Hey guys! My 2012 Jaguar xf supercharged will no longer start. My issues started after I did a spirited pull and got a restricted warning light. I immediately pulled over and shut the car off. After restarting the car I had no error messages and it Felt completely normal. I tried to make it act up again and I noticed at 5000rpm a slight misfire or hiccup in the powerband and the restricted warning light would come back only under extremely heavy throttle at exactly 5k. I parked the car for the night and tried to start it in the morning. It was a very rough cold start but it reluctantly started. After running the car for a few minutes, I shut the car off and restarted it. The car showed no sign of struggle and started perfectly multiple times after. It drove completely normal but did continue to have a slight hiccup at 5000rpm under heavy throttle only. Finally I was driving to the store and the car had suddenly felt like it ran out of gas but had a full tank. The engine stalled for a brief moment but came back to life. I then parked the car at the store and went shopping. When I came back out, I tried to fire up the car but it refused to start. It sounded as if the fuel pump was faulty. I had it towed to a local Indy and he tested the fuel system. He said the car was showing no symptoms of fuel issues. He then performed a “global reset” and the car started with no issues few hours later. He recommended I change my battery which I did. I picked the car up and it continued to have the same initial rough cold start and hiccup at 5k rpm. I was then driving on the highway and the car shut off going 80mph. I safely steered the car to the shoulder and had it towed to my house. As soon as it arrived, the car started perfectly on the back of the flat bed with no issue. I then left the car in my garage for a week or 2 and drove another vehicle. I took it for a spin around the block and then the car stalled out for the final time and will no longer start. At this point, I’m thinking it has to do with the crankshaft position sensor or it’s a faulty fuel pump. There are no codes or CEL. Any guidance would greatly be appreciated! Sorry for the long read!

 

I find it really hard to believe there isn't a single code or CEL if it won't start - all the things required for the engine to run are monitored fairly intensely by the ECU so the idea you wouldn't see a code would suggest either a problem with the code reader or worst case the ECU maybe. What code reader are you using?

Is the engine turning over fast enough when you try to start it? How's the battery?

 

The car was towed to a local Jaguar Indy who ran the codes but stated nothing was stored. He performed a global reset and the car started again a few hours later. He said he would have to run further diagnostics to figure out the true issue. I replaced the battery at that time and still had the same issues. The only warning light I’m getting is when the restricted performance light comes on and the car falls into limp mode. Turning the car off and on resets the performance light. No Check engine light or codes according to the Jaguar Indy or the dash. I didn’t not run the codes myself because I do not have a proper scan tool.

 

Hi,
My XF was behaving in a similar way. My solution was to replace the throttle body. All the problems went away. My car also has both egr valves bypassed. It now runs superbly! Another problem, at least in the UK, is the fuel quality. Diesel fuel supplied at supermarkets is allowed to have a considerable amount of biofuel added to it. This is bad for a performance engine. Hope this helps