Hi,
As the technical liaison for various models in our club, I have for the first time had a case from an XF owner;
Out of the blue last weekend, cruising in 50km/h, the engine started misfiring and died within seconds. Message on the screen was «Gearbox failure», «DSC not available» and «Battery fault» (the latter only flashed up on the screen for and disappeared).
After this, the car wouldn’t fire up, but after being left alone for 5 minutes, it fired up as normal. Went through the gears with nothing untoward to be heard, but after a few minutes idling, the same happens again. Engine warning light is lit plus the same messages as above constantly displayed.
He’s looked into the battery and made sure that is good and fully charged. BTW; does this car have an extra auxiliary battery, like some Mercedes of the same vintage have?
Also checked all the relevant fuses which were cleaned to the metal. Started up again and the car ran for about 15 minutes, then died.
Did a diagnostic test at a workshop, resulting in messages relating to the fuel pump and CPS (Cam position sensor), which I myself lean towards as a plausible explanation.
Not sure if this is much help. The cars do not have an auxiliary battery. And from what you describe, I’m definitely leaning towards some type of electrical fault. I can’t imagine a fuse would do something like that. Someone who is good with a scan tool may need to take a closer look at things because you certainly don’t want to start throwing parts at it.
this is the battery or the voltage regulator.
The DSC shuts down in all and any cars when voltage is wrong. And the other two issues, happening at the same time, correlate.
Don’t go about it with fuses or wiring faults, it is a modern car. Maybe something has been stored and he can read the codes, if not, I‘d wait for the failure to reoccur. I doubt the CPS or pump have much to do with it, even though, ignoring the battery fault warning for a second, the CPS is slightly plausible. However, in that case the check engine light should turn on and the engine go in to limp mode I‘d say. No, I‘d vote for overvoltage, or undervoltage. A good battery doesn’t always mean a lot, I had batteries with good voltage fail, and our Mercedes has had overvoltage issues last winter; I delayed fixing it until it fixed itself. It showed DSC, alternator and battery failure, xenon lights shut off and the interior light turned almost blueish for a second, scary. It shot up to 18V for a few long moments that one time I could replicate it.
I‘d be interested in what it was in the end, good luck.