Hey so recently bought a Jaguar xj8 from a guy of Facebook and according to him the car had been sitting in his garage all throughout winter. The car only has 90,000 miles on it and is in really good shape, the only issue is that the car wont crank due to this failsafe engine mode. He told us that he took it to a Jag mechanic and that he was told to fix the fuel pump. I replaced the battery and the fuel pump and nothing has seemed to change. I also tried reading the code on the OBD2 reader and it kept on saying error. I also went to O Rylie's and used one of there readers and it wouldn't connect. I'm starting to run out of ideas on what to do does anyone have any advice they can give me. I also checked all the fuses and they seem fine.

 

It could help us better diagnose your issue with just a
bit more information. Do you have fuel pressure at the
shrader valve? Are the plugs getting spark? Do you have
adequate compression? Have you tried starting fluid? How
old is the fuel in the tank?

 

I would love to check those things, but unfortunately, the Jag is in failsafe engine mode so the computer won't allow it to crank at all. These are errors that show up on the dash when I turn on the power:

1. ASC NOT AVAILABLE
2. TRANSMISSION FAULT
3. FAILSAFE ENGINE MODE
4. INCORRECT PART FITTED

Like I mentioned the OBD2 is not connecting to give us any more information. Thanks for any help or insight you can provide.

 

When use say "won't crack" do you mean won't turn over or won't fire? I think "incorrect part fitted" can be a problem with a module. Either bad module, bad connection at module or blown fuse to module. I'm no expert on the CAN but the CAN wiring goes in and out of each module in a big loop. Thus, a failure at one module can cause cascading errors. I'm sure one of the retired Jag mechanics will jump in.

 

Yes it won't turn over or fire. When I try to crank it I get no sound.

 

Engine failsafe mode should not keep it from cranking when you turn the key...at least it has never happened in mine when I have that code flashing on the display...the engine has always cranked and started, but it runs poorly because its in a low power preset mode that will get you moving and is intended to allow you to get your car off the road and you away from traffic, etc.

Incorrect part fitted and the fact that 2 separate code readers refused to connect to the car's OBDII port properly suggest the prior owner probably had something wrong and they tried to fix it by replacing something and it was possibly the wrong year...like they fitted a 98 ABS module into a 2002 car for example. The inability to connect to the car's computer I think is the first thing that needs to be resolved...if you can't connect to it, its probably not working right and if tis not working right, it'll never run right. Check all over for loose or possibly disconnected (or even dirty/corroded) computer connectors. Do this with the battery disconnected so there is no chance of accidentally sparking and created a new problem.

The lack of cranking at all make me wonder about the battery voltage. Even though you replaced the battery, it might be dead if there's some kind of draw in the car, especially if the prior owner was messing around with computer modules and such. Can you check the voltage and see whats left in the battery? If you have a charger you can't be hurt by putting it on there.

 

Move the ignition relay around if no crank it's usually the ignition relay also check the fuse box behind the driver seat

 

I'm assuming that your obd rreader could contact to the ecm fine but it does not because ecm do not respond.
If ecm do not exist in can bus or can bus is broken. Engine wil not turn over since ecm does the start accepting and allowing.
Since dash is telling about wrong module installed, is ecm replaced just by bolting it in? What has the Jag repair guy done?