeks apart. It looks like I am destined to live with it until such time as it becomes a hard, constant failure. Or maybe it never will.
The fix is to do the old 'switch it off and back on again'. I have been lucky so far as it has always 'failed' at low speed, so I have been able to easily pull over and switch off. I just hope it doesn't happen on the motorway.

[Marineng]

Hi rsharp.
I personally am really surprised at this, as I know just how tricky a sudden move to limp home mode can be - I would have though that is would have been a primary duty of the dealership to get this sorted.

Do you know what they have done besides just looking for a fault code?

Kind regards
Paul

Paul Russell
SUV Coordinator
Jaguar Enthusiasts’ Club

[andypryce]

I agree, surely if it is under warranty they should replace the sensor(s), and if it still happens then at least that has been eliminated as the cause? As you rightly say, limp home mode can quite dramatically reduce performance, not fun at speed on a busy motorway...

[rsharpe]

Thanks Paul/Andy,

They had it under the microscope for a while and trended the sensor but it was behaving perfectly.

I am from a maintenance background so I know these intermittent faults can be tricky to track down with any certainty. They were very open about the options; happy to change the sensor (and happy that the warranty would cover it) but also clear that it was a once only offer. If the fault re-occurred with the new sensor then I was on my own (at my cost). To be fair to the dealership that's down to the warranty provider. I reckon if the sensor is not the cause then it's either a wiring/connector/loom fault (very difficult and expensive to find) or maybe even software.

I also considered financing the sensor myself; if I can get one at reasonable cost. Apparently the Jaguar one was £170 VAT plus of course fitting.

The engine was new in May - but that's a story worthy of its own post! I don't believe in coincidences, so it could be related.

Thanks,

Richard

[andypryce]

Tricky one then. The trouble is you are now just waiting for it to happen again, which tends to ruin the driving pleasure.

[Marineng]

Interesting - you are correct about the diffuculty of diagnosing an 'intermittent' fault, unless it appears while you are watching. However, have a look at the attached file which has come from the Jaguar repair guidance available to dealers. I do agree that finding an intermitted fault is not easy but there is some good information in the guidance.

Good luck
Kind regards
Paul

Paul Russell
SUV Coordinator
Jaguar Enthusiasts’ Club

[rsharpe]

Paul, thanks for that information. The sensor has now been replaced so hopefully it's all over - can't be sure for about another month!

The fault re-occurred a few times in close succession, so whatever failure had been brewing for a couple of months decided to stick around. It became almost permanent so was easier to locate. I chose to get the car recovered to the dealership by my breakdown service as I didn't feel it was great to be driving through rush hour traffic.

This is the latest in quite a long line of failures - I'm so glad I've paid for the warranty but having to use it so often is disappointing in the least. And it's £1000 per year I hadn't planned on spending.

Thanks for your support - I have a feeling I'll be back soon!