Late last year I had the car go into Failsafe mode with Traction Control and ABS faults. When I shut the car off and decided to limp it home, it cleared everything (including the codes) and never had an issue again. I've been driving it quite a bit since I got it out of winter hibernation in February, and never had an issue until I got a Failsafe mode again on Friday. I've been thinking it was a coil pack or some issue with the throttle body, but again, it cleared completely on a restart. Well last night I had a Failsafe mode again and this time the check engine light stayed on. Pulling the codes finally left a code that didn't autoclear so I can troubleshoot some: P0121 TPS.

After doing a bit of research there seems to be a TSB the connections (http://jagrepair.com/images/TSB/XK8/303-58.pdf). I think this would be a nice place to start. Is it worth replacing them per TSB, or just clean them and make sure the connections are solid? My other thought is to clean the throttle body while I am at it. If neither of these cures it, is there any way to get just the TPS, or am I stuck with a used throttle body with everything on it?

Does it sound like I am on the right track here?

 

Just read this thread: https://www.jaguarforums.com/forum/x...mp-home-42550/

If the simple stuff doesn't do it, I may need to drive to Omaha and have Jaguar scan the beast

 

I cleaned my plug several times and each time it prevented the fault for only a short period of time. All I did was postpone what I should have done the first time and that was to replace the contacts. You could have other issues but you would be best served by first replace the contacts and see what takes place.

 

I had the same thing happen about three years ago. I just cleaned and coated the connection with electrical grease. I may be just puttting it off but I haven't had problem since,

 

Did a little checking with Jaguar of Omaha and they found the part in the depot in Atlanta. Looks like part LNG 3956AA is $79, and 4 are needed?!?! Wow! I think I'm going to clean the contacts first and see once what happens.

 

Years ago, there was a problem with Motorcraft electronic ignitions.

The factory cure was to remove the distributor and change the trigger sensor and replace the amplifer. The customer would go away, and come back a few weeks or months later with the same problem.

That is, until I came along and being bad at retiming distributors, found another way ... chop off the connectors ... twist wires together and solder said wires. Presto ... no more comebacks. The problem wasn't the sensor, but replacing the sensor resulted in new connectors. The comebacks were caused by the "fixed" connectors expanding during the next bout of hot weather. No connectors = No problem. And much cheaper warranty costs.

If you *must* have connectors, there is nothing that says it has to be the factory connector. Just find a connector you are happy with, and splice it in.

 

Clean them first - if the problem goes away that's the problem.
If it comes back - that's another problem !

 

That's the plan for now, a nice cleaning. Just have to wait until I have some time next week.

 

The problem with the connectors is a compatibility (new contacts are gold plated) issue between both the male and female ends and Cleaning them is a first step in identifying the problem. I am confused with the price posted if I recall they replaced all of the contacts and the price was not per contact. I called Jaguar today and was told the total price was $119.00 with tax I am sure it is less from one of the parts places.

 

Well it seems this problem has come back with vengeance, so I will be ordering the gold contacts on Tuesday. One small issue, when unplugging the connector to clean it to get me by for a little bit, the catch broke. It still holds in place tightly, but I would feel better if it still clipped in. Is it possible to buy this plug from Jaguar, or am I forced to try the salvage route and hope that if I can even find one, that it lasts?

 

I don't see the connector in the parts catalog but there are places that sell new pigtails if you can figure out what more common vehicle used it.

Might be worth a look:
Automotive Electrical Connector Pigtails, Terminals, Tools and More

 

Just use zip clips - holds the connector in place better than the original locking tab IMHO. You may even find(outside chance) that it cures the problem.

 

I zip tied it and cleaned it with out a whole lot of luck. It lasted longer before throwing the fail safe, but that is it. I parked her until the parts arrive. I ordered from SNG Barrat, but they didn't have it in stock, so I have to wait a bit. Unfortunately I forgot to mention my forum member discount to save a few bucks . I ordered some wipers earlier and had them shipped to me (Bosch Icons) and halfway forgot until they arrived today. I threw them on and then decided it was so beautiful I had to drive the car, even if I had to limp it home. I took off to pick up my daughter from daycare, and left it out of sport mode. No issues either trip. I won't press my luck too much, but could sport mode have a negative effect on this or just mere coincidence? I'm inclined to think coincidence and won't drive the car a whole lot until the parts come, but it is nice to be able to drive it, even for a little bit, in this beautiful weather we are getting.

 

I am having the same issue with my 2000 XJR. About 18 months ago the problem first arose, and it was noted that the clip on the socket was broken. The solution was to clean the contacts and cable tie the plug on.
This lasted about a year, but then the issue came back. The contacts were cleaned, cable ties replaced, but this time it only lasted 4 months, and now I'm back with the same problem.

I'm looking into complete throttle body rebuilds, or second hand units, but I would love to hear how you go with replacing the pins. The more pics/info you can share, the better, as sometimes there are subtle differences between the XJ's and XK's that means a fix for one doesn't always work on the other.

 

I will do a full how-to with pictures. It will probably be easier for me with no supercharger in the way. Just two screws to remove the elbow and I have access.

 

Photos & TSB for P0121

Link JagRepair.com - Jaguar Repair Information Resource

 

Vert nice, Gus. That pretty much sums it up, just doesn't show the new contacts. I might show that if I remember, but the TSB illustrates that pretty clearly too.

 

Who are you ordering them through, and do you have to order 4, or does it come as a set?

I usually go through SNG Barratt...
SNG Barratt - The Ultimate Jaguar Parts Specialist

 

The connectors with short wires are sold SEPARATELY!!!!!!!

The part number is for EACH!!!!!!

bob gauff

 

Well... in that case, it looks like the best course of action is to solder new wires to the TPS, fill the socket with sealant, and install a generic 4-pin plug further down the line.

Should cost a couple of dollars, or even free, rather than $200!