I think my TB finally gave up. I got the usual "engine system failure", "DSC not available", "Park brake failure" trio along with CEL and code P0121.

How hard is it to replace the TB? Any tricks besides "follow the JTIS"?

 

You have my sympathy ...seriously im sorry to that. I say that because 2 months after buying my 04 XJR my throttle bodie had to be replaced and i will never forget the bill that my jaguar *********** gave me $2654.32 I was still new to the game so i just didnt want anyone working on a specialized car ( XJR ) that didnt have the direct experience with the job itself. My advice shop around. My feelings are still hurt 3 years later with that bill.

 

Thanks, Cincinnati.

My understanding is that the major portion of the bill is for the part itself. You can find it online for a much reasonable price, however my dealer won't install a part I didn't buy from them - bummer.

 

If I recall, we have some active and knowledgeable members in your area. Perhaps one of them can put you onto a "prefered" local independant Jag mechanic who will insall the aftermkt. TB for you.
If one of these forum members can help, now is the time to chime in.
Also, you can make an appeal in the NW Area of this forum for recomendations. Shoot, I bet somebody else has already done so. Do a search in NW Area section. There is always a way to save bucks if you have the will and time.

Okay, I'm back. Just did a search in the Western section of this blog for "Seattle". There are a number of recomendations. Go for it.

 

I second the recommendation to find an independent shop--the other place you can look is on the Car Talk website in the Mechanics Files section.

 

The JTIS procedure is relatively simple:

Remove air hose.
Disconnect electrical wires.
Remove 4 bolts.
Disconnect coolant hoses.
Discard gasket.

Install in reverse.

Sounds simple enough for me to try and tackle it myself.

 

I don't have this problem (touches wood), but where would be a good source for the TBs? And would used or reconditioned be any use?

 

Try jaytanindustriesinc.com. I heard once they deal in this sort of thing.

 

Turns out one of the connectors on mine is missing the clip. I could remove it by just pulling lightly. I'ts possible that is the problem with my car.

 

I like that name for those cats dealership

 

The code you mention is not for the throttle body, it is for the throttle position sensor. The test for this start with reistance measurements. It is possible that the harness is the problem in these situations. This is yet another case where detailed information on code retreival is necessary for proper diagnosis. I went to Alldata and there is a series of detailed tests for this problem, and replacement of the sensor is the last thing to do.

 

Jaguar has a TSB for code Po121 from 1999 to 2001 however we found a few cars outside that date that had a problem. I would pull the TB plug and clean and tighten the contacts and see if that works. I hate to you spend the money on a TB when all you needed to do is just clean the contacts. If it does not work then take the next step. This is a link to my page that addresses the situation. http://www.gusglikas.com/AutoRepTB.htm

 

My apology to the forum and all members for not respond sooner, my XJ6 TPS is fix . It was not the TPS at all do to the lack of use the throttle body shaft got partially size, I remove the TB I use injector cleaner solution ant an ld tot brush and now works good Thanks every body

 

I just got the infamous P0121 code along with the idle to the curb. I put in a request at www.CanOBD2.com and while they don't have the info yet, it should be availble in 5 bus days. They'll want $14.99 for it. You can look at a sample from a Ford pickup to get an idea of what is covered. In the JTIS CD for 1995 to 2004 Jags it gives the test procedures for code P0121 along with P0122 and P0123. All of these should be checked for wiring problems first. If you have the CD, go to #3 "Powertrain and go down to 303-14B and you will find the DTC index and "Pinpoint tests" and item "D" covers codes like P0121. My P0121 came just after a road trip and the day before, I had one of the car washes that included "Under car" wash. In CA we don't have salt and this car is aluminum. So I,m looking and testing.

 

You need to look at you TB plugs. Clean them and make sure the connections are tight. http://www.gusglikas.com/AutoRepTB.htm If you use this link you will see the list of OBD II codes and what they stand for http://www.gusglikas.com/images/Auto...%201997-99.pdf I hope this helps!

 

Yes, I looked at the plug already and WD-40'd it to clear out any possible moisture. In case folks don't have a wiring diagram: You'll find 4 wires connecting to the TP sensor. #1 BG is the ground. #2 R and #3 Y go back to the ECM at points P11-75 and P11-076 respectively. #4 OY is the power from the ECM. My next step is to check resistance to ground, then power across #1 and #4 using the back probe method. My Equus 3130 gives "Live" data and so I can see what the throttle plate position is.

This was strange: I was running the RPM's up while in park to watch to TP "working." It engine had a missfire that didn't generate any codes. Running her up in drive in a "stall" test there wasn't any missfire. It is a 2004 XJ8.

 

Mine does too and no codes. If I remember it was around 1000-1200 RPM.

 

Here's my latest. I've had a sick kid and so my time with the scanner and the under hood time has been limited. Today I was going to clear out the codes and see if working on the plug had helped. First I wanted to get an RPM and timing readings for the miss problem in park. I noticed that the check engine light was off and the P0121 was gone( I didn't clear it ) and when I tried watching the "Live" data, I didn't get the miss until over 4000 RPM. I didn't have fine enough probes to get readings from the TP plug and so that is for another day. Next comes test drives. I am not so sure that # 1 wire is (-) and # 4 is (+). I will get that later. A good multimeter won't care and it will show a (-) if the leads are reversed.
REMEMBER CHECK THE WIRING BEFORE REPLACING THE THROTTLE BODY!!!!!

 

I finally got to test drive today. I hooked up my scan tool (Equus 3130) and put it on "Live" data. I drove around for a while and made a few "jump on it" takeoff's to run the throttle plate through the range. I was able to get 100% throttle opening and so far, so good.