Hi! I’m new here but have been a member of another car forum for two decades, so I know the “use the search” rule and I think I found my exact issue, but need some advice. I pulled this quote from a different thread, and it is my EXACT issue:

Yes. This is it exactly. About 75% of the time this occurs <10 minutes into the drive. My wife will NOT drive the XJR anymore due to this issue (suits me fine haha). But the only action necessary to correct the symptom is to pull off the road, shut the car off and then re start it. Presto! Everything is fine.

Now, this doesn’t cure the underlying fault causing the limp home mode to activate and I would like to have it solved. I am not mechanically inclined, so I cannot do the work myself. So here’s what I ask you kind experts for:

Could you please give me a description of what I can ask my Jaguar dealership or an independent specialist for in the way of parts / labor to get this specific issue solved? While I am happy to spend the money to get the XJR working properly, I have zero interest in taking it to a shop and letting them throw ill selected parts / labor at the issue until they blindly discover the remedy.

So, plainly: What part(s) do I need to buy, how much will they cost and how many hours of labor am I looking at?

Really appreciate the help. In return I’ll come back here and report for future internet searchers plagued by a similar issue (seems somewhat common).

 

if you try to self diagnose your car no self respecting shop will take that work

read the dtcs google the service info learn how the aj26 and 27 throttles operate then diagnose it yourself. otherwise mouth closed wallet open

 

This is a quite common issue on a X308 and i went through the whole process.

Let me give a short suggestion first. Go rebuild your TP. This is a normal permanent solution. Visit the link below.

https://www.autoecu.com/jaguar-3/

Second of all. While you may be a very loyal customer to the dealership religiously believe they can fix everything for you and of course i have no doubt you can afford their labor rate. I can tell you i have friends working as mechanics at many big car brands dealerships. They DONT fix nor repair. They only replace parts. With parts from old vintage cars..they will just quote you a ridiculous Price. They will rip you off.

That's we form our own brotherhood here. Good Luck and welcome to the group.

 

Is it an early (AJ26) XJR or a later (AJ27) version?

 

Thanks very much for the clear direction. So you’re recommending the $389 rebuild option (doesn’t indicate supercharged vs non-supercharged)? I was thinking I might buy a spare to install and then also have this one rebuilt if this is a common issue?

Looks like the throttle body for the “supercharged version” is a bit more expensive at $1049 vs $889. Thanks again for the help!!!

 

Thanks for the question, according to my google results a 2001 XJR will have the AJ27s engine which is the AJ27 supercharged.

 

being a 2001 car, yes. you have the AJ27 engine.

 

this is my old post about the TP issue

https://www.jaguarforums.com/forum/x...orting-237407/

 

I have a supercharged AJ27 Throttle body sitting in my garage looking for a home...

 

We're all going to face this issue, mine was after the rebuild and finally posted a P1121 - infuriatingly intermittent, mine finally wouldn't come back online after a hard reset...
So a spare was fitted, touching wood it's good for a while.

Jaguar themselves do not have new throttles on stock.

It's the TPS/TPPS sensor tracks wearing out, some have fitted a China copy of the Denso TPS.
I like the option you USA guys have of just sending one off for a rebuild, I may need to speak to them about international shipping.

I've a number of AJ27 throttles in bits, the only difference between the NA & SC is a coolant hose for cold starts on the NA and a blanking plate on the SC.

 

I just did a quick glance over your thread as just woke up

There seems from reading others a difference in wire colors between a 2001 TPS or MAF sensor over the X308 earlier years , may be a wiring mix up

There are 3 wire DC voltage values that are the return signal to the ECM

The values are at idle and go up on throttle up

This is a test to see if the sensors are alive and on the proper path to the ECM and not so much a calubraion

A sensor value may be missing or out of expected range and rejected going into limp mode

Editing

For a 2001 AJ27SC engine :

PPS1 / 0.6 volts DC / Black wire

PPS2 / 0.8 volts DC ( notice the difference ) / Orange wire

MAF / 1.2 volts DC White / Green wire

TPS1 / 0.6 volts DC / Brown wire

TPS2 / 0.6 volts DC / Green wire

This notation at the bottom of the wiring guide figure 4.3 rhat needs clarification, . you can see the difference on earlier wiring guides

NOTES: * Early production vehicles have wire color codes that are different from that shown. Use connector pin numbers for wire identification.

 

Why wouldn’t you keep it as a spare? How much are you looking for?

 

My SVP was totaled a while back. I got the car back and dismantled the whole thing with a dream I would build/rebuild another. Unfortunately not in the cards at the moment. Moving so need to get rid of stuff
PM Me for a deal

 

Before you go through the throttle body rebuild process, remove the pedal position and throttle position connectors. Clean them with spray contact cleaner and re-attach. If you have dielectric grease, put some of that in the connector too. I had the same problems with my first VDP and got the body rebuilt only to continue to have the same issue. If it went into limp mode and re-starting did not correct it, I would pull off the PPS connector, reattach and the car was fine for some while. Ultimately, I ended up replacing both connectors but it was the PPS connector that was the problem.
This does not imply that you do not need the have the body fixed; the others on this forum are very knowledgeable and helpful. It would be hard to keep our cars going without their help! Best, D

 

Mine used to do that, disabling the cruise control (even when I wasn't using it but the red light was on by the gearstick) cured it. Apparently that proves it's the TPS that comes with the throttle body, not the replaceable one on the end.

I got a second hand TB of a NA car, swapped the plate on the back for the coolant hose/blanking plate and I think the throttle cable bracket. Everything else is the same.

 

The only difference between the SC and NA AJ27 throttles is the Air Assisted Injection system.(NA only)

The air valve on the NA throttle can be removed and the 'blanking-plate' installed for the SC engine.

 

Just wanted to update with some happy news: the mechanic said the throttle body was “filthy”, they uninstalled it, gave it a thorough cleaning and reinstalled.

said they could not duplicate the error after three separate test drives 15-20 min each. Fault usually hits around 10min.

wife will pick up tomorrow, I’m traveling but I’m excited to test drive.

 

The issue is back after a cross country move. In the span of a 6 mile drive it happened 5x.

 

If you’ve done the above suggestions, I’m going to recommend either you get 1) a good used TB (Col. Sanderz is a good guy to buy from), 2) buy a new aftermarket TPS (search eBay) or 3) get your TB rebuilt. I’d suggest 1 for the fastest potential remedy.

 

yep. I sent him a PM this morning. I’ll have it swapped and have the old one rebuilt to keep as a spare.

thx for the suggestions you’re right on.