Stop/Start Not Ready Battery Protection Mode Jeep [Solved]

Error messages can be perplexing to you only if you have no clue what’s going on. That’s why we will review the common Jeep error message, “Stop/Start Not Ready Battery Protection Mode.”

So what does the “Stop/Start Not Ready Battery Protection Mode Jeep error message indicate?

A faulty main, auxiliary, or both batteries are the root cause of this problem. Sometimes, high cabin temperature can also trigger this message. Other than that, a dysfunctional alternator, worn serpentine belt, malfunctioning IBS sensor, or rarely a PCM issue can cause this. Also, an intermittent circuit caused by wiring problems or a blown fuse can also be an issue.

Now, let’s talk about what you should do to reset this error message.

The Meaning of Stop/Start Not Ready Battery Protection Mode Jeep

jeep stop start not ready battery protection mode
Source: jlwranglerforums

To understand what’s happening with your car and why the error message suddenly showed up, you need to be clear about what it means. Before we start providing solutions, let’s explain what it means.

What Is Battery Protection Mode Jeep?

Battery Protection Mode is a feature that you can find in some Jeep vehicles. This prevents your battery from being completely drained, thus extending its life.

Here’s how it works: When your battery is too low, the Battery Protection Mode kicks in. The battery is automatically disconnected from the vehicle’s electrical system. Only a little bit of power is used to maintain the vehicle’s settings and memory. 

By doing this, Battery Protection Mode helps you avoid draining your battery completely, which can be really bad for it and shorten its lifespan. Also, if you tend to store your Jeep for long periods, this feature can be really useful.

What Does Stop/Start Not Ready Mean?

“Stop/Start” is an engine start-stop system that you can find in some Jeep models. Essentially, it’s designed to automatically turn off the engine when the vehicle comes to a stop. Like at a traffic light, and then restart it when you take your foot off the brake pedal. This helps to save fuel and reduce emissions by avoiding unnecessary idling.

However, if you see the message “Stop/Start Not Ready” on your Jeep’s display, it means that the engine start-stop system is currently unavailable to use. This is due to a low charge in the auxiliary battery, which powers the vehicle’s electrical systems.  

When the auxiliary battery has a low charge, it can’t provide enough power to operate the ESS system properly. As a result, the system is disabled until the battery is recharged to an appropriate level.

Why Does Stop/Start Not Ready Battery Protection Mode Trigger?

The error message “Stop/Start Not Ready Battery Protection Mode” usually triggers because of a low auxiliary battery charge. This doesn’t mean that there is a malfunction in your Jeep. 
In the best-case scenario, this can occur if your car has not been driven for a long time. Because of that, the battery did not get a chance to charge itself. Once you start driving the vehicle, the battery will charge itself. When that happens, you will notice another message, Stop/Start Not Ready Battery Charging.”

Stop Start Not Ready Battery Protection Mode Trigger
Source: jlwranglerforums

Also, if your Jeep’s battery temperature is not within the specified range (-22°F to 131°F), this error message may also appear.

But if there is a malfunction in the battery or the charging system, the error message will not go away by itself. In that case, you will have to take your Jeep to a mechanic or diagnose the problem itself.

Here are the possible defects that may cause this error message to not go away.

A Defective or Dead BatteryBattery light on, dimmed lights, electrical components not functioning properly.Replace the battery if it’s defective. Apply the baking soda-water mixture to clean the corrosion.
A Defective AlternatorBattery light on, malfunctioning electrical accessories, burning smell,growling or whining noise.Replace the alternator.
A Worn Serpentine BeltSquealing noise, loss of power to the AC or the power steering, engine overheating, battery not chargingReplace the serpentine belt
Blown FuseDimmed lights, electrical components not functioning properly, loss of powerReplace the fuse
Wiring ProblemsThe check engine light or the battery light is on, flickering lights,electrical components not working properlyReplace the wiring
IBS MalfunctionBattery light on, electrical components not working properlyReplace the IBS
PCM MalfunctionCheck engine light, vehicle not starting, engine misfiring or stalling, multiple DTC codes etc.Consult a mechanic

Reason One: Defective Auxiliary Battery

As your Jeep has ESS, it has an auxiliary battery in addition to the main battery. This auxiliary battery powers the ESS, entertainment system, etc.

A bad or dead auxiliary battery can also activate the stop safely vehicle will shut off soon error message. That’s because then it starts to drain the main battery.


  • Battery light on
  • Flickering lights
  • Electrical components malfunctioning.


To know for sure if your auxiliary battery is defective, you can do the following-

  • Locate the battery: The location of the auxiliary will vary based on your make and model. Refer to your owner’s manual for finding the exact location of the auxiliary battery. In some models, the battery is located under the passenger seat.
  • Inspect the battery: Once you have located the battery, examine it. Look for cracks or leaks. If the battery stinks it also is a sign of a defect. Remember to check the terminals for corrosion too. If you do find anything like that, the battery may have a defect.
  • Perform a voltage test: You will need to whip out your multimeter for this. Set the multimeter to measure DC voltage and make sure you turn off the engine and all the electrical components. 

Connect the multimeter probes to the battery terminals. The multimeter should give you a reading by now. A fully charged battery should have a voltage of 12.6 volts. If it’s less than that, the battery is not charging well. This indicates a problem with the battery or the charging system.

  • Perform a load test: If the battery voltage is 12.6 you can do a load test to check its health. For this, you will need to get a load tester. Turn off the engine and all the electrical components. Then connect the load tester to the battery terminals.

Now, turn on the load tester to send a load to the battery and see if the battery can hold the load for about 10-15 seconds. If the voltage drops below 9 volts, you can confirm that your battery is defective.


If your battery is defective, you will have to replace it. Here is a video to show you the complete process of replacing the auxiliary battery on a Jeep.

 Auxiliary batteries typically cost between $200 and $300. On top of that, you may need to pay an extra $50 to $100 in labor costs.

If the terminals are corroded, you can just clean them with a mixture of baking soda and water. Apply baking soda all over the corrosion. Then add a few drops of water to make a paste of baking soda. After half an hour, clean the battery with water after removing the paste.

Reason Two: Defective Alternator

Occasionally, the low battery voltage can also be an indication of a problem with the charging system. Your first step should be to examine the alternator, which is the main component of the charging system.


  • Battery light on
  • Malfunctioning electrical accessories
  • Burning smell
  • Growling or whining noise


The alternator is responsible for charging the batteries in your Jeep. So, if the battery is not charging, the alternator is not doing its job.

Begin by measuring the battery’s voltage with the car turned off. The battery should register a voltage of 12.6 volts when the vehicle is not in use. Leave the multimeter connected and start the car. The voltage should then increase and remain within the range of 14.2 to 14.7 volts.

If the voltage exceeds or falls short of the specified range when the car is on, this indicates that the alternator is not charging the battery correctly. In this scenario, it suggests that the alternator is defective.


In the event of a faulty alternator, it is necessary to replace it with a new one. Depending on the vehicle’s model, the cost of a new alternator typically ranges from 100 to 300 dollars. If you plan to replace the serpentine belt as well, add an additional 20 to 50 dollars. The labor cost for the replacement should amount to approximately 50 to 100 dollars.

Alternatively, if you prefer to undertake the alternator replacement yourself, you can follow the steps outlined in this instructional video.

Make sure you follow the steps in the video exactly. Improper installation can cause the alternator to burn out quickly

Reason Three: Worn Out Serpentine Belt

The alternator is driven by the serpentine belt. Therefore, the issue may be with the serpentine belt.

Worn Out Serpentine Belt
Source: Humble Mechanic

Worn, damaged, or loosely-fitted serpentine belts can impede the alternator’s rotation, leading to electrical problems.


  • Squealing noise
  • Loss of power to the AC or the power steering
  • Engine overheating
  • Battery not charging


To determine whether the alternator is worn out or damaged, it is necessary to perform a visual inspection. To begin, locate the serpentine belt, which is typically situated on the engine’s front and connected to the crank.

After finding the belt, examine it for any signs of cracking. The presence of cracks on the belt indicates that it is worn out.


If the serpentine belt is worn out, a replacement must be obtained and installed. A mechanic can complete this task, in which case you should expect to pay around 50 to 150 dollars in labor costs in addition to the approximate cost of the belt.

However, if you prefer to undertake the replacement yourself, you can follow the step-by-step instructions provided in this video tutorial.

Reason Four: Defective Intelligent Battery Sensor

The intelligent battery sensor, or IBS for short, is responsible for monitoring the battery’s condition and updating the ECM. A malfunction of the IBS can trigger this error message. 


  • Illumination of the battery light
  • Improper functionality of electrical components


To diagnose an issue with the IBS, a DTC code reader is required. Start the vehicle without turning on the engine, then plug the OBD code reader into its designated port located under the dashboard. The DTC code reader will display error codes associated with the IBS, such as U113E.


If the IBS is determined to be faulty, it must be replaced. To do this yourself, follow these steps:

  • Turn off the vehicle and allow the engine to cool.
  • Locate the IBS, which is typically mounted on the battery itself.
  • Loosen the nuts securing the sensor to the battery.
  • Disconnect the sensor’s wiring harness.
  • Remove the old IBS and replace it with a new one.

Reason Five: Damaged or Corroded Wiring

If the charging system components are functioning properly but you are still experiencing issues, it’s possible that there is an issue with the connection or wiring. Intermittent circuits can be caused by loose connections, damaged wiring, or corroded or burned wires.

If your battery cannot provide required voltage due to damaged or corroded wires, the error message will show up. 


  • Check engine light or battery light is on
  • Flickering lights
  • Electrical components not working properly


To identify any wiring issues, you should inspect the connections and wiring between the battery, alternator, IBS, and ECM. Check for loose connections by gently wiggling the wiring. Look for damaged insulation, corrosion, frayed wires, or wires that appear burned or melted.


If you identify any loose wiring, reconnect it. For damaged wires, you will need to replace them with new ones. It’s important to address any wiring issues promptly to avoid more significant electrical problems down the line.

Reason Six: Blown Fuses

Even if the battery, alternator, or serpentine belt is in good condition, blown fuses can prevent them from working properly. Electrical fuses are a safety measure that limits the current flowing through circuits. When a fuse blows, it stops the electrical connection and prevents current from flowing.


  • Dimmed lights
  • Malfunctioning electrical components
  • Loss of power.


To diagnose a blown fuse related to the battery or alternator, locate the fuse box, which is typically located in the engine compartment or under the dashboard. Refer to the fuse box cover or owner’s manual to find the specific fuse related to the alternator or battery. 

Use a fuse puller to remove the fuse and inspect it for a broken or burned metal filament. If it looks okay, use a multimeter to test for continuity by touching the probes to each end of the fuse. If the multimeter reads zero, the fuse is good. If it reads “infinity,” the fuse is blown.


If the fuse is blown, replace it with a new one with the same amperage rating.

Reason Seven: Defective PCM

While it is uncommon, a malfunctioning PCM can also be the cause of this warning message. However, an issue with the PCM can result in a plethora of error codes and malfunctions, as it is essentially the car’s brain.


If you suspect that your car has a PCM problem, it is recommended to take it to a skilled mechanic to diagnose the issue. The cost of diagnosing a PCM problem may range from $150 to $200.

If the diagnosis indicates a faulty PCM, be prepared to spend approximately $3000 for a new OEM PCM.

How to Prevent “Stop/Start Not Ready Battery Protection Mode” Message?

To prevent the “Stop/Start Not Ready Battery Protection Mode” message, you can take the following steps:

  1. Drive your vehicle regularly: If you don’t use your vehicle for extended periods, the battery may not receive a full charge, which can trigger the message. Regularly driving your vehicle can ensure that the battery is sufficiently charged.
  1. Avoid short trips: Short trips don’t allow the battery to charge fully, as the alternator needs more time to recharge the battery. If possible, combine multiple errands into one trip to allow the battery to charge sufficiently.
  1. Maintain the battery: Regularly inspect the battery for signs of corrosion or damage. Keep the battery terminals clean and tight to ensure a good connection.
  1. Check the charging system: If you notice any warning signs like dimming headlights or slow cranking, have the charging system checked by a professional. A weak alternator can prevent the battery from charging properly, which can trigger the message.

Frequently Asked Questions (FAQs):

Do I have to use a stop/start battery?

Yes, you do have to use a stop/start battery because your Jeep uses ESS and it comes with an auxiliary battery. You may disable the ESS, but the auxiliary battery must be used. 

Can I replace stop/start battery with normal battery?

No, you cannot use a normal battery to replace the auxiliary battery in your Jeep. Batteries not designed to handle the power and cycling requirements of idle stop/start systems should not be used in vehicles fitted with them.

Does start and stop drain battery?

No, the start/stop system does not drain the battery. The start/stop system uses the battery, which gets recharged automatically while driving.


Stop/Start Not Ready Battery Protection Mode Jeep error message does not mean something serious if it goes away on its own after some time. But if it does not, it means there is a problem with the battery or the charging system.

If the diagnosis and the solution instructions are beyond your skill level, you should get your vehicle to an experienced mechanic immediately. Once the problem is solved, maintain your battery and charging system on a regular basis to avoid such error messages in the future.

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