How to change a Knock Sensor on a Jaguar AJ27 Engine FAQ
 

How to change a Knock Sensor on a Jaguar AJ27 Engine

One of the common problems of the Jaguar V8 engines is knock sensor failure.
A faulty knock sensor will set the ignition timing in full retard and you'll get only a weak performance.
The failure is accompanied by the amber warning light and a DTC Message "Restricted Performance".
A knock sensor failure has not to be a permanent problem. Intermittent failure is common, but still the sensor has to be changed to get rid of the problem.

To verify if the problem is indeed a knock sensor failure and to check whether it is Bank 1 (right side of the car) or Bank 2 (left side of the car) you'll have to get the OBD codes read out.

The codes are as follows:

P0325 Knock Sensor 1 Circuit Malfunction (Bank 1 or Single Sensor)
P0326 Knock Sensor 1 Circuit Range/Performance (Bank 1 or Single Sensor)
P0327 Knock Sensor 1 Circuit Low Input (Bank 1 or Single Sensor)
P0328 Knock Sensor 1 Circuit High Input (Bank 1 or Single Sensor)
P0329 Knock Sensor 1 Circuit Intermittent (Bank 1 or Single Sensor)

P0330 Knock Sensor 2 Circuit Malfunction (Bank 2)
P0331 Knock Sensor 2 Circuit Range/Performance (Bank 2)
P0332 Knock Sensor 2 Circuit Low Input (Bank 2)
P0333 Knock Sensor 2 Circuit High Input (Bank 2)
P0334 Knock Sensor 2 Circuit Intermittent (Bank 2)

There are two knock sensors located on top of the Engine, approximately in the middle of the 4 cylinders at each bank.
To get access to the sensors the black plastic engine cover with the "Jaguar V8" imprinted on has to be removed.

There are two types of knock sensors.
The "old" ones that are of a "screw-in barrel type" and the newer ones that are just bolted on.

I describe the replacement of the bolt-on type knock sensor on Bank 2 in the following documentation on a 1999 XJ8 AJ27 engine.

Be careful!
Knock sensors are piezo electric devices that are very sensitive! If dropped, over-torqued or struck they will probably be destroyed.
As knock sensors are sensitive to a sudden temperature change they are also easily fractured by steam blasting a hot engine.
So handle the knock sensors with great care and let the engine always cool before fitting a new sensor!



Here's my How-To-Write-up...


That's where we start...

http://www.mediafire.com/view/?kv4r2ha6ts2zvv8


Remove the black plastic engine cover.
(It is just clipped on so just unclip the two black plastic hoses on top of the cover, bent them slightly away, and pull the cover off.)

http://www.mediafire.com/view/?ufl4nawpxag6tel


In here's the left-hand-side knock sensor hidden...

http://www.mediafire.com/view/?weskun8t0xwvi2l


Unplug the electrical connector of the knock sensor located at the side of the black plastic thermostat housing.

http://www.mediafire.com/view/?m7rxde7avb8dx3a

http://www.mediafire.com/view/?ij3j239etvbbteu


Remove the connector from the retainer clip.
(To not break the connector use a small bent tool to push the latch of the connector back and slide the connector downwards and off it's retainer clip.)

Here's my "tool" :icon_lol: and a close-up of the connector:

http://www.mediafire.com/view/?4l5oxfkj74xd2e4

http://www.mediafire.com/view/?ee4k7940oa89atc http://www.mediafire.com/view/?5k8odfwso5l7d7r


"Special tool" in use...

http://www.mediafire.com/view/?8iqq73bpsgb0nry

http://www.mediafire.com/view/?e5b1bj2gg5e356y


Loosen the 13mm screw nut that holds the knock sensor.

http://www.mediafire.com/view/?tf6rca0rt9a4d5e


Fill a 13mm wrench socket with grease to hold the nut in the wrench socket.

http://www.mediafire.com/view/?tf83r9bcvtc7sv3


Remove the screw nut and carefully lift the wrench with the nut "glued" into it up.

http://www.mediafire.com/view/?4x6b1c4w2obwbuy


...

...
Get yourself two pieces of wire and bent one side into a small U-hook.

http://www.wasserski-frankfurt.de/Jaguar/Knock-14.jpg


Use one U-Hook to pull up the knock sensor and with the second wire carefully guide the attached cable and it's connector out.

http://www.wasserski-frankfurt.de/Jaguar/Knock-15.jpg

http://www.wasserski-frankfurt.de/Jaguar/Knock-16.jpg

http://www.wasserski-frankfurt.de/Jaguar/Knock-17.jpg


Here's the defective knock sensor vs a new one.

http://www.wasserski-frankfurt.de/Jaguar/Knock-17a.jpg

(I ordered the new ones with www.autopartswarehouse.com, Item No W0133-1655837, $27.95 free shipping to the US.
They are for a XKR but fit theXJ8 as well. Only difference is that the cable is a few inches longer than the one of the original sensor, but there is enough room to tuck it away nicely.)

Use some WD40 and a paint brush to clean the surface on which the knock sensor was/will be mounted.

http://www.wasserski-frankfurt.de/Jaguar/Knock-18.jpg

http://www.wasserski-frankfurt.de/Jaguar/Knock-19.jpg

http://www.wasserski-frankfurt.de/Jaguar/Knock-20.jpg


Insert the connector and the wire, guide it with the U-Hook-wire towards the front and lower the knock sensor onto the bolt.

http://www.wasserski-frankfurt.de/Jaguar/Knock-21.jpg

To insert the new knock sensor use the shaft of a wooden spoon (or something similar) to hold and guide the knock sensor into position.

http://www.wasserski-frankfurt.de/Jaguar/Knock-22.jpg

http://www.wasserski-frankfurt.de/Jaguar/Knock-23.jpg


Hold the knock sensor in place with a large screwdriver and carefully remove the wooden shaft.

http://www.wasserski-frankfurt.de/Jaguar/Knock-24.jpg


Slide the connector onto the retainer clip and connect it to the harness.

http://www.wasserski-frankfurt.de/Jaguar/Knock-26.jpg


Grab the wrench socket with the 13mm nut still "glued" in and carefully guide the nut onto the bolt.

http://www.wasserski-frankfurt.de/Jaguar/Knock-25.jpg


Tighten the nut to hand-tight. (Torque = 20Nm or 14 lb/ft, thanks to "xjrguy" for the torque data!).

Replace the engine cover and you are done!

It took me about 15 Minutes per side but I have been there before.
(As my first DTC appeared I interchanged the knock sensors just to be sure that the knock sensor was the culprit and not some bad wiring/contact.)


Good Luck!


David

P.S.
To follow that write up is completely on your own risk!
If some damage occurs following that write-up I'm in no way responsible!

Nice write up. Thanks!

Thanks for your time and pics , this will be FAQ

2 things to add
1) many times that little plastic rib on the intake runner keeps you from taking the knock snesor up as it interferres. Break or cut it off with side cutters.
2)i just use a telescoping small magnet for the nut and knock sensor to feed in/out. Anyone that works on a car should have 1 for droppped tools, bolts/nuts and install removeable of many metal parts. Works real well on stuff under the car that always seems to roll under the car furthest fromt your reach.

Sweet DIY man. I need to do this soon and this helps a lot. Thanks!

THANKS for taking the time to do this DIY post! I ordered two knock sensors and if the lenght of the pigtail is the only difference...I saved myself a lot of $$$$$. Thanks a lot!

The AJ85676 is designed for the 4.2 engine ( BTW $27 is the full jaguar list price).
4 liter engine, being XJ or XK, use the LNE1692AA which is way more expensive at $100 list.

I'm not sure if that matter but I would worry a bit about using sensor designed for an other type of engine.

I'll give it a try since it has been done before. If it is not the right set-up it will probably show some DTC's and I'll take them out. Thanks for looking out!

You won't regret that decision. :icon_wink:

Wow...Only a month old....Well, let me be late to the party as usual. I went to do this job today on a clients 1998 Vanden Plas with the 4.0. Sadly, it requires a 15/16 socket to remove the knock sensors. Why "sadly"? Because a 15/16 wont FIT in between the intake runners. I'm pretty sure this will require a removal of the intake? Anyone else know?

I'm pretty sure I used a long skinny metric socket (12 or 13 mm) with a flex extension. The left side went easy but on the right side (passenger side) you might need to brake the plastic edge (runner) that is in your way. It won't hurt anything doing it. Have fun!

P.S. The knock sensors listed by David work just fine on my 2001 VDP and they were a lot cheaper.

No, when I say 15/16 socket, I don't mean metric. I mean SAE. Mine is DIFFERENT from the one pictured in this write up for some odd reason. It's ok though...I just clipped the wires, re-wired the connector plug, and checked connections. Then I went and had the codes cleared, and now it is fine. :icon_wink:

So you probably have the older barrel-type knock sensors.
I have no experience how to remove these...

AJ85676 vs LNE1692AA question
 

Hi Folks,
First, thanks, fantastic writeup. I have an intermittent knock sensor problem since a coolant leak (heater pipes in the 'v').
How confident are people that the cheaper AJ85676 will substitute for the stock LNE1692AA (1999 AJ27 3.2)?
I know it will cure the fault codes, but my worry is that it might be less sensitive to knocking (and allow engine damage over time) or more sensitive and restrict performance.
If you have retrofitted AJ85676, have you noticed any extra pre-ignition?
Are the two parts manufactured by the same company?
My dealer recommended the OEM LNE1962AA and would not be drawn on the suitability of AJ85676.
Thanks, Aidan

Both knock sensors are made by DENSO to Jaguar specifications.
I changed both knock sensors with the "cheaper" ones I mentioned above, use them now since half a Year without any problems.

If you are still concerned - go and buy the original (more expensive) part and if it is just for your peace of mind.

David

RE: AJ85676 vs LNE1692AA question
 

Thanks David,

Your experience is good enough for me. I have ordered one AJ85676 and hope to fit it at the weekend.

Cheers, Aidan

Update:

Fitted cheaper AJ85676 in June. No fault codes or knocking since.

Thanks Again, Aidan

the "spec'd" torque gives the required sensitivity, more/less torque = more/less sensitivity

I've been running with the ones suggested by Dave for almost three months now...so far, NO PROBLEMS!

Excellent!! I need to do bank 2 on my vdp.
This will help!!
thx

Just replaced mine, bought a denso for $60.00. Was 4" longer than the old one. Torqued to 14 foot lbs. Guide was great.

Priced the sensors up to 173.00.

Ant, where did you get your Denso sensors? The W0133-1655837 (used by DavidN) from autopartswarehouse is NLA. Exact ones for XJ8 seem to be $100 and up. The ones for XK8 (longer wire) are somewhat less, but not that much less.

I do wonder how different these sensors are. I found one for a 4.2 L Jag that was really cheap. Also, there is another style which has its own stud to screw into the block, that is also cheaper.

Hi Boomer
I did a little research on the internet this morning, looking for 2006 XJ8 knock sensor.
I found 2 sources here in US and 1 in the UK.

Rock Auto Parts has a Airtex part# 5S5619 that is an alternate/OEM for AJ85676, SU7012 - Price $27.79 plus around $9 shipping.

Attachment 169889


The other one is on Ebay is also Airtex part buy-it-now priced at $40.42 free shipping:

Airtex 5S5619 Knock Sensor | eBay

British Parts co uk has the original Jaguar part AJ85676 priced at 17.82 British Pounds - total cost 28.52 British Pounds.

KNOCK SENSOR

Jim Lombardi

Found it on ebay.

JAGUAR XJ8 S-TYPE SUPER V8 X-TYPE XJR XK8 Knock Sensor | eBay

They list it as OES genuine.

That was the cheapest I could find.

Didn't see those that Jim posted.

Note: The $27.00 one at rock auto is actually $64 or $70 for my car w/out shipping.(and it's the wrong item, not for XJ8 2003)

I paid 60.00 shipped for the denso.

There were lots but every time I indicated XJ8 2003 4.0 the price was high if they even had it.

Hi ant17
The part number that David provided in this DIY writeup was the alternate for Jaguar part# AJ85676. Rock Auto Parts Airtex 5S5619 is also the alternate part number for it.

David it not go by the cross reference you are trying to use.
That is why I used 2006 XJ8 to look it up on Rock Auto Parts catalog.

Jim Lombardi

Jim -
The Rock Auto $27.79 one for the 4.2L is the one I had found the other day. It is cheap enough that "as a service to humanity" I am tempted to buy one and try it out in my XJ8 4.0.

Hi Boomer
Update - the OES knock sensor ant17 bought on Ebay is also for the 4.2 engine - I just look at the compatibility chart in the Ebay Listing.

The Ebay listing for AirTex knock sensor has a compatiable table showing 1997 thru 2002 XK models with 4.0 engines along with all the 4.2 engines.

Airtex 5S5619 Knock Sensor | eBay

The knock sensor that David describes in the DIY and used is also for 4.2 engine. Both knock sensors are made by DENSO to Jaguar specifications.

Forum member luc posted "The AJ85676 is designed for the 4.2 engine ( BTW $27 is the full jaguar list price)."

Jim Lombardi

If I ever need to replace the other one, I may try the $27.00.

Every one I looked at by every single seller did not have my car listed as compatible.

Just the one I found, and the $173.00 one.

I wouldn't bother too much even if the knock sensors are rated for the 4.2 Liter engine.
Mine are still working perfect!

Cheers,

David

DavidN,

I think I may have purchased teh wrong knock sensoer for my 1998 xjr. See teh attached picture. These are not correct, right?

The "correct" knock sensor fits over a stud that is screwed into the engine. I **believe** that if that stud is backed out, the sensor you have will screw into the resulting hole. But also be sure the connectors are the same.

Thanks Boomer! The connector is the same which is why I am so confused with the other end. I don't want to make this project harder than it should be, but if it's simple enough to screw out the stud and this fits in there perfectly, then I can do that. BUt i want to be sure first.

I'm about 80 or 90% sure it will work. But see if it fits "hand tight" before torquing it down. Also be sure that there is clearance above the sensor - doesn't the plastic cover come down close? I'm not near any diagrams at the moment, so not sure. But I would try this before buying another one.

This is the knock sensor for the AJ26 engine.

@ gocallahan The 98' is fitted with an AJ26 engine, have you got to the knock sensor on your engine to replace it yet?
Have a look here at the knock sensors picture of a similar engine,
https://www.jaguarforums.com/forum/x...-thread-61113/
Post #5 has pictures of both the early sensor installed (the one you have) and later type.
Like Boomer says, it will fit, so no worries.

Great! Thanks guys!

I had intermittent knock sensor codes, sluggish performance and restricted performance coming on in my wife's 99 XJ8. Finally figured out it was cheap gas where I was paying for 93 octane and getting 87.
Switched to Shell and the kitty purrs again.

Isn't that fraud? What company, so I stay away from them.

thx

Thank you so much for posting this information.

With the comprehensive pics, I will be able to do this job with my local Mexican mechanic whose English is non existent and whilst I think my Spanish isn't bad, it doesn't include mechanical terms...

Plus Stymie is sending me some parts.

I have had it happen at both Valero and Citgo.
Since I live in Texas there is no consumer protection. The gas station will blame it on the truck company and the truck company will blame it on the refiner and on and on.
They caught one chain here and figured they stole millions so the gave them a fine that was a pitance of what they stole.
It can happen at any station so always be wary if you start getting poor performance or codes about 10 miles after a fill up.
Cheers