Hey guys
just got a XJ L Supercharged. It’s a great car but having a really bad problem.
anytime I step on the gas electronics shut off.
if I’m driving slow under 2k RPM car drives with no problems at all. As soon as I start pushing power the car goes crazy.
- Headunit dies
- All climate stops blowing
- Eco start/Stop unavailable
- TPMS unavailable
- Blindspot unavailable
- Car won’t recognize my key if I shut car off during this problem

after driving slow for a few minutes everything clears up and car drives normal again.
any ideas??

 

I tested the battery and alternator everything checked out. Car has original battery in it from 2014 I’m thinking to buy a new battery regardless. Any thoughts?

 

dlukomskiy, what you are describing sounds like a bad ground issue. What I would tell you to try doing is running a wire from the body of the car to the engine. Make sure that it is a decent gauge wire (say 12 guage). You may want to put lugs on the ends to make attaching it easier. But, find a bolt on the firewall that is easy to get to and then a bolt on the engine itself. Connect the two with the wire. If your problem goes away, then this confirms that the ground wires in your car need some attention.

 

No help here, I would have guessed alternator or battery. Good luck.

 

If you just got it I would take it back and get it fixed.

This could be a simple or complex problem we just don't know.
.
.
.

 

Just tried this
and problem still exists. Any other ideas?

 

dlukomskiy, at this point, you are going to need to get out a multimeter. I think your next step is to measure the 12 VDC inside the cabinet area. You are going to want to measure it at 2 different RPMs. One time at say idle and then again up at say 4000 RPM (when the problem is in effect). If the voltages are the same, then we are looking at a computer issue, not a voltage issue. If you see the one voltage drop to under 12.6 VDC, then we have a wiring issue. Lets start here and then see what we have at that point. A simple way to do this is if you look at some cell phone chargers, they have a volt meter built into them. I have this on my car and it gives me 2 permanent USB ports to charge stuff from and tells me the voltage the car is running at. Cost me like $12 through E-bay and the one I got fit in place of the power port on the back side of the center console. Took all of about 30 minutes to install. Otherwise, you will need to find a power source to measure voltage at. This is where I would say to look at the power port in the center console. Fairly easy to access and won't have other things on the circuit cauasing it to do funny things to you.