Alternator problems ?

Jeep1969

Member
Joined
Jul 5, 2019
Messages
16
Reaction score
3
Location
Louisiana
Vehicle(s)
JLUR
Hello forums members,

when I press on the gas pedal the voltage goes down to 13 volts, and when I let go of the gas pastel and coast , I can see the voltage meter jump up to 13.8 then back down to 13 when I’m at a complete stop. Last week I changed out The main battery and AUX battery. It was 14.4 volts for like two days.

Check engine light is now on, went to autozone and they said I have a code p0456 emission leak.

Alternator test came back fail. But could it be a bad relay or a voltage controller?

Jeep appointment is 3 weeks out just to do a diagnostic, I need the Jeep as my wife’s daily and I can’t be changing out batteries until the appointment date. Jeep dealer said they don’t have any rentals loner jeeps available, I would have contact a car rental company.





Advertisement

 

DaltonGang

Well-Known Member
Joined
Sep 29, 2018
Messages
1,264
Reaction score
1,471
Location
Houston, Tx
Vehicle(s)
2018 Wrangler JLU Sport S, Rubicon Suspension, Tires, and Rims. Firecracker Red
Mine was wacky to, and causing ESS issues. The IBS Sensor was replaced, and fixed the issues. I thought it was a battery problem, as did many others here. But, these Jeeps are sooooo electronically complicated, nothing is as it appears.
 

Heimkehr

Well-Known Member
First Name
James
Joined
Sep 3, 2020
Messages
1,127
Reaction score
2,002
Location
Pennsylvania
Vehicle(s)
2021 Jeep Wrangler Unencumbered
Last year, I had a similar problem on one of my motorcycles. The culprit was a failing shunt-style regulator/rectifier. I replaced that OEM fitment with an upgraded MOSFET R/R, which solved the improper charging.

The foregoing can't be directly crosswalked to your JLUR, but with my own experience in mind, I'd ask the dealer to first check the voltage controller and the alternator, in that order. Alternator failures when only a few years old are anomalous but not unknown, so it is a possibility here.

I wouldn't be surprised if the battery required replacement, too, recalling the old wisdom that many electrical problems can be fixed by replacing the battery. Hopefully the dealer gets this solved quickly for you.
 

WranglerMan

Well-Known Member
First Name
Will
Joined
May 8, 2018
Messages
3,158
Reaction score
2,262
Location
Katy Texas
Vehicle(s)
2018 Wrangler JLU Sahara
Occupation
Gas Pipeliner
Vehicle Showcase
1
The floating voltage you are seeing is normal for a vehicle that is equipped with smart charging, during times of decelerating or braking the alternator will be put under load and during acceleration for steady speed the voltage will settle down to a likely lower number.

It does this to reduce the load on the system to supposedly give you slightly better HP and better mileage, the days of seeing 14+ volts all the time are long gone but other things like a failing IBS or batteries being under charged can be an issue to.
 

four low

Well-Known Member
Joined
Feb 1, 2017
Messages
2,206
Reaction score
2,404
Location
central New York
Vehicle(s)
2018 JL
Since you already replaced both batteries, the charging voltage may be normal. The 14 v was for failing batteries.
What does the voltmeter read when you have everything on, lights, wipers, AC, at idle. 13v and above should be good.
The IBS ( Intelligent Battery Sensor) determines how much charge the battery receives, and may be at fault if low voltage shown on voltmeter.
If you search " IBS " you will see a post back in March, regarding the relearning process for the IBS when it is disconnected, as it would be when your batteries were replaced
 
Last edited:
OP

Jeep1969

Member
Joined
Jul 5, 2019
Messages
16
Reaction score
3
Location
Louisiana
Vehicle(s)
JLUR
  • Thread starter
  • Thread Starter
  • #6
Just to update, dealer held the Jeep for a week, during drop off I told the service manager all my issues
1. Check alternator, IBS Bc I just installed two new batteries, main and small aux battery myself.
2. Steering, I have to constantly micromanage the steering left and right at all speeds to track the Jeep straight.
3. Blast of hot air blowing into the cabin out of no where, usually on road trips it happens
4. Back up camera guide lines no longer shows up.
5. check engine light code P0456
Constantly filling the gas up and making sure the cap is tight.

I had to call every two days to get an update and for them to actually do anything. Monday drop off, nothing, Wednesday I call and ask for an update. They said they are in the process of changing out both batteries. I told them those battery are new from autozone. They said ok good, but we will give u back your autozone batteries. I asked them to check the other items on the list. They said ok.
Friday morning I called and ask for an update. They said they changed the batteries, how about other items on the list? “We weren’t able to produce the other problems”. They said they can take another test drive next week for the steering but would need to leave the Jeep for another week or so.
I came and got my Jeep on Saturday. They don’t provide a loner Jeep and suggested I go to a car rental place, and my wife needs the jeep go to work and pick up the kids From school. So over all nothing was done in my eyes. I still have all the same problem, I ask if my alternator and IBS still working ? They said it should be ok now with the new batteries. Sent me on my way. @JeepCares.
 

WranglerMan

Well-Known Member
First Name
Will
Joined
May 8, 2018
Messages
3,158
Reaction score
2,262
Location
Katy Texas
Vehicle(s)
2018 Wrangler JLU Sahara
Occupation
Gas Pipeliner
Vehicle Showcase
1
@Jeep1969 in regard to what you are seeing on the battery voltage as I said it’s normal

As you can see as I accelerate the voltage drops and when decelerating it goes up and this is by design, if your voltage sits at 14+ all the time then you possibly have an issue and that can range anywhere from the Jeep sitting parked a lot to a issue with the batteries or IBS


In regard to the hot air blowing randomly thats also by design, not sure there is a TBS that addresses this or bot but I have had my recirc controller disconnect for over two years
 
OP

Jeep1969

Member
Joined
Jul 5, 2019
Messages
16
Reaction score
3
Location
Louisiana
Vehicle(s)
JLUR
  • Thread starter
  • Thread Starter
  • #8
I even printed out all the issues with TSB and the dealer said if we can’t reproduce the problem we will not update the AC program.
 

Advertisement




Winjet
 



Advertisement
Top