If you see the message “Stop Start Not Ready Engine Temperature Too Low” in your car, it means the Stop/Start system is temporarily disabled due to the engine being too cold. 

This system helps save fuel by turning off the engine when you stop and restarting it when you release the brake. To resolve this issue, try running the engine for a few minutes to warm it up, especially in cold weather. 

If the problem persists, it might be due to a faulty thermostat, temperature sensor, or other issues. Consider consulting a mechanic for a thorough inspection and necessary repairs in such cases.

The Stop/Start system is in your Jeep to save fuel and reduce emissions by turning off the engine when the car is not moving. But what if it stops doing that and shows a message like “stop start, not ready, engine temperature too low”? It’s not a big problem if it happens briefly in icy conditions after starting your car. 

But if it keeps happening, especially in warmer weather, you might have a thermostat issue. This means the thermostat might be set at the wrong temperature. Having an expert check your car if the problem continues is a good idea.

What is a Stop/Start system?

If you’ve ever wondered about the Stop/Start system in your car, it’s a feature designed to save fuel by automatically shutting off the engine when the vehicle stops and restarting it when you release the brake pedal. 

This helps reduce fuel consumption and emissions, contributing to a more eco-friendly driving experience.

When your car stops at a traffic signal, the Stop/Start system switches off the engine. It turns back on when you press the clutch pedal or release the brake. While it doesn’t save a lot of fuel, this technology helps reduce noise and emissions, making driving more economical and eco-friendly. That’s why most new cars on the road have this system.

How does it work?

The Stop/Start system monitors various factors, including engine temperature, battery charge, and other vehicle conditions. When conditions are optimal, such as during brief stops, the system temporarily shuts off the engine to conserve fuel. As soon as you lift your foot off the brake, the engine restarts seamlessly.

The Stop/Start system is like a smart helper for your car. It talks to the car’s computer and knows when you stop. When you stop, it tells the car to take a break from using gasoline. 

The engine starts again on its own when you’re ready to go, like when you release the brake or press the clutch pedal. You don’t have to do anything special; it just happens automatically.

Read also: Jeep 4xe Electric Mode Temporarily Unavailable 

What Causes the Stop Start Not Ready Engine Temperature Too Low Warning?

If you’ve encountered the warning “Stop Start Not Ready Engine Temperature Too Low,” several issues may be at play.

For the engine to turn off when the car stops, certain conditions must be met, and one of these is the engine temperature. The auto stop/start feature works best when the engine is warmed up because starting it is easier and puts less strain on the starter motor. 

However, in very cold temperatures (below 27 °F) or very hot temperatures (above 95 °F), the engine may not turn off at all.

There are various reasons why the engine might not be reaching the required temperature.

Malfunctioning Thermostat

A malfunctioning thermostat can cause the engine to stay cooler than required, triggering the warning. The thermostat regulates the engine temperature; if it’s faulty, the Stop/Start system may not activate.

The coolant thermostat keeps the coolant from moving around when it’s closed, helping the engine warm up. This is important so the engine can reach its normal temperature for proper operation. 

However, if the thermostat goes bad or stays open, the coolant keeps flowing, making it hard for the engine to warm up.

Faulty Coolant Temperature Sensor

The coolant temperature sensor plays a crucial role in the engine’s operation. A malfunctioning sensor can provide incorrect temperature readings, preventing the Stop/Start system from engaging.

The sensor talks to the main computer that runs the stop/start system. It’s like a messenger, and one of the things it reports is the coolant temperature. The computer looks at all the information, including the temperature, to decide if turning off the engine is okay.

But the computer gets confused if the sensor doesn’t work right and gives the wrong information. It might think the engine is too cold, even if it’s not. So, to be safe, the computer stops the stop/start system from working until the sensor is fixed.

Malfunctioning Engine Coolant Temperature Gauge

If the engine coolant temperature gauge is not functioning correctly, it may not accurately reflect the actual temperature. This can lead to the “too low” warning, affecting the Stop/Start system.

If the engine temperature gauge in your car is broken or the needle is stuck because of wiring problems, it gives the wrong temperature. It might say the engine is cold even when it’s actually at the right temperature. When this happens, the Stop/Start system won’t work.

Blocked Radiator

A blocked or restricted radiator can hinder the engine from reaching the optimal temperature. This can result in the Stop/Start system remaining inactive due to the perceived low temperature.

The radiator helps cool the engine by circulating coolant when the car runs. But when you’re driving fast or the engine isn’t very hot, it’s not needed.

If the radiator gets stuck open due to a problem with a sensor or the wiring, it can make the engine stay too cool.

Freezing Conditions

In extremely cold weather, the engine may take longer to reach the required temperature. The Stop/Start system may stay inactive until the engine warms up sufficiently.

In really cold weather, the engine of your car needs some time to warm up to its usual temperature, especially when you start the car in the morning. Once the engine is warmed up, it can stay at that temperature without needing extra help during routine stops and starts. It takes a while for the engine to cool down once it’s warmed up.

Even when it’s freezing outside, the car’s engine can stay warm for a long time because it holds a lot of heat. Also, when the engine is turned off, the radiator stops working, which means it can’t take heat away from the engine. This helps the engine stay warm for an extended period of time.

How to fix the Stop Start Not Ready Engine Temperature Too Low warning?

If you encounter this warning, there are several steps you can take to address the issue.

If you bring your Jeep to the shop, they might say there’s no issue, and everything is okay. This is kind of usual. They’ll return it to you, saying to carry on. So, before you head to the shop, make sure you know what the auto Stop/Start needs to work. 

The engine needs to warm up and get to the right temperature. Check if the coolant, transmission, and engine oil temperatures are in the cool zone.

Replace Your Thermostat

If the thermostat is faulty, replacing it can restore proper temperature regulation, allowing the Stop/Start system to function as intended.

Check if your thermostat is stuck open. Make sure to use the right 195-degree thermostat for your engine. This will bring your engine to its normal 210-degree operating temperature, where it works best. 

If you don’t have the right thermostat, replace the existing one with the correct 195-degree type. Avoid those labeled “failsafe,” as they often fail to work properly. Also, stay away from thermostats with lower temperature settings, like 165°F or 180°F. 

If your Jeep is fully warmed up but the temperature gauge isn’t in the middle, it’s because your thermostat is stuck open. In that case, replace your stock thermostat with a 195 thermostat.

Read also: Service Electronic Throttle Control Jeep Warning

Replace the Coolant Temperature Sensor

Replacing a malfunctioning coolant temperature sensor can ensure accurate temperature readings, enabling the proper operation of the Stop/Start system.

If you’re certain that your engine is warming up like it should and the sensor is giving the wrong readings, then change the coolant temperature sensor.

Replace faulty Gauge

If the engine coolant temperature gauge is faulty, consider replacing it to provide accurate temperature information for the Stop/Start system.

If you’re sure your engine is getting warm but the temperature gauge isn’t showing it, you might have a broken gauge. Try replacing it, but make sure it’s installed correctly before doing so.

Check the Radiator and the Wiring

Ensure the radiator is not blocked or restricted, and check the wiring connected to the temperature-related components for any issues. Check that all connections are secure and there are no problems with the wires. 

Make sure the radiator is in good working condition. If you suspect the radiator fan is always on, test it. If the fan is not working properly, replace it.

Run the Engine for a While

In cold weather, allow the engine to run for a few minutes before driving. This helps raise the engine temperature, allowing the Stop/Start system to activate.

If you get the error message, start the engine for a bit, especially if it’s cold. That usually fixes it. If the error keeps showing up, there might be a bigger issue. In that case, check the parts mentioned earlier.

What’s the danger?

While the “Stop Start Not Ready Engine Temperature Too Low” warning is more inconvenient than dangerous, it can affect fuel efficiency. The Stop/Start system is designed to enhance fuel economy, and if it remains inactive, you may experience slightly higher fuel consumption.

Driving your car at a low temperature can cause significant damage. It might make your car use more fuel, so it’s important to check and make sure you have enough gas to avoid running out. 

You might notice that your car also doesn’t work, and your engine could start to wear out. If you see an error, it’s crucial to take quick action to address the issue.

Should You Go to a Mechanic?

If the issue persists or if you’re unsure about diagnosing and fixing the problem yourself, it’s advisable to consult a mechanic. They can perform a thorough inspection, identify the root cause, and implement the necessary repairs to ensure the proper functioning of the Stop/Start system.

If your car’s Stop/Start system doesn’t work, it’s important to pay attention when it happens. If it continues to not work even after driving for more than 20 minutes or if the weather isn’t too cold, there might be a problem. It could be the thermostat or a battery issue. To be sure, it’s a good idea to take your car to the dealership before it breaks down somewhere. 

A regular mechanic with a good scanner can also check if it’s just a minor issue and not something more serious.

Some Other Reasons for Stop/Start Not Working

Other factors may impact the Stop/Start system besides temperature-related issues. Low battery charge, a malfunctioning starter motor, or issues with the vehicle’s electrical system can also prevent the system from activating.

Sometimes, the Stop/Start feature in your car might not work correctly, and it usually shows a message on the display to explain why. There are different situations that can affect the Stop/Start:

• If the driver’s door is open,
• When the battery is too warm or too cold.
• If the battery doesn’t have enough charge,
• When the driver’s seat belt is not buckled.
• While the car’s cabin is cooling or heating.
• If the transmission is not in forward gear,
• When the car hood is open.
• If the brake pedal is pressed softly,
• When the engine temperature is too high.

These are some reasons why the engine might not turn off automatically. The system checks various safety and comfort conditions before deciding whether to shut off the engine. 

You can find detailed information about the Stop/Start system’s operation on the instrument cluster display.

Pros and Cons of Dealing with Stop Start Not Ready Engine Temperature Too Low

Dealing with the “Stop Start Not Ready Engine Temperature Too Low” warning has its pros and cons. On the positive side, when the Stop/Start system is active, it boosts fuel efficiency and reduces environmental impact by minimizing emissions. The system also automatically adjusts to colder temperatures, ensuring it operates optimally. 

However, there can be initial delays in colder weather, and persistent warnings in warmer conditions might indicate underlying issues, possibly affecting fuel consumption temporarily. For a quick overview, the table below summarizes the advantages and disadvantages of handling this warning.

Pros	Cons
1. Improved Fuel Efficiency	1. Initial Delays in Cold Weather
2. Reduced Environmental Impact	2. Possible Thermostat Issues
3. Automatic Temperature Adjustment	3. Temporary Warning Message
	4. Potential Fuel Consumption Increase

This table provides a concise comparison of the benefits and drawbacks associated with addressing the “Stop Start Not Ready Engine Temperature Too Low” warning.

Future Improvements for Addressing Stop Start Not Ready Engine Temperature Too Low Issues

In the future, we can expect enhancements to address the “Stop Start Not Ready Engine Temperature Too Low” issues more effectively. 

Manufacturers may develop smarter technologies to quickly adapt the Stop/Start system to various temperature conditions, ensuring smoother operation even in colder weather. 

These improvements aim to provide a hassle-free driving experience, minimizing the occurrence of warnings related to engine temperature.

FAQs

What happens if the engine temperature is too low?

If the engine temperature is too low, it can lead to decreased fuel efficiency, increased emissions, and poor overall engine performance. It may also prevent certain systems, like the Start/Stop feature, from engaging until the engine reaches an optimal temperature.

Why is my car running at a low temperature?

Your car may run at a low temperature due to issues with the thermostat, coolant temperature sensor, or radiator. A malfunction in these components can disrupt the proper regulation of engine temperature, impacting performance and triggering warnings.

What does start stop not ready mean?

“Start Stop Not Ready” typically means that the Start/Stop system in your car is temporarily disabled. This can happen if the engine temperature is too low, the battery charge is low, or if there’s a malfunction in related components. The system automatically turns off the engine when the car is stationary and restarts it when you resume driving to save fuel.

What coolant temperature is too low?

The coolant temperature considered too low can vary depending on the vehicle and operating conditions. Generally, if the engine operates below its optimal temperature range, it can affect fuel efficiency and emissions. In some cases, a warning like “Stop Start, Not Ready, Engine Temperature Too Low” may indicate that the coolant temperature is below the level needed for certain systems to function efficiently.

Final Words

If you see the “Stop Start Not Ready Engine Temperature Too Low” warning.

Don’t panic. Understanding the potential causes and solutions discussed here can help you address the issue. Regular maintenance and prompt attention to any warning lights will ensure that your Stop/Start system continues to contribute to fuel efficiency and environmental friendliness.

In cold weather, it takes a bit of time for the Stop/Start feature to work. It’s normal, especially during the winter. When the engine is cold, the Stop/Start won’t activate, and you might see a warning message saying, “stop/start not ready engine temperature too low.” 

The car’s computer knows it’s best to let the engine warm up before using the Stop/Start. If you still get the error message after driving for a while or in hot weather, there could be an issue with the thermostat or something else. In that case, follow the earlier steps or ask your mechanic for help.