Hi everyone from sunny Newmarket U.K. Well it's snowing actually!

Hope that somebody out there can help me with my current problem as it is very frustrating not being able to enjoy the full performance of this car.

The problem started about a month ago after I hadn't used the car for a while. I took it for a short spin and when I returned and restarted the car the amber light and Restricted Performance warning came up on the dash.

I checked the battery voltage and found it was under 11v with the ignition on. As the battery was old I thought it best to replace it with a 100 AH 950 amp CS new battery as I understand low voltage can cause problems with the computer and sensors. However this made no difference to the RP warning.

I put the car on an Autologic code reader and got the following fault codes:- P0202, P0203, P0205, P0208, P0327, and P1647. The first 4 codes are fuel injector circuit malfunction on cyls 2,3,5,and 8. The next 2 are KS sense circuit out of range ( low voltage) Bank A and heated oxygen sensor bank 2 circuit malfunction.

The codes were all cleared all the codes down and the car ran fine for about 2 miles before the RP warning came on again and the same fault codes reappeared. The engine itself runs really smoothly with no sign of misfire until you put your foot down and the RP kicks in.

I can't believe that 4 injectors on different banks would all go faulty at the same time and wonder if it could be a connector or wiring fault? Does anyone out there know where the injector wiring terminates or had a similar problem and knows of a cure?

Thanks for taking the time to read this thread and I hope that someone might have an answer to this problem.

 

First check your charging system, sounds like alternator problem.

 

Hi Anders, What makes you think it might be alternator? I don't know much about the scope of the code readers but I would have thought that it would have shown if there were any problems with the charging circuit. I know that the electronics are quite sensitive to voltage variations, so I will put a meter across the battery whilst the engine is running. The voltage gauge on the dash usually sits around 13v, but I know these are not always that accurate.

 

IT is possible that low battery voltage from a dysfunctional alternator can throw spurious codes but these are not usually among them.
It does sound like a wiring harness problem.
Start by downloading JTIS from the HOW-TOs - it contains everything you will need to address the problem logically.

 

Hi from cold Bury St Edmunds. I don't have the answer to your problem, but we do have an independent Jaguar specialist locally who may be able to assist. My XK8 is currently with him having a new rear subframe fitted (failed MOT due to corrosion). I can provide you with details if you require. Alternatively, a short trip to Norfolk to see Tony (XK Racer) may be worthwhile.

 

Thanks for your post. I often visit Bury and did't know there was another XK8 owner so nearby. Sorry to hear of your rear subframe corrosion, sounds like quite an expensive repair. I have been searching for connector blocks on the injector circuit but have found nothing so it might be useful to contact your jag specialist if you can give me the details.Hope your car is back on the road soon. Regards

 

Hi Rollo

I tried to pm you, but you may not be enabled yet. The specialist I use is Tim Revett who is based near the Sugar Beet Factory. His details can be found here: Tim Revett Prestige Vehicle Servicing - Car Servicing - Bury St Edmunds, IP32 7HX

There is another XK8 in Bury, but unfortunately it has a big wing attached at the rear!

Regards
Chris

 

Trying to get to the ECU to check the connector and see if I can check the wiring for continuity. What could be simpler you'd think?
Just take the lid off the ECU container but no Jaguar have used clutch type tamper proof screws to hold the lid down. Have got two of these out but will have to persevere with the other two.
Who knows one day I may be able to drive the car flat out again but for now I'd be happy to just get the lid off to access the ECU. Do the ECU's go wrong often and can they be repaired or do you just replace them?

 

I had the same type of problems when I put in a new battery. Found out the new battery was half charged, so I put it on the charger overnight and problem was solved.

 

Thanks randyb. It is a new battery and I have never charged it, and the car has only been taken on short trips so I doubt if the alternator has put much charge in.
I will give it a charge tomorrow it must be worth a try, the old battery was definitely down on voltage which seems to be what triggered the Restricted performance in the first place.

 

Have fully charged the battery but still on restricted performance. Got the cover off the ECU and cleaned all the ECU connectors but still no difference.

Has anyone else got any idea what else I can try?

Is it likely to be the ECU itself? it is an LNF141 OBC.

Any suggestions gratefully received.

 

Do a hard reset
https://www.jaguarforums.com/forum/x...connect-74146/
If the RP comes back can you read STFTs and LTFTs?

 

Thanks Steveinfrance, I will try a hard reset. Unfortunately I don't have equipment to monitor fuel trims. The fault codes were cleared with a Autologic reader. This cleared the restrictive performance for about 2 miles but then the faults P0202, 0203 etc etc all reappeared and RP returned. The engine ticks over very smoothly and runs fine until the RP kicks in!

 

By the way Steveinfrance I was overtaken by a Terrot 125 last week but I can still out run a Liebherr just!

 

The Liebherr always wins - except against an MBT (Main Battle Tank).

 

Tried the hard reset, but no change, Restricted Performance comes up as soon as you turn on ignition.

I have the ECU out of the car and in the front room with me and I am now attempting a "mind meld" with the unit itself! It works for Spock so I thought it might be worth a try. Failing that I am going to contact the new Pope and ask for divine intervention.

I would like to try and sort this out myself but as you can see I am running out of things to try. My next step perhaps is to take the car to a Jag specialist and see what they make of it all!

 

I keep on about this but if you've got an Android phone buy a Bluetooth OBD dongle off EBay
Android ELM327 V1.5 Bluetooth Super Mini OBD2 OBDII Auto Car Diagnostic Scanner | eBay
and run an app called Torque on the phone.
You will get lots of useful live data including STFTs and LTFTs
That will help with your diagnosis.
Don't get into the 'throwing parts at the problem' (by all means throw them at the wall, sometimes helps) until we've got into things a bit further.

 

Hi Steve, thanks for your input once again. The Bluetooth reader seems a real bargain. I am not very good with modern technology, so am not sure if it will work with my phone? It's a Samsung Galaxy Ace with Bluetooth and I also have an iPad with Bluetooth but am not sure about the Android bit.
I also notice that it doesn't list Jaguar on the comparability list, but obviously it sounds as though you have tried this device and it works.
At the price it seems well worth sending for one, and hopefully you will be able to advise me how to use it to help diagnose my current problem as I not really conversant with the application of short and long term fuel trims!
Many "tanks"

 

That's the one I bought and it works fine with a Galaxy.
Worth the £3 for the professional version of Torque once you've got it working with the free app.
You plug the dongle into the car, turn on the ignition and the dongle lights up like a christmas tree.
You then pair it on your Samsung.
The only trick is, once paired, you have to get into the torque menu and select 'generic crappy bluetooth' (or similar) as the paired device and then connect.
PM me if you get stuck - it will stimulate me to do a 'HOW-TO' on Torque.
It's an amazing app - all sorts of useful live data including fuel pressure, 0-60 times etc etc.

 

Steve, Does my car have to be OBD 2 compliant to use this? Your vehicle is 2004 but mine is a 2000 model and I am not sure if it OBD 2?