Hi all - new chap here (yes, I've said hello in the new members forum).

I have a 2000 XJR with a few problems that need sorting. The first one I want to address is the P1647 error code it's currently showing. There's no check engine light on and the car drives ok when cold, but as soon as it starts warming up it becomes a bit stuttery and lacking power below 2500 rpm. The error code indicates a likely fault with the upstream O2 sensor on bank 2 so I believe. I've got a new Denso sensor, a lambda sensor wrench and a willingness to get stuck in this Saturday morning (provided the weather forecast for sunshine are correct).

From what I've been able to find here, changing this sensor is a bit of a pig and requires relocation (removal?) of the expansion tank to get at it. As I'm sure everyone's found out for themselves, knowing what to do is a long, long way from knowing how to do it...

I have a copy of the workshop manual, but the instructions seem to imply that the rest of the car will simply cease to exist and not be inconveniently in the way for the duration of the fix, so I'd very much appreciate any pointers before I break out the spanners. So, if anyone's done this before and can tell me what to do (and what not to do) or can point me to somewhere with instructions that would be great!

 

I'm an idiot

Just found this: https://www.jaguarforums.com/forum/x...o2s-r-i-60408/

 

But you learn amazingly fast

You might want to start dosing it and any other fasteners involved in the job regularly with penetrating fluid so that it is well soaked by Saturday.

 

I had this exact fault on my 2001 XJR and the sensor was a pig to change, as there was no space to work.

The expansion tank had to be removed to make space to work-basically, if you can't gain access then you simply have to remove whatever is in the way

Be careful not to snap those small rigid plastic coolant pipes that plug in to the expansion tank-they break easily. The biggest problem is making space to get the heat shield out-it's quite rigid & it won't bend to help removal.

It's not a technically difficult job-just very fiddly & you'll probably have to carefully move the heater coolant pipes out of the way a bit, as well as undo the screws that hold the heater motor in place-so it can be moved slightly to make more space.

If you've never done the job before, then allow a full morning or afternoon for it-you'll progress slowly as you're on the learning curve. Expect your knuckles to get a bit grazed as well

Finally, don't rush the job-take it slow & stay calm, or you'll break something. The heat shield bolts are at an awkward angle & you may need a 1/4 inch drive set with extension bar & universal joint to remove them.

The heater hose clamps are those quick-release spring types, so if you haven't got the correct 'unspringing' tool then you can get away with carefully using pliers or small mole grips to squeeze the tangs together, depending on the angle they're sitting at...

The smaller plastic rigid coolant pipes need a special tool to remove the quick-release connector, but you can do it with long-nosed pliers if you're careful. However, they are brittle & break easily so don't force anything.

Finally, do the job on a cold engine or you'll burn yourself-you need to drain off a couple of litres of coolant which I did by using a length of windscreen washer tubing inserted into the expansion tank, to syphon off enough coolant. You'll also be fiddling around by the exhaust manifold, so you don't want the engine to be hot!

When you refill the cooling system, it may take a day or 2 for all the airlocks to vent upwards & the coolant level may drop enough to cause a warning light on the facia to illuminate. Just top up the system again & make sure there are no obvious coolant leaks.

 

Thank you! That is exactly what I was hoping for

Well, today's the day - the sun is shining, I have the whole day to work on the car, so I can take it slowly and carefully and still have time to go buy any tools I find I'm missing as I do the job.

I have to admit some trepidation: I've done a fair bit of minor work on my cars over the years but doing anything with fluids always gives me the heebie-jeebies!

Wish me luck! I'll report back this evening to say how it went.

 

I did this a few years ago -- as other have said .. just take your time.

I used my trusty turkey baster to drain the tank and then removed the hoses. I normally use "press and seal" stolen from the better half's kitchen to cover all the open hoses and prevent leaks ... yes it works. Move those you can out of the way and hold with tape.

Then look down and move the heat shield -- you will not be able to get it out - just move it out of the way ... this takes more time then anything else!

I had to spray the old sensor with penetrating oil and wait an hour to get the sensor out. I found that the sensor tool with a built in pivoting handle that I picked up from Amazon when I ordered the sensor worked best. It took a few attempts and a few more sprays to get it out.

Make sure not to get any "anti seize" on the new sensor when you reinstall -- and make sure the wires are routed the same way as the OE.

Clean out the tank before refilling -- I just put the old coolant back in and added a little water.

The other side is very easy.

 

I've got as far as removing the expansion tank, disconnected some hoses, removed the heat shield bolts and moved it out of the way. Now I'm stuck. Or rather the sensor is

The problem is the lack of space. I've got two different removal tools - one is a socket with a slot cut out and a hinged handle, like this:



The other is a standard slotted socket for a 3/8" driver, like this:



I can get the first tool on the sensor but there's not enough room for the handle to move and turn the sensor. With the other socket, it's too long and there's no room to attach a ratchet or any combination of knuckle joints and extender bars to make it turn.

Maybe I've not removed enough hoses, but with some of them I can't see any way to get them out short of dismantling most of the engine bay.

Anyone know what I'm doing wrong?

 

That is basically what I had -- spray the sensor and wait -- use the one with the handle to get it free -- and the use the other to unscrew it by hand.

I could only move it about 1/4 turn -- but that was enough.

spray ..spray

 

I must not have enough hoses out of the way. I managed a few degrees at best then ran out of room, but there's not enough space to move the wrench back enough to fit back over the sensor's nut.

Grrrrrrr, so frustrating to get this far then hit a brick wall

 

Yes - I understand

It will come free -- take your time you don't want to damage anything.

.... you must move the shield many times .. a pain.

It took me as long to get the shield back into position as it did to finish up the tank.

 

The issue is not so much the sensor being too tight as the lack of space to turn the wrench. I can get it on but there's nowhere for it to go regardless of how much pressure is needed to loosen the sensor.





It's the hoses with the metal connectors going into the rigid pipes that are the problem. I don't know how to remove them or even whether they can or should be removed (no idea what they're carrying!)

I've given the sensor a good soaking with penetrating oil and will leave it a while longer and see.

Thanks for the help - just wish I could get the blasted thing out!

Oh, I did manage to get the heat shield out though once I'd rerouted enough hoses and cable-tied them out of the way.

 

Well .... Did not see your location.


Obviously with the steering wheel on the other side from mine -- things are different ... but that looks like you should be able to get a socket with an extension on it -- remember you can mess up the wires on the old one so you just have to get a socket on it to crack it loose. The new one will not require the same force -- like installing a spark plug.

Be careful of pushing any of the attached hoses out of the way that strains any of the connections -- these cars are getting old and you don't need any leaks.

I can't tell what they are from the picture -- PS hose would be less of a risk then playing with any of the AC lines.

This may be a situation when you may need to invest in another socket swivel of you don't have one -- still cheaper then the dealer.

This is when Harbor Freight tools is a great asset in the USA - they sell a lot of one time tools

 

Old sensor is out new one is in. Heat shield is back in place, just need to reconnect the hoses and re-fit the expansion tank.

I was told it was a pig of a job - this has to go down as the understatement of the year!

Nearly there - time for a beer break!

 

Keep the faith

 

Well done-that's the worst part of the job over with

It is very cramped down there with not much space to work-it's probably so boxed in that the sensor runs hotter than the one on the other side of the engine, so it fails first. Most of the time it's the difficult-to-access sensor that fails, judging from my own experience & from other threads on here.

The other sensor can be done in less than 15 minutes-it's a doddle.

Nice day for a beer after working on the car-tomorrow's where it all goes soggy & typically British again, according to the weather forecast. Just as well you've done the worst part of the job today

 

Oh, and if you thought that was a pig of a job-wait until you have to replace the front lower balljoints & break the taper. You'll need psychiatric treatment after doing that job

 

All done!

Just taken the car for a 5 mile blast around the local back roads - it did have a little stutter about half way but apart from that it's back up to full power. I cleared the error code before I left and it's not reappeared (so far). I count this a provisional success! I'll be more convinced once I've driven it some more without any further problems.

Many thanks to everyone who posted with advice and encouragement - very much appreciated

Oh, and as far as ball joints go - I'll leave that to my mechanic...

 

So in the end, what worked for removing the sensor?

 

It was a combination of things: lots of penetrating oil, yet more rerouting of hoses including very careful bending of the rigid AC pipes and finally removing the heat shield bracket. I was then able to get the wrench on and turn it a tiny bit, take it off and move it to the other side of the rigid pipes and turn it a tiny bit more. Then repeat ad nauseam until it was lose enough to be removed by hand (in this case by a friend considerably stronger than me!)

 

i was lucky enough to have a rack. so i did mine from the bottom. cut the wiring 'use a ox tool i found and break it loose. then screw new one in. this is a diff tool than you have . i'll post a pic in my garage as i can't put it anywhere else.