Here is where I’m at.

2005 XJR, 125k miles. Purchased about a month ago. Minimal drivability issues for around 2 weeks and roughly 100 miles.

Where I’m currently at: Driving through town Sunday I got the dreaded red light with error message Engine Systems Fault and experienced when I believe is referred to as “limp mode” where I was unable to exceed ~1500rpm / 10mph.

I turned the car off and ran a scan (w/ iCarsoft). I had some already noted miscellaneous codes for things I didn’t really care about still present, but the brand new code that I presume related to this incident was: P2118 - Jaguar Throttle Actuator Control Motor Current Range/Performance.

I sat for a few minutes and started it back up. Still restricted. I turned it off, sat for about five minutes and tried again. Started up and I got to my destination.

3 hours later I left to return home. Everything was fine until I was 3 blocks from home. This time, no sitting fixed the issue. I “limped” the 3 blocks home am parked.

Once home I was a little frustrated so I just disconnected the battery for a bit and let it sit. At this time, when the car starts up it goes right into restricted performance. I say when because half the time it feels like the ignition locked me out. Key won’t turn. This might be a separate issue as the keep has always been really difficult to turn to start even on good days. I don’t believe the steering wheel lock is causing this but I will try again just to make sure. Also, moving the shifter slightly out of park creates an electronic audible beep. Again, might not be related and might always do that I just haven’t noticed.

Here are the basic facts. I will try not to embellish or place subjectivity. I realize that my actions may not have been ideal, but I feel it’s important to put aside my pride and acknowledge my potential lack of judgement. I’m here to fix a problem not make myself look good.

Battery is like new. Using the scanner I identified both charging and cold voltage is well above acceptable range based on information found here.

Thursday of last week (3 days prior to incident) I installed a Mina intake and filter along with the slightly larger Range Rover intake manifold.

First Thought: During this job I also cleaned the MAF with 91% isopropyl lightly misted through a spray bottle. Disclaimer: I realize that MAF cleaner exists and is obviously the right thing for the job. I just didn’t have any handy and the parts store was closed. I often use this isopropyl spread for electronics. Maybe I trashed the MAF? Appears to be the stock sensor.

Second Thought: Before installing the air system I used throttle body cleaner on a microfiber rag to clean the throttle body in situ. I manually opened the butterfly with my hands when doing so. Perhaps I damaged the throttle body somehow? Some of the research I found directed to an electrical piece on the TB.

Third: First fill up was the same day I finished the intake. 90 octane ethanol free. Maybe some part of the car doesn’t like this? Octane too low?

Other than those two things, I really can’t pinpoint what may have occurred. I’m an old school shade tree mechanic so it’s hard for me to not go out and start replacing questionable parts, simply due to the cost associated with doing so. I used to go out and drop 50 bucks on a handful of parts and just do them all in one go when I had a problem. It cost effective these days.

Any help or insight is appreciated. Perhaps some way to test the electronics of the throttle body? Pulling it is easy enough. Should’ve done that to clean it but was feeling particularly lazy.

 

The throttle bodies of these cars are a bit on the sensitive side. After manipulating the throttle plate slightly in removing it from the car mine threw a P2135 code and I ended up having to replace it. Can't hurt to check the electrical connectors for voltage and ground. You can also check for open circuits to the ECM harness but you'll need a 5-point security bit to get the ECM harness off. Also check to see if there is water buildup in the connector housing -- there's a TSB for the S Type R's for water buildup causing throttle issues. Good luck with it.

 

Just a suggestion; when you have disconnected the battery in addition to resetting your auto windows I believe you need to switch the ignition to position 2 and then press the accelerator smoothly all the way to the 'kickdown' détente 5 times in order to reset the Throttle Body motor?

 

To EsRay's point my brand new throttle body threw an error code as well until I reset it using the kickdown procedure.

 

I feel like I’ve head this before, actually. Just to make sure I do this correctly, are you suggesting:

1.) d/c battery (just to start fresh)
2.) slowly apply accelerator pedal until the first “resistance” point, then the rest of the way to the floor
3.) repeat x4

BRB, going to go give it a try.

 

I kept having a limp home issues and resolved this after I heard that there was at one time a TSB about a protective rain shield over the TPS sensor that will get moisture drip down the wires into the connector. I mainly had an issue every time it rained or I drove through a car wash. I wrote a thread about this back on 10-24-2018 and some people thought it wasn't my problem, but ever since I did this I have not had one problem with a fault code restricting my performance. I can't figure out how to link it but here is the caption and a link.

DefaultP2135 FIX; X350: Engine System Fault
https://www.jaguarforums.com/forum/x...-fault-209761/

Hope this helps!

 

Don't disregard other codes. They can help to pinpoint the possible causes even if they seem to be totally different systems. Do you still have them?