1999 XJ8 Stabilization warning and low power mode activates

Not finding an XJ8 category I’ll post here. Recently purchased a 1999 XJ8 with 3.0 V8. Mileage 58,514 actual. Owner informed stabilization warning light alerts at times. Upon tagging and driving car, can hear thump in rear over rough road and then afterward when slowing for a light or stop sign car goes into low power mode. No rough idling nor engine dies
while driving at speed. Seen various explanations from low battery voltage, which checks at 13.5 charging/running, to throttle body build up. Ride height remains same. Can the ride system throw into low power mode if faulty?


Hi Ronnie, welcome to the forums.
I have moved your post to the X300 group as that covers your model.
Check the battery after sitting overnight and then if its still registers above 12.7v then it ‘might’ be ok but I would also do a draw down test at an Auto electrician.

Thanks. I’ve already checked battery a few days apart and it’s around 12.5 before starting, but I’ve seen battery issues before on my Mopars concerning sensors. Battery is 6 years old by sticker info and I think I’ll just go ahead and replace it to be sure it’s not the problem. And I understand the throttle body has to have enough voltage to open properly and not be sluggish. I’m just starting on it, need to purchase a manual and keep studying up. Thanks again.

Replaced the battery yesterday. Have driven it over 50 miles since and no trips on sensors and no low power mode activation. Previous battery was vented type and hose not being attached showed where acid had traced out of port and left white residue around base of the battery. Battery would start and stay charged but when lights, radio, and everything else pulled voltage the system was going low enough to trip sensors. My opinion, but anyway it’s rolling and so far so good issues stopped.