Ok, so I know the answer is probably yes, in general, but here is a more detailed description that hopefully explains my skepticism and can also illicit some suggestions as I am scratching my head on this one.

I am working on my 2011 XJL SC. 107k miles. This is an auction puzzle for me. I know very little about the status of this other than it is not salvaged, I got it for a steal, and there are some cosmetic issues, including some melted left rear plastic pieces that appear to have come from the jag being next to a heat source but def. this car was never on fire or touched with any flames or anything. I am 100% sure on this.

I have had it for about a year, sitting in front of my garage, where it has sat since it was delivered. When it was delivered, it was started and was running for at least 20-30 minutes while we worked to get it off the trailer as the rear suspension was not working. (This will be important for later).

I have been very busy the past year, including tearing my calf in February and being indisposed for 2-3 months because of it. Finally got back around to working on it this weekend and my goal was to fix the rear air suspension and start it so that I could move it out from in front of my garage door to work on my many other vehicles. Oh, I forgot to mention that I also have a 2012 XJL SC with ~79k miles on it that I also got from another auto auction for a steal. Will be using it as a donor and it has already come in handy. I diagnosed the air compressor as being locked up on my 2011 and swapped it from the donor and that solved the suspension problems.

I started it up and it sounded decent and started right up. It was idling fine...for only about 60 seconds or so, maybe 2 minutes. I had to go close my garage door to keep the CO out as the car is backed toward the garage. Then, it just died. It wasn't like a sputter, rattling, die as though it was a fuel problem and it was running out. It was more like it was cut off with the button. Then I was left in a crank (normal sound/speed) but no start.

I do have SDD, v, 131.03 and am still a beginner with it, but comfortable with it and have figured my way around so far. I also have an X-Tool D7 that I also use for comparison.

Here is the info that I am getting out of SDD and the D7:






I am unable to clear any of these codes. I checked all of the fuses in the Central Junction Box (Passenger, behind the back seat) and the junction box in the boot. They are all still in tact. I ran all sorts of things in SDD, such as a vehicle reset, an on-demand self-test (but for PCM only - couldn't find it for the BCM). I also happened to see a report in the Extra section of SDD that basically is saying that many BCMs were returned under warranty that were actually fine so be sure to diagnose properly. I did run a fuel pump pressurization from within SDD and I didn't hear anything and I have the rear seat completely out. I know I should, but if the module has shut itself off to protect itself, wouldn't this stop the pump from working?

Now, I know that it is trying to say the BCM/CJB has an internal solid state module that is not working. At least I think that is what it is saying. However, my problem with that is...how would it just "go bad" suddenly. Remember, when it was delivered a year ago, it ran 20-30 minute and then I started it successfully today and it ran for 1-2 minutes and then just died. I suppose anything is possible, but I am a highly logical person and there doesn't seem to be a slam dunk case that the module is bad and needs to be replaced.

That being said, since I have the donor, I do have a spare CJB/BCM, but I don't like throwing parts PLUS I'd want to figure out what might have caused this problem in the first place if indeed the original CJB is bad. Also, I know I'd have to program the donor and though I am certain this can be done in SDD, I don't know how to do that at this moment in time. So, does anyone have any suggestions?

Mike

 

OK, so I have been tracing this crank, no start down all day. I like doing this stuff bc the reward is great, but I am stuck at the moment. I discovered that I don't think the central junction box (passenger fuse box) is probably not bad. I also discovered that my problem is fuel delivery. When I spray starter fluid in the air intake duct while my wife is cranking it, it will start-ish for a few seconds until the fluid burns off. So, I have ignition. When I backprobe the power and return at the fuel pump and turn on ignition, I get 0v, so my next step back would be the fuel pump driver module. Now, this connects into the central junction box so this DTC may very well be referring to the fuel delivery driver module but I cannot be sure until I can get at it and test it. So, therein lies the problem...where the heck is the fuel pump driver module on the 2011 XJL? The service manual is saying it is under the car over on the righthand side under the passenger seat area (which would of course be below the fuel tank). I don't see it anywhere. I asked ChatGPT and it says left side. I haven't gone to look there yet, but seems odd it'd be over there since the pump is on the right side. Does anyone know where this is located?

 

The module may be fine but the pump is suspect - they hate sitting unused.

 

Oh, I have seen some terrible engineering in my day, though usually am not in the seething rage camp against them, but this nearly took the cake. I found this driver and it is one of the worse places I have seen an electronic. I can't even really get a picture, so I will have to try to explain. It is underneath the car, out the outside of the cabin. It is slightly off the to the right hand side but all the way up, attached to the floor pan about where the luggage compartment meants the back of the back seat. So, yeah, directly above all of the suspension cradle, just to the outside of the evap/fuel vapor canister. It is nearly impossible to reach either from the wheel well or from underneath and even if you could somehow manage to get it unbolted, I don't see how you can fish it out or put one back. The only way I really see of doing it is to drop the suspension cradle.

That being said, I had decided to skip that and test the rest of the components upstream to see if I could find another source of trouble. Honestly, I felt like I was wishful thinking at this point. Fuse was good but then as I was looking at the wiring diagram, I noticed that the relay was labeled R3. Now, I had thought that the R3 relay was in the passenger fuse panel, you know...next to the fuel pump fuse. However, looking at the diagram, I noticed it said it was in the luggage fuse panel. So I was looking at it and I was skeptical because I had a relay in R1, R2, but R3 was empty. Since this car had run for 20-30 minutes when it was delivered, my thoughts never went to a misplaced or missing relay. So, I then assumed that perhaps my wiring diagram was slightly different than my vehicle, which I am finding is the case on a few things here and there (but not with the wiring...up until this point, I thought). Therefore, I thought the FP relay was the one next to its fuse in the passenger panel. When I went to swap that with my parts donor, just for s's & g's I checked out the luggage panel in it. HOLD UP...I immediately noticed that this one had a fuse in R2 and R3, but NOT in R1. Still, the parts XJL is a higher trim level and I thought maybe that difference is because of the trim level. However, though I was sure it couldn't possibly be the problem, I moved the relay from R1 to R3. I went to start it, quite smugly I might add because there was just no way. And then....it started right up!

So here is what happened. To start, I have some pretty crazy adult ADHD (diagnosed, not just OMG, I am culturally adhd), but on things like this I am usually pretty good about putting things back where I pull them from. However, though I didn't remember at first, I HAD pulled those relays and tested them all when I was troubleshooting my air suspension not working. At the time I didn't really have the wiring diagram yet and wasn't sure which relay went to what. I guess I had to have just put them in the wrong spot (shifted them all up 1), which explains how it ran last year for half an hour, and also only ran for like a minute a few days ago. I surely laughed at the simplicity of it all, happier than anything that it wasn't that fuel pump driver module. All was not lost though as I got the opportunity to get better at wiring diagram reading and learning more about my XJ so overall it was a positive for sure.