I went to move the car this morning. It was last driven 5 days ago with no issues other than the P0447 EVAP canister close valve open circuit problem that Dale (crbass) and I hope to diagnose in a couple of weeks. This issue popped up in mid-July and since that time I have continued to take the car out for a weekly run of about 10 miles to keep it exercised....

But this morning when I got in the car and turned the ignition key, the engine fired up but would not run for more than a second or two before it shut down. I removed the key, waited a few seconds, and tried it again. Same result. I removed the key, waited perhaps 30 seconds, and tried it again. Same result. I never put my foot on the accelerator so I doubt that the fuel system could be flooded....

Rather than run the battery down (a Bosch AGM installed in July 2018 and still in great condition), I decided to grab my scanner and pull the OBDII codes. I expected P0447 and it was indeed present. But so was P0603, P0607, and of course the expected P1000....

I fired up my JTIS CD, went to the latest DTC chart (the 2004 model), and read that P0603 indicates an ECM Keep Alive memory error. According to the chart, this could be due to the engine cooling fans not running, and it could also be due to an ECM failure. There is a suggestion to try the ignition key in Position II for 5 seconds without starting the engine, then repeating that cycle 2 additional times. I will try that later this morning....

I saw no listing in my JTIS CD for P0607. Does anyone else see a P0607 listing for the 2006 model year in your resources?

Is there any chance that this new P0603 issue is related to the ongoing P0447 EVAP system issue? I would not think so but I value your opinions....

Any suggestions and assistance would be greatly appreciated....

 

Search shows this short thread:

successful-re-program-flash-2005-xk8-ecu-190075

 

Thank you for that information. Sure hope I do not have a failed ECM....

 

It might not hurt to try a hard reset.

 

Your problem is way above “my pay grade” and experience in this car, but I did have a ECM MOSFED problem on a BMW previously. Had to get a new ECM in the end as repair wasn’t feasible.

Hope you have better luck.

 

Over the years different folks have described a hard reset different ways. The most consistent seems to be to disconnect both battery cables at the battery and touch them together for approximately 30 seconds. Any consensus with that approach?

 

Reading that earlier thread, it seems like your ECM somehow lost its configuration and needs to be re-programmed. Looks like one of those somewhat extended SDD sessions, with a proper battery charger. You might have to call around and see if anyone can do this procedure for you (dealer, Jaguar indie with SDD). Maybe the original poster still has that spare ECM...

Other option, as per the code book, is that cooling fan, and that bypass procedure already listed above. Definitely the place to start...

For the hard reset, you need to bring the battery leads together somehow. Some have listed a lazy way where only one cable can be disconnected and brought over to the other one. From memory, it is the negative cable, so it makes folks nervous to bring that cable to the positive terminal. I'd say do what you are comfortable with. Also, I believe you need to also try and bring a load as the cables are together. Maybe try and start the car to really discharge everything.

Best of luck, keep us posted.

 

I had a phone conversation with Wayne (cjd777) this morning. He suspects that the still-unresolved mid-July P0447 EVAP canister close valve open circuit issue may be what is now choking off the engine at start-up and not allowing it to run. His theory is that my weekly 10-mile exercise jaunts during the past 5 or 6 weeks may have clogged up the EVAP system to the point where it is preventing the engine from running. He also suggests that I check the condition of the EVAP system hoses in that area to see if they have cracked or disintegrated. He had an almost identical issue with a Ford years ago in which a disintegrated EVAP hose kept the engine from running....

We both wondered if something like that could confuse the ECU to the point where it would throw P0603 and P0607 as spurious codes. Anyone care to speculate?

 

Update:

I tried the "Ignition key turned to Position II for 5 seconds" procedure three successive times without attempting to start the engine. I then waited about 20 seconds, started the engine, but it again fired up and cut off in less than two seconds. During this time I noticed the messages "DSC System Fault" and "Cruise Not Available" on the dashboard display....

 

Update:

A hard reset (removing both battery cables and touching them together for 30 seconds) fixed the not-starting issue and I was able to clear both the P0603 and P0607 code with my scanner. Now the car is back to just the P0447 EVAP valve issue that Dale (crbass) and I can hopefully get together and diagnose in a couple of weeks....

Just to ensure roadworthiness I took the car for another 10-mile exercise run after starting it up. It performed normally....

Chalk this little episode up to the ever-present electrical gremlins that tend to live in most Jaguars. They can indeed be pesky (and sometimes expensive)....

Thanks to all for the quick and effective assistance. I would not be willing to keep this now-rarely-driven XK8 without this forum always having my back....

 

10 miles is not very far. If you've a ctek-type thing maybe just do 50 miles once in a while.

If no ctek, 10 miles probably isn't far enough - I'd do at least 20.

Hopefully the P060x were fakes!

 

I hear you. I will try to put a few more miles on the car later this week. Too many other more important things I need to do now so the XK8 will have to wait its turn....

 

Update:

Took the 2006 XK8 for a 25-mile backroads jaunt yesterday afternoon. It got a chance to stretch its legs and I know it appreciated that....

I checked my records and confirmed that I did the 120,000-mile service back on May 25th. Before driving it yesterday, I noted that the car had done just 112 miles since then. I obviously need to drive this thing more. It is my wife's toy, yet she has not set foot in it in months....

 

Hey folks, this is just an FYI for any Jag owner who suddenly has intermittent starting problems and has an after market component attached directly to the battery terminals. In my case it was an Sirius radio already connected when I bought my XKR. Never used it but all of a sudden starter wouldn’t turn over, intermittently. Had alternator and battery checked.. both fine. Did my my DIY diagnostics by checking terminal connections and moving wires around, and it would often then start. Using the process of elimination, I disconnected Sirius leads and have had no problems since. Just a thought that anything directly connected to your battery leads that’s not factory is capable of creating all kinds of grief...