I have a 2012 XJL Supercharged that ended up requiring a new engine. Yes, it was the dreaded tensioner failure that did it in. The guide on the passenger side split into three pieces and dropped down behind the front cover. Moving on. New engine (0 miles) installed and now we are chasing code gremlins. The car runs and drives beautifully, but once parked and shut down, it will throw the following codes on the next restart: P0102-00, P010C-00, P0117-16, P0010-13 and P0020-13. I am aware of what each code means, but unsure why they are showing up.

The MAF is not new, but worked perfectly before and the K&N filters are clean. No air leaks that I can find. The temp sensor is new and was part of the newly replaced engine coolant pipe assembly. The OCV on both camshafts are new with the new engine. Battery has been replaced with a new one since the old one didn't like sitting as long as it did. The new battery and the prior battery are not AGM (Absorbent Glass Mat). Electrical connections to the sensors have been checked repeatedly.

After turning the car off and attempting to restart, the codes appear and the car is in limp mode. They do not reappear once cleared and while the car is running. If allowed to sit overnight, the same codes appear and the car won't start at all. The car starts right up if the codes are cleared. It then idles beautifully and runs like a champ... until it is shut off, then this starts all over again. Hoping to avoid a trip to the dealer for a re-flash...and unsure if that will do anything anyway. Anyone encountered this sort of demonic possession before? Thanks!

 

Portfoliolio, from the sounds of things, it is almost like you have a portion of a wiring harness that is really near to grounding and only when the engine is turned off, does the cable move far enough to cause the ground. I would have to venture that it would be down near the exhaust pipes as that is the only way that I could see getting multiple wires damaged without having one be hard grounded. I would follow the cam shaft sensor wiring and see where it runs along side the engine until it hits the firewall. I think once you make the turn to start heading towards the firewall, you will find your issue.

 

Still waiting for the mechanic to return from his Turkeyday break. Inspection of the wiring is pending. I'll post as soon as I know anything. Thanks!

 

Make sure there's at least 12.6 volts available from the battery. Use a voltmeter to read the voltage across the terminals with the ignition in the OFF position.

 

Still chasing gremlins. Can't see any issues with the harness after a week on hunting and inspection. Battery is new and meets voltage requirements. Same drama. Different day.