Hello everyone.

First up, i would like to thank the admins for this amazing resource and would hope i am not being a leech by making my second post a help me please post.

Car: Jaguar XJR 2008 supercharged

History: Purchased in January 2014 from a friend. Car had some problems but got it fairly cheap, so bought it.

In jan, the car was overheating every few KMs with complete drainage of coolant. gave to a local mechanic, he supposedly changed the following: supercharger pump, water pump, some hoses. Car became ok after spending a lot of money on it.

Current status: Car always gave me Bank 2 Sensor 1 low voltage and circuit errors on obd (p0051 and p0151). Took it to my trusty mechanic, got the o2 sensor on the left side changed with an aftermarket used one. I replaced the left side sensor with right side one. My car gave restricted performance after each spirited drive taking revs over 3k-4k for about 15 mins. However, running the car with cruise control meant no errors and stable drive without problems

Currently the following errors show:

1. P0131 - Powertrain - o2 sensor circuit low voltage (Bank 1 Sensor 1)
2. P0171 - System too lean (Bank 1)
3. P2601 - Powertrain - Coolant Pump Control Circuit Range/Performance

1 & 2: I think the sensor that i replaced (it was a used sensor that i got from a scrap yard) is faulty which is causing the lean on bank 1 and the circuit low voltage. I will order new from amazon and replace. I hope this will take care of it. still have rough idles and slightly rough running with RPM jumping slightly up and down at same gas press at low speeds.

3. This is something new that has popped up. I've read on the forum and people have mentioned two things - Supercharger pump, intercooler pump. I see one pump behind radiator, which looks like intercooler pump from pictures on ebay. I'm trying to listen with ignition on without starting and cant hear any sound. I assume this pump is faulty from the looks of it. Have checked the fuse 24 of engine fuse box as referred in handbook, it is fine. have plugged it out and in and started the car, in both cases, no change in any sound of water pumping.

I have tracked the coolant temperatures at 90-95 degrees celsius in my obd. But these temperatures have persisted even before i got error 3. Now my car is giving restricted performance even through cruise control. The temperature gauge doesnt go up.

What would be the suggestion, to keep driving like a toyota corolla with slow steady pace, or should i park it till get the above fixed. Would appreciate if the gurus here could poke problems with my above suggestions.

 

The supercharger pump is located on a right side of a radiator behind a bumper.
There's also a aux pump, which is located on a right side of a fan shroud, between a shroud and engine.
The SC pump failure will not affect a coolant temp., it will affect an IAT2 readings.
There's a lot of threads on this forum about this pump, IMO it's better to replace it with Bosch 010 pump, but it will require some work with wiring.

 

Hi qasimak,

I can't tell you anything about 1 and 3, but P0171 is a very common OBDII code that typically indicates an air leak somewhere between the MAFS and intake manifold gaskets that is allowing unmetered air into the combustion chambers, causing a lean AFR that the ECM cannot correct by enrichment.

It is possible that this code is due to the questionable O2 sensor, so I'd replace that first with a correct new one. I would highly recommend that you purchase an 02 sensor of the same brand as the original (not sure what brand our X350s use - I think it's Denso but it could be Bosch or Delphi), and buy one that has the correct harness length and correct electrical connectors already installed. The Internet is full of stories of problems folks have had with the "universal" O2 sensors that require the user to attach the electrical connector.

As far as the other codes go, have you downloaded the X350 Workshop Manual in five or six parts from the X350 'HOW TO' quick links thread of this forum? The Workshop Manual gives brief but sometimes very helpful potential causes for each fault code. Codes that begin with P will be found in the Powertrain section of the manual, and you can search for them using the Adobe Acrobat Reader search function. If the search window is not present at the top of the page, hold the Ctrl or Cmd key and press the F key and the search window will appear. Type in a fault code and press the right arrow to find the next occurrence of that code in the manual. Keep pressing the right arrow till you find a reference to that fault code with an explanation of potential causes.

Cheers,

Don

 

serious problem today. very rough while driving with IAT over 94 c while ambient was 43 c. coolant temps consistently over 90 c with highs of 95 c. RP came on in the last 5 km of a 50 km drive.

I've cleaned the MAF with an electrical cleaner which gave good performance for a day.

still getting P2601. am thinking of changing auxiliary pump as well.

Whenever i open my engine bay, its usually sweltering.

 

Well, the IAT readings are pretty normal, there's nothing to do witm MAF.
Check an IAT2 reading, if the pump had failed it will be way to high.

 

qasimak,

The thread at the link below reminded me of your P0171 code. You might check the same hose fitting (and others) on your car:

https://www.jaguarforums.com/forum/x...solved-117387/

Cheers,

Don

 

Hey guys,

I'm back after spending lots of money and repairing the follows:

-catalytic converter replaced (second hand, last ones gave out)
-all plugs and maf and ignition coils replaced

Now car is throwing the following codes:
- bank 1 and 2 sensor 1 o2 voltage too high and too low (only sensor 1 on both banks)
- system too rich
- car vibrates like anything and revs go very high and doesn't shift up.

The car was checked by dealer and they asked me to fix the catalytic converters out as they believed it was choked. Have replaced them with a car driven 30,000 kms.

Dealer checked for all vacuum leaks and cleared the car, but cat conv was causing back exhaust due to choking.

What could be causing this, any ideas? My mechanic is asking me to replace throttle body, will that fix this?

I want to thank you guys in advance for your time

 

Hey there, thanks for your post, sorry about your troubles.

No worries about the help required post, after all its what we're here for!

Hopefully some of the tech guys / gurus can offer help and further advice towards a fix.

Please keep it live by adding any details as required, fingers crossed for you

 

You can the O2 voltage low and high with good sensors
This can just indicate it out of range not that is faulty

Things that come to mind are a vac leak, pugs, coils and manifolds

As you have the issue on both banks you need to look at the things that effect both banks first all though it is possible but less likly you have a fault on both banks

Simple things to check
Check the inlet pipes downstream of the maf for leaks and make sure the clamps are tight
Do a smoke test on the inlet vac system
Check the full load breather
Check the inlet and exhaust manifolds are not leaking and ate tight
Check the exhaust flanges on the exhaust manifold

Re the 02 you have 4 sensors (2 on each bank)
The upstream one is a wideband lamda type and the downstream is a narrowband
The downstream is used to monitor the cats

If you have torque graph the 4 sensors
You should see the downstream follows the upstream with a slight delay and both banks are roughly equal

Also monitor the AFR and trims
The AFR is always trying to get to 14.7. The upstream sensor is used to adjust the AFR. You can see this in the fuel trims. These should be close to zero if you have good plugs/coils and no leaks. The effect of a leak is more air and less fuel. This is seen by the upstream sensor which pushes up the fuel trim to adjust. Once this get to 25% you get the restricted performance.

Likewise a plugs and coils that bad will not burn all the fuel resulting in more air at the upstream sensor which pushes up the trims as well

Im not sure on the mileage but I'd start with the smoke test, fix any leaks and check the manifolds bolts. Thiese are simple to do and don't cost anything. Next Id replace the full load breather. Its not that expensive compared to the plugs and coils. Even it that does not prove to be the issue you will need them eventually.

Here is an example of how the loose exhaust flange drive up the trims
LTFT Fixed

Also my post on making a smoke tester for a few bucks
https://www.jaguarforums.com/forum/x...-leaks-117917/

Hope that helps
Cheers
34by151

 

Thanks for your reply. However my problem is a rich condition. My understanding of a vac leak is causing a lean condition. Plus my transmission is not happening once the car is showing the o2 errors. Shifts fine at low pedaling but at aggressive driving gets stuck

 

The most likely cause are bad pugs and or coils but these are relatively expensive to replace.

If you had the issue on one bank only I would suggest swapping them between banks so you can work out which ones but you don't have that option

Doing the other simple things first is quick and cheep to do. Call it preventive maintenance. Your gearbox issue may be related as the 2 systems (ECU/TCU) are linked but as I indicated you may have multiple faults.

A single issue can often trigger multiple codes and faults and you need to concentrate on the big issues first. Taking care of the engine issue may solve the trans issue. The trans may also be solved by a reflash and or another repair but really you need to solve the engine issue first

PS there is also a big difference between a running rich and a rich code
A vac leak and or an exhaust leak will cause more air in the charge (lean) but the o2 will sense this and increase the fuel trims making the engine run rich

A Spark issue (dead pug or coil) will also show up as engine misfire codes however one or more partially bad pugs/coils generally will not show misfire codes but produce a rich condition. The O2 will again compensate as best it can and make the engine run lean

A bad full load breather can go either way depending on if it is passing vacume or dumping oil in the inlet. (some oil is normal especally on the S/C versions)

I know you posted you had the coils/pulgs and MAF replaced but you also said it was done by a *******.

Did they give you the bad parts or just charge you for them?
Is it possible they charged for something the was not replaced as this is not that uncommon for a *******

Assuming they did replace the parts was an ecu reset done.
Probably not, try that as the LTFT's may be way off due to the learning in the ECU
IE it was commentating for a fault that no longer exists and has not learnt to go back the other way

You started with a Lean code and a restricted performance most liky caused by a leak or the pugs.
This would have pushed up the fuel trims (LTFT) beyond 25% producing the restricted performance
Lets say it was the plugs and they were replaced, the trims are stills up near 25%.
The restricted performance goes away as it drops below 25% but the LTFT are still high due to the learning. net result the engine is getting too much fuel (rich) due to the trims

You may drive out this condition but the best thing is to do a battery off reset of the ecu and relearn.

Its also hard to diagnose on the lift, you need to monitor the trims and drive it
Get yourself a copy of torque and monitor the 4 fuel trims. Both banks should be under 5% but your goal is a net 0%
Monitoring the trims tells you everything

You may also want to read the fuel trim primer pdf's

Cheers
34by151