Restricted Performance Light on?

[rod3751]

Hi,
2002 XJ308 3.2 SE,
My Restricted performance light is now permanently iluminated along with the check engine light. But the car seems to runs perfectly well with no misfiring apart from the Rev limiter kicking in at 3000 rpm due to the restrictive performance light. (which i find quite dangerous and frustrating when i need to overtake in a hurry or going up a particularly steep incline).
I duly read all the previous forum topics covering this and as usual found a lot of interesting comments and information.
I have to date replaced the air filter, Spark Plugs, cleaned plug connector to Maf sensor and inspected MAF flexible pipe from air filter to throttle body. I Cleaned the throttle body with carb cleaner. The lights are still on.
I purchased a used Maf sensor from ebay but it also made no difference. The performance light used to come on sometimes on a cold winter morning but went off when the car reached normal temp but not all the time. And sometimes recently the light would go off on a long journey but now stays on permanently.
I purchased an icarsoft OB2 scanner but it shows no codes and says "refer to main jaguar diagnostics unable to diagnose fault" i extinguished the lights but they came back on within seconds.
There is forum reference to vacuum pipes from throttle body to engine that may be faulty/split, but i have not been able to identify these pipes. Does Anyone have a picture of their position?
I am baffled as apart from the rev limiter the car runs perfectly well and cruises quite happily at the legal limit and well beyond(as long as i don't exceed 3000rpm).
Can anyone help with anymore suggestions or do i bite the bullet and get it to the main dealer for scanning.
Thanks for reading.
Rod

[RichardSEL]

Hi, 2002 XJ308 3.2 SE,
<snip>

There is forum reference to vacuum pipes from throttle body to engine that may be faulty/split, but i have not been able to identify these pipes. Does Anyone have a picture of their position?

That may be referring to the "Part" and "Full Load" breather pipes that can split but such splits are not easily seen
See the diagram below, have the engine at idle and spray Easy Start at the pipes. If you hear your engine revs increase that means there is a split somewheres along pipe length sucking in extra unmetered air.

[rod3751]

Thanks Richardsel,I'llcheck this out.
Regards
Rod

[Jeroen]

A few more suggestions:

You might have picked this up on some of the other threads. These cars are very finicky when it comes to getting good voltage. So a good battery is essential. Next you have to make sure all the connectors on the battery are ok. I am not familiar with your car, but on my XJR there are two huge main fuses mounted in the boot. They can corrode and cause a voltage drop.

Next it pays on these cars to clean all the various ground/earth connections and there are loads! Same for all fuses and relays.

Having a good healthy battery and sound/clean electrical connections is essential on these cars. Not difficult, just a bit of a job, because there is so much of it.

Endless apparently electronic problems have been reported on X308 forums around the world that were solved by the above!

Otherwise:

Clean and inspect the connectors on the throttle body. Sometimes there is a loose or bend pin, or just dirt/oxidation. For the older models (yours?) there is even a Technical bulletin about replacing the pins on the connectors as they were known to cause problems.

Same with all connectors on the ECU. Disconnect/inspect/clean. You might want to open up the ECU and check the PCB for loose components, split soldering etc.

I have had some restricted performance problems on my XJR recently: Have a look here:

https://www.team-bhp.com/forum/diy-do-y ... ost4467801

You will see some repairs on other cars, but you will also see some images of the manual showing the various ground point, the ECU etc.

https://www.team-bhp.com/forum/diy-do-y ... er-11.html

My restricted performance problems have all been solved. Mind you, I find it very odd you have both restricted performance and CEL but no noticeable performance issues. Which, from the hip, suggest something like a wonky connector, chaffed wire or so.

If you own one of these cars and don’t mind doing a bit of work yourself, it might be worthwhile to buy your own OBS scanner that can handle Jaguar codes. It will at least give you some more idea what could be wrong (or equally relevant whatever appears to be working properly.

Good luck
Jeroen

[rod3751]

Thanks Jeroen,
I will certainly check out all the things you suggested if i can find all the relevant connectors. I do have an icarsoft scanner but as i said in my original post it doesn't give me any codes but it just says "unable to diagnose fault code refer to jaguar main dealer diagnostic system". Also when i extinguish the lights via the scanner,they come back on imediately.
Thanks for your very informative input.
Regards
Rod

[Andy P]

Hi Rod.
Even if everything is working o k you should still get a code,either P1000 which means you have NOT completed all the on board monitoring tests or P1111 which means ALL on board monitoring tests are completed.
You have a MIL(CEL) so there must be code(s).
Try a different code reader / scantool.
It's likely the one you're using isn't compatible.
I use the Elm 327 / TorquePro approach.
This will only read Powertrain (Pxxxx) codes but is as much as is needed for most faults which will trigger the MIL (CEL).
Without knowing the codes which have triggered your MIL(CEL) and Restricted Performance it is very difficult to diagnose the problem or problems.
Keep us posted with your progress.
Good luck.
Andy

[rod3751]

Hi Andy, Yes i think you are right i don't think i have quite mastered the icarsoft i930 or the jag just yet.(Too old i think,i still like playing with the points in my old volvo penta boat engine )
I have been out on the car just now checking all the previous suggestions with the exception of the battery, until daylight has gone. I then used the icarsoft scanner again, This time using the instruction book and entering all the info for my car.
This time i got 5 codes which is something positive. Though they sound expensive
1)P0327 knock sensor 1 - circuit low input - bank 1. (2) P0332 Knock sensor 2 circuit low input - Bank 2 (3) P1646 Oxygen sensor control unit bank 1 open/shorted.
Plus two code readouts as follows - B0327 Fault code not found in datatabase - B0332 Fault code not found in database. A clue might be in that the numbers are the same as Knock sensor codes? but with a B?
Does this make more sense now to anyone and would it cause my problems? Are these sensors doable diy?
Thanks again
Rod

[Andy P]

Hi Rod,
Well done on getting the codes,now we know what we are up against.
The Knock Sensors are easy to replace,they are on top of the engine,secured by one nut:

XJ A27 Knock Sensors Location

You can check a few things before proceeding with replacing them.Is water sitting in the valley beneath the intake manifold. If so it will short out the knock sensor. If you have water it could be a valley hose is leaking. Also, look for water staining around the sensor.
You can check them for broken or damaged wires. If none of that is present then the sensor has probably failed.
Before putting the new ones in use some WD40 and a paint brush to clean the mating surface on the engine for good contact.
Take care not drop the new Knock Sensors,they are very fragile.
Tighten the nut to finger tight and then torque to 20Nm or 14 lb/ft.
The P1646 code,upper oxygen sensor on the drivers side will be a little bit more difficult but it is the easiest side to do.
It is located at the back of the engine after the exhaust manifold and before the catalytic converter:

XJ8 O2 Sensor

You will probaly need a O2 Socket like the one below to get it out,give it a good soaking with penetrating oil first:

O2 Sensor Socket

images.jpg (4.12KiB)Viewed 8998 times

You can try cleaning all connections and check for broken wires before buying new ones but I would say the Sensors need replacing.
Here's a link to the X308 Workshop Manual if you haven't already got one:
https://drive.google.com/open?id=1xjskf ... lyKer5XnEJ
Feel free to download it .
Know what you mean about the points on the Volvo engine,before the Jaguar I was used to a 1981 Harley,no modules or sensors on that,points,spark plug,kick-start and carburettor(good ole days)
The B codes as far as I know relate to body issues but don't know what they relate to.
Will probably go once the other issues have been resolved.
Hope that's of some use to you and good luck.
You need any other info just ask.
Take care
Andy

[rod3751]

Thanks Andy, First class advice/information, and much appreciated.
I was just going to order the knock sensors and Oxyygen sensor now, but i better check for water leaks first. It looks dry at a quick inspection. I have done quite a bit of work on the cooling system about a year ago, replacing the radiator, thermostat and water pump due to an overheating incident at the time. Maybe the knock sensors were affected then? The lights were not on then. I also replaced the plastic cap on the thermostat housing as it cracked when removed. I wish i had replaced the whole unit now with the metal replacement. I felt lucky at the time that the head gaskets were ok.
Took the car From Gloucester to Slough yesterday and Restrictive light went out after Reading and has even stayed out today on a trip to Cheltenham, MIL light still on. I know This won't last as it has done this before recently. I have noticed MPG is not so good though so i will do the work asap.
I was looking on ebay for the oxygen sensor spanners but only found items from China, bit suspicious of quality regarding these.You can't beat good quality tools considering the awkward position of,and possibly tight oxy sensor replacement.
Will keep you posted regards progress of repair. Might be a few days now until parts come. Also its finding the time In between clearing out my fathers flat before sale completion and carehome visits.
Many thanks again.
Rod

[rod3751]

Just an update in case anyone was interested in my ramblings. I Replaced the knock sensors when they arrived and as Andy said, not too bad a job with the help of a guide wire and some quickly fashioned hooks out of old wire coat hanger. I also purchased the upstream oxygen sensor and socket as advised by Andy but failed miserably to replace the sensor from the top. I just could not get enough purchase on the socket to undo the sensor. I could clearly see the sensor and get the socket on it, but an aircon pipe and various other lpg pipes and injector manifolds got in my way and in the end i gave up, not helped by the miserable cold and damp weather.( My garage is presently occupied with a partly stripped down 61 Wolsley 1500, which was meant to be a retirement project but i've never found the time to finish it, so it has to go to get my garage back. The jag will keep me busy in the future)
I also had a lapse in concentration and accidentally leaned on one of the coolant bleed pipes from the header tank to radiator and snapped it at the radiator connector. SNG Barratt came to the rescue there with next day delivery of a new pipe.£30 + pounds lighter that wasn't neccessary. As my MOT is due early December i have decided to get my local garage to fit the sensor at the same time.
Anyway a test drive after reassembly has seen the restrictive performance light extinguished but the check engine light still illuminated due to the oxygen sensor. A scan with the icarsoft 930 revealed knock sensor codes removed with just the p1646 code remaining. Also the mystery B codes have gone. Anyway, some limited success at least and maybe a few pounds saved from the pension pot for future projects. The scanner proved its worth as well. Thank you for all the advice and information which was first class, just what the club is all about. Till the next incident then??????
Rod

[rod3751]

Just to conclude this post. My x308 is now all up and running perfectly, both on petrol and LPG. No warning lights and performance is noticably better,hopefully MPG will be improved as well.
Local garage changed the Lambda oxygen sensor i provided and carried out the annual MOT. She did fail on two rear tyres and some welding on offside front inner sill and offside rear sill/wheel arch within seatbelt mounting area. I am a bit concerned that there is more hidden rust underneath that i can't see. I love the car and would be devastated to have to scrap her after next years MOT, I know renovation can be so expensive. Now i wish i had got proffessional rustproofing done when i bought her 6 years ago when she looked perfect and i was still working. I'm £478 lighter in the wallet but happy to get at least another year out of her.
Thanks to Andy, Richardsel and Jeroen for their very helpful advice and information.
Regards
Rod