Alright finally caught this code thing that has been dodging me for ages. P0121. Yeah finally got that bugger and the timing right to go into limp mode at the mechanics that was ready with a reader. Took weeks to get the timing right and another half day to get it to "Act up" once at the shop so we can at least get a code.

P0121. Throttle position switch. Now before one or two people start telling me every thing under the sun that I already know let me go ahead and share what I have already done to save time. I've checked the battery(perfect condition actually a lot better condition than I even thought) , it isnt the brake switch, no the brake lights never stopped working, it isnt depended on cruise control on or off, etc. Rarely use cruise control in the first place, it happens only sometimes not all the time, no check engine light, but usually occurs when coming to a stop, had TB cleaned, checked all connections, none are loose was loose came loose worked loose looked loose and not dirty. And all of the other common sense stuff that anyone that ever turned a wrench before would have checked have been checked throughly. Now that we got that out the way... Oh yeah did I mention the TB already been cleaned and wire connection checked for tightness already and no CEL?


I did read about the connection thing with the tin in the connector causing problem with the gold pins in the TPS. I guess it's another one of those wtf design things. Anyways, one, is there a place to order the connectors. The dealership here say that have no part number for it. And two, is there a way to get the entire wire? As I'm not exactly sure if it's the TPS which may require a new throttle body or the tin to gold thingy at this point it would be useless to get a whole new throttle body if it's going to be gold pins again with tin in the connectors and that is a pretty penny to spend to not fix a problem. Then again, cutting wires like described in the literature I came across seems like just asking for more diagnostic holes. Next thing if that dont work then it will be "Oh maybe the wires are touching" "maybe they wasnt twisted right". "maybe they wasnt twisted to the right with a slight arc downward" and ect. No time for that nonsense. Is there a way to buy the entire wire with the gold connector say for the 2003 XJ8?

And from what I gather, if there is wire connectors sold whole, and it's the throttle body that is trouble, where are some good places to get a new throttle body or a good rebuilder and what is entailed in the rebuild and fro mthe prices seen what actually distinguishes it from an used TB? Meaning do it come with a new TPS since usually this is what is causing the entire TB having to be replaced.

Oh and of course take ya time. Already bought an 07 BMW (more online support and more familiar with design). This cat is on it's way to storage until I decide what to do with it and or come across a W220 to trade it in for fixed or not. Prefer fix so it can go out with dignity but will settle for as is if this solution continues to elude me due to non-available of parts or requiring some bootleg wire cutting.

 

We had our 2001 XJ8 Throttle Body rebuilt last August (2012).
Ebay listing for Rebuild service:
1999 00 01 2002 Jaguar XK8 99 03 XJ8 Throttle Body Assembly Repair XW939E926AE | eBay

Here is information I posted back then:
There are few electronic shops that rebuild them at reasonable prices. I just had my throttle body rebuilt this week (2001 XJ8) at ATE (Auto & Truck Electronics) in Rodgersville, Tenn for $326. They are also known as ASI (Automotive Scientfic Inc).

This is the other information I posted in late August 2012 - here is the weblink (look at post#1):
https://www.jaguarforums.com/forum/x...rebuild-79462/


Early October 2011
I cleaned the throttle body butterfly and a couple of the sensor plugs and connectors (with throttle body spray cleaner and electrical spray cleaner).
This resolved the P1121 DTC fault. But after 2 weeks, P1122 and P1642 faults started.

These were cleared by replacing the TPS connectors with new gold TPS connectors kit - part numbers are for 1 wire - (need 4 wires replaced).
Part# LNG 3956AA (each cable) & LST 6754AA (Convoluted tube) - Nalley Jaguar $60.36 (Nalley out of business - now business at Jaguar of Greenville in South Carolina)
Update (3/22/13) - for parts inquiry online - Use Part# LNG3956AA & LST6754AA - need 4 of these for each part number - total at Jaguar of Greenville will be around $75 - $80.

The TSB 303-58 on TPS connectors says models 1999-2001 XJ series and 1999-2001 XK range.
Since your jaguar xj8 is 2000 year model, you probably should inspect them and get the gold tps connector kit if they have not been updated.

Jim Lombardi

 

this sounds like the TPS tracks are worn. Plugging an obd reader in and scroll to throttle position (in %) then watch it rise and fall with very slow pedal movement along with an extra set of eyes on the butteryfly can confirm if it's goosed.

Jim's info is valuable, get the throttle rebuilt. The link lead on an 03 is already updated. You might have spotted my posts on the 1121, ended up using a throttle made up out of low miles bits.

 

This would be worth a gamble... $65

jaguar xj8 intake throttle body wheel sensor accumulator look

 

That's an AJ26 it won't fit - the car's an 03. It needs the AJ27 TB

 

My bad- sorry.

 

Hi
Looks like blackwolf560 has a 2000 XJ Van Plus listed in his profile.

I think he mentioned 2003 TPS wiring to see if he could buy part of the harness that has the gold connectors to Throttle body wiring (2003 XJ) because he does not want to splice into the present wiring.

TPS is the Throttle Position Sensor - It interprets throttle position and movement to identify idle, acceleration and full-power demands.

I do not know if it is possible to use TPS from an AJ26 Throttle Body in an AJ27 Trottle Body. You probably would not to do it anyways since there is no assurance that the earlier TPS are not without their own issues.

Per the DTC Summaries Vin Range from 812256 to 853925 have A26 V8 Engine and Vin Range from 853926 have A27 V8 Engine.

Per the JEPC (parts catalog) here are the throttle body part#:
now C2A1470EK (C2A1470) - Vin Range from 812317 to 853925 (AJ26) $1189 new

now C2A1444 - Vin Range 853926 to F59525 (A27) without supercharger $1904 new
now C2A1445 - Vin Range F00035 to F59525 (A27) with supercharger $1720 new.

Jim Lombardi

 

good very good information here.

Although I probably will end up gettinga rebuilt or low mileage updated TB, still, the thing that bothers me and seem to nullify the point of doing the above mentioned process is the plugs.

if the materials of the plugs also can cause problems, although at this point I'm pretty sure it's directly the TPS switch on the fritz at random ( since my last posting not a single issue not even a code, go figure.), then if the new and or rebuilt TB will still have gold pins and the plug have tin, then the problem has great possibility of still peristing it would seem especially if come to find out that the it was the wires to begin with. Cutting into those wires especially in a car where these compenents are sensative to voltage readings, and lack of Jag techs here (there are none available at the sole Jaguar/Audi/Subaru dealer), it seems very high risk to cut wires of that sort especially one that can send the car into limp mode. Meaning I probably will have to find the updated wires if I can sleep easy after spending this money and taking time to do the the repair.

 

blackwolf560
The updated wires means entire Engine management wiring harness.
Here is one on ebay for 1999 XJ8 (Engine motor bay computer ECU wiring harness):
Jaguar X308 XJ8 Engine Motor Bay Computer ECU Wire Wiring Harness | eBay

Note that this is one complete harness that from the ECM (Engine Control Module) to several other modules including the Instrument Cluster Module (Speedometer Cluster) that means removing the interior dash components.

I think the part number for the harness is LNG3350EB (jaguar classic parts uk sells a new one for almost 1500 pounds).

Ebay lists the used 1999 harness for about $270.

My indy mechanic works mostly on ford, honda, and GM vehicles. He took a picture with his cell phone phone before he cut any of the wires. Then he followed the detailed instructions and used the parts that came with the harness kit.
Nice neat job with no problems with the harness since it was repaired.

Jim lombardi

 

I would say if the potentiometer was bad you'd get ever more increasing faults.
I know Graham (GGG) had a sort of logarithmic series of faults when his sensor went TI.
FWIW my bet would be bad connections.

 

figures. Well the JAguar dash is not as much as a pain in the butt of a dash to remove in the MBZ W126 and W140s.

Plus another reason I dont want to cut wires is when I do sell this car, and a person looks under the hood and notice wire splicing in a car like this, they probably will walk not knowing it's an upgrade or if they are Jag fan, they probably will walk anyways not knowing the quality of the repair. Thus if I cut the wires I'm stuck and probably will lose more money than if I just bought a new wire harness and had it installed then if I cut the wires and try to sell a Jaguar with a splice job.

I know if I was looking for Mercedes and notice any spliced wires, that is automatically walking off the lot with no questions, no negotiating with price, no stop at go, go directly off the lot and go home. I had to do this with a few examples out here. Lot of juryrig mechanics out here.

Well hopefully to have work these things out. Then it's on to something else. I like the new Jags (2011-up) looks but geesh did they replace the suspension parts with diesel truck leaf springs? I think a red wagon have smoother ride. It's such a beautiful car though. How is those 2008-2009s? did they correct those little WTF were they thinking moments that appears in this car?

 

Actually I wish I could show you a before and after photos on the wiring splices that are not noticable at all after he rewrapped the harness.

Also the engine covers and the air cleaner that covers a lot of the throttle body makes very hard to view the harness.

The updated tps wiring and the rebuilding of the throttle body has enchanced the value of our XJ8.

It has been 6 months (8000 miles) now without any issues coming from the tps related issues.

Here is TSB303-58 on the gold tps wiring fix:

https://www.jaguarforums.com/forum/a...tsb-303-58-pdf

Update (3/22/13) - for parts inquiry online - Use Part# LNG3956AA & LST6754AA - updated tps wiring - need 4 of these for each part number - total at Jaguar of Greenville will be around $75 - $80.


Jim Lombardi

 

I see.

Now what year should I be aiming for in oder to get the updated wires?

And I checked out the rebuild sites but none mentioned about how long the process usually takes or what exactly they do to rebuild it and or what components are simply cleaned or replaced with new or used, or what parts are actually worked on. Very vague "ship it in and they'll ship it back" when work is completed.

Oh and where is the source to get these connectors? The ebay one list one for a 1999 which probably have the same connectors as currently on my car and thus wont work.

 

ASI also sells their own remanufacted throttle bodies on Ebay for $489

99 00 01 02 03 Jaguar XK8 XJ8 Throttle Body & Pedal Switch & TPS Quality Rebuilt listing on Ebay for $489 (remanufactured by ASI).

99 00 01 02 03 Jaguar XK8 XJ8 Throttle Body Pedal Switch TPS Quality Rebuilt | eBay

Here is what the Ebay listing says about the rebuild:
"This Throttle Body has been completely disassembled, Media Blasted externally, Protecting the throttle throat, The TPS and Pedal Switch & Air vale are disassembled and internal parts replaced, they are then reassembled and calibrated to OEM specifications, and the Throttle Body is then reassembled. Occasionally the TPS will need to be adjusted when the Throttle Body is fitted to the vehicle. We request that you replace the Base Gasket, We do not include this.”

After you received the remanufactured throttle body and install it, then you are required to send the existing throttle body to ASI.

ASI listing says free shipping - probably means they paid for all the shipping ie to you and from you.

I asked them about the 2 sensors on the throttle body (if they replace them with new ones) before I sent my existing throttle body to be rebuild. They said that the sensors would be replaced with new ones if the existing ones fail after being tested. Sounds like maybe only the internal parts in the sensors may be replaced according to the information I found in the remanufactured throttle body Ebay listing above.

based on the information in TSB (my prior posts), the updated wiring should be on 2002 and 2003 XJ model years.

The new gold TPS connectors kit can be purchase at any Jaguar Dealership parts depart - Jaguar of Greenville offers Jaguar Forum members a 15% discount and free shipping on orders of $25 or more. Kit was $60.36 when I purchased it - part numbers are for 1 wire - (need 4 wires replaced).
Part# LNG 3956AA (each cable) & LST 6754AA (Convoluted tube)
Update (3/22/13) - for parts inquiry online - Use Part# LNG3956AA & LST6754AA - need 4 of these for each part number - total at Jaguar of Greenville will be around $75 - $80.


Jim Lombardi

 

Update.


Still no blips thus far.


Alright probably check out ASI or probably just buy one of their ones that have already been rebuilt and order the kit for the wires.

Do Jaguar of Greenville ship? The dealership hear denies there ever wasa wire kit in existance. They sell the whole thing but no point in paying what they asking for, inflated price that it is even for dealer, if the pins are the same. They have no knowledge of the the pins being of different materials and stated that the ones from 1998-2003 were all exactly the same.

 

Still nothing to this day. It's as if nothing ever even happened. No light, no stumble, no anything. I'm like what the hell but hey, almost a month no issue, strange, very strange.

No luck on the wire set for 2003, plenty of 2000s and more than I can count 1998s and 1999s. I'll just wait and see. But from my research the 2003 Super V8 dont have much issues. No tranbox issues, no throttle body issues, or timing chain guide issues. Although I like the X308 but dont care too much for all these niggles, Im thinking about trying to track down a 2003 Super V8, that way I can can have the Vanden Plas package with a smooth ride and more power. If not, there are there usual choices available.

 

2003 Super V8 IS an X308.

 

Of course the 2003 Super V8 is an X308.

But they dont seem to have the timing chain problem, the transmission problem the TPS problem, the random electrical problems, the water pump plastic propeller problem, the plastic cooling system part failure (that cap that no one seem to know the name of, as usual, that is near the thermostat/water pump housing), the VVT problems, like the run of the mill 4.0 NA X308 has.