I know this is a much discussed matter, but my CEL just came on after a lengthy road trip and I'm 4 hours from the nearest dealer. I want to have Auto Zone or other local auto parts stores hook up their OBD device but I'm afraid of the battery discharge problem I've read about on here and am wondering if their equipment will actually provide the reason for the CEL. Does anyone know if this method will explain the reason for the CEL and if the battery terminal method becomes necessary, will it be necessary to reset things like the seat and window memories, trip computers, etc.?
Thanks to anyone who can provide any advice.

 

This may not help but is worth a try. Check the gas cap. If it is not sealing correctly it can cause a CEL. Remove the cap and run your finger around the gasket to make sure there is no dirt that may be causing it not to seal. Then put it back on and make sure it is tight.

 

I’ve kinda formed an impression that this draining stuff is less of an issue with newer cars like yours. Mine is newer as well and I have not experienced any such issues with at least 2 devices so far. I am still careful to back out of menus and shutdown the device cleanly just in case.

I have the feeling Jaguar quietly fixed the issue, but you if you are going to have them do it I would just mention your concerns to the guy and asked that he be extra careful to back out of the menus on the device and shut down the device properly to avoid potential issues.

Good luck

 

I had already checked and double checked the gas cap, but I took your advice and ran my finger around the gasket; it was squeaky clean and the CEL is still on so guess I'll have to try having the codes read.
Thanks for the tip though.

 

I'll take your advice and proceed to Auto Zone this AM. Thanks

 

I don’t have a sense if Jag fixed the O2 sensor issues on the newer cars, but that’s probably the most frequent CEL cause, which isn’t critical and Autozone etc. can read and interpret the O2 codes. It’s possible the CEL will clear itself if you keep driving it. If the CEL isn’t flashing, then it isn’t considered urgent.

As for the possible battery discharge, I’m sure you know how to recognize it (red hazard triangle still illuminated 20min after shutdown). And correcting it only takes pliers, crescent wrench, or socket wrench, etc.

Edit: I posted after you. I believe I had Autozone scan my car years ago, no problem.

 

Update: AutoZone scanned it and returned a "P0173 fault in the Bank 2 Fuel Trim for a predetermined period of time."
My research suggests I don't drive it as it may severly damage the engine. I have a query into my dealer asking for advice.

 

P0173 is a generic OBD fault, your car may have more specific faults if scanned with an actual JLR tool. Which engine? The 4 cyl doesn't even show P0173 as an option in the PCM.

Assuming you have a V8, it looks like an O2 sensor is failing, but post-catalyst. Usually won't affect anything but emissions.

I wouldn't be afraid to drive it home like that.

 

I had exactly the same problem/code with my 2019 SVR. Bought the car last November, and during the 250 mile drive back home the CEL came on after stopping for a short break. Continued home and took it to the local JLR dealer next day who diagnosed it as P0173. Dealer thoroughly checked the fuel cap, vacuum system, MAF, O2 sensors, etc, but couldn't find any obvious fault so recommended I run 2 doses of Techron Fuel System Cleaner through 2 fill-ups to clean out the injectors, which I duly did. Following this I did a lot of short (max 40 mile) trips and the CEL stayed off, however on the next long road trip the CEL came back on after stopping for a short break following a 100+ mile run. Once again it threw up P0173 code. Long story short, both catalytic convertors had to be replaced (had to wait a month to get them from the UK), and now the CEL issue has finally been cured. I was initially terrified over what would have been a $9,000 bill for this job, but fortunately there is a USA federal mandate that states any manufacturer must replace CC's free of charge if the vehicle is less than 8 years old, so in the end it cost me nothing.

 

There's 8yr/80k mile warranty on emissions components, so even the O2 sensors at that point would also be covered. The SVR tends to cook the cats due to the aggressive overrun popping, it dumps too much fuel and hurts them in the long run.

 

Update: My car was picked up yesterday for transport via flatbed to a facility in Wilmington, NC as they too advised against driving it.
Inasmuch as I purchased the vehicle from the then dealer (I say then dealer because they no longer sell Jaguars; but they will continue to service them as long as they are in warranty) in Charleston, SC I was shocked when Jaguar Roadside Assistance informed me that they would not cover transporting the car to Charleston because Wilmington was the closest facility. Here's the rub: My vehicle had been transported to Charleston previously when it lost steering because rodents had chewed the wiring from the steering assembly; so I'm wondering if Jaguar is punishing the Charelston facility because they are dropping the Jaguar brand.
According to Google Maps the distance door-to-door to Wilmington is 99.9 miles and to Charleston 95.5 miles--but I'm not paranoid!
PS I will probably send Jaguar coorporate a very strongly worded letter.