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I have the V6 engine. When i hit speeds over ~50 mph, the check engine light turns on, and the 4WD temporarily unavailable alert comes on. When it does, my car does not accelerate and barely keeps the momentum. I also feel the steering wheel is heavier and hard to turn.
 

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I also still occasionally get "4x4 temporarily unavailable" and a red circular light on the dash.

For me though, this is always related to turning on the headlights, or flashing someone my high beams.

This was happening frequently before I changed my battery about a year ago, but has continued happening every once in a while since then.

Most often it happens under 2 scenarios:

-I start the car and immediately turn the headlights on.... and ding!!!!
-I have been driving on the freeway for an extended time, and I either need to flash someone, or the sun sets, and I need to turn on my headlights.

The dash re-sets simultaneously , and the spedometer and tachometer do their little dance going all the way up, all the way down, and then resuming operation, and the Cherokee's EVIC and radio reboot.
The car enters some sort of safe mode where acceleration is reduced, and the power steering assist is noticeably decreased (the steering feels much stiffer, which incidentally, I actually prefer).

This seems to also happen more often when it's cold outside.

I do have aftermarket 35W HIDs installed with PWM "smart" modules.

I have taken it to the dealership multiple times, they did a BCM update to no avail, and claim that it is most likely related to my aftermarket headlights, and refuse further diagnostics.

Every time this happens, I have to pull over, turn the ignition off, take the key out of the ignition, lock the car, and wait 3-5 minutes for all of the computers to totally shut down, and only then can I start the car without the warning still being there.
Hmmmm. I've heard of "headlight bulb out" errors when turning On aftermarket HIDs, but 4WD temporarily unavailable ? Steering assist (electric) going offline, because of HIDs ? This is a first for me. I've had 4WD temp unavailable and steering assist disabled on cold starts in winter, but that was when my battery was nearing death.

Could this be linked to some kind of interference from the HID ballasts in your case ?? My Xenon Depot 35W HIDs cause no such problems, ever, except the rare healight bulb out error when I turned them On immediately after a cold start.
 
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Hmmmm. I've heard of "headlight bulb out" errors when turning On aftermarket HIDs, but 4WD temporarily unavailable ? Steering assist (electric) going offline, because of HIDs ? This is a first for me. I've had 4WD temp unavailable and steering assist disabled on cold starts in winter, but that was when my battery was nearing death.

Could this be linked to some kind of interference from the HID ballasts in your case ?? My Xenon Depot 35W HIDs cause no such problems, ever, except the rare healight bulb out error when I turned them On immediately after a cold start.
My gut feeling is that turning on the headlights produces some sort of voltage drop due to the surge current the ballasts need for a moment at first, which triggers a safety condition somewhere in the computer system (either ECU, BCM, PTU, or RDM) which shuts off 4x4 so that it doesn't destroy itself if various components aren't able to synchronize their functions correctly due to insufficient voltage/current.
But who knows???
 

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My gut feeling is that turning on the headlights produces some sort of voltage drop due to the surge current the ballasts need for a moment at first, which triggers a safety condition somewhere in the computer system (either ECU, BCM, PTU, or RDM) which shuts off 4x4 so that it doesn't destroy itself if various components aren't able to synchronize their functions correctly due to insufficient voltage/current.
But who knows???
That's a possibility, for sure. We just haven't seen it happen before, not this severe. Something to keep an eye on and, hopefully, answers will come.
 

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That's a possibility, for sure. We just haven't seen it happen before, not this severe. Something to keep an eye on and, hopefully, answers will come.
So, it happened again last Friday when my wife and I were heading up to our cabin.
It reminded me of another effect that I also observe whenever this happens:
The windwhield wipers "twitch". They move about an inch (and stay there) at the same exact moment the dashboard, EVIC, and radio "reboot" immediately before I get the 4x4 temporarily unavailable warning.

Maybe instead of a voltage drop, there is a surge, or a short somewhere in the system???

As a workaround, for the time being, I am turning my headlights on prior to starting the jeep if it's within a couple hours of sunset just in case I might need my headlights before I reach my destination.
 

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I have the V6 engine. When i hit speeds over ~50 mph, the check engine light turns on, and the 4WD temporarily unavailable alert comes on. When it does, my car does not accelerate and barely keeps the momentum. I also feel the steering wheel is heavier and hard to turn.
So, it happened again last Friday when my wife and I were heading up to our cabin.
It reminded me of another effect that I also observe whenever this happens:
The windwhield wipers "twitch". They move about an inch (and stay there) at the same exact moment the dashboard, EVIC, and radio "reboot" immediately before I get the 4x4 temporarily unavailable warning.

Maybe instead of a voltage drop, there is a surge, or a short somewhere in the system???

As a workaround, for the time being, I am turning my headlights on prior to starting the jeep if it's within a couple hours of sunset just in case I might need my headlights before I reach my destination.
Hey there @brimac09 and @sport_4x4
We are sorry to hear that you are experiencing these concerns with your vehicles. We recommend that you get a first or second opinion from your dealer in order to be properly diagnosed. Feel free to send our team a private message for additional support during your dealer visit.

Kathryn
JeepCares
 

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This EXACT thing happened to me. The 4WD temporarily unavailable light came on and then my acceleration went down the drain. I pulled over, turned my car off, sat, turned it back on and it was running fine after. However, this same issue seems to come up when I am at highway speeds for extended periods of time. I want to take into the dealer before I go on a road trip but wanted to check and see what your experience was after bringing it in.

thanks.
I see that the Jeep team started to engage with you... which was not the case for me. Not sure what their criteria are...

Anyway, I have been procrastinating and never brought my Cherokee to the dealership :( Fortunately, so far I didn't had any issues after that incident. Fortunately, I didn't experience the same issue - but to be honest, I have been driving way more carefully in corners as I lost the trust in my vehicle.
 

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This EXACT thing happened to me. The 4WD temporarily unavailable light came on and then my acceleration went down the drain. I pulled over, turned my car off, sat, turned it back on and it was running fine after. However, this same issue seems to come up when I am at highway speeds for extended periods of time. I want to take into the dealer before I go on a road trip but wanted to check and see what your experience was after bringing it in.

thanks.
What did they say the issue was for you? I’m having this exact issue happening to me right now. Had it in the dealership and they said it was the abs module. They changed that but I’m still having the same problem!! I’m currently sitting on the side of the highway because I can’t go faster tha 45mph!
 
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