How to replace a car battery temperature sensor

The battery has a battery temperature sensor that can fail if the Check Engine light comes on, the battery voltage is low, or the RPM curve rises sharply.

Over the past 10 years, the evolution of sensors and control equipment has intensified. In fact, in many new vehicles, the new battery temperature sensor is an important component in helping the vehicle keep the battery charged. As some mechanical components and functions are being replaced by electrically controlled and powered units, having a fully charged battery becomes more and more important to the operation of a vehicle. It is for this purpose that these new vehicles have battery temperature sensors.

As the name suggests, the battery temperature sensor's job is to detect the temperature of the battery so that the charging system voltage can supply power to the battery as needed. This process not only ensures that the battery does not overheat, but also reduces the resistance of the electrical system; improving the overall efficiency of the vehicle. During periods when the battery temperature is low, the electrical system (alternator) increases the power supply to the battery. At high temperatures, the opposite is true.

Like any other sensor, the battery temperature sensor is subject to wear and tear. In most cases, battery temperature sensor problems are caused by corrosion or a buildup of dirt and debris that affects the sensors' ability to effectively monitor and report temperature. In some cases, the problem is solved by simply removing the battery and cleaning the sensor and wiring harness connector. Other instances require replacement of this component.

Part 1 of 2: Determining the Symptoms of a Bad Battery Temperature Sensor

The battery temperature sensor is designed to last the life of the vehicle, but debris or contamination will cause premature wear or failure of this component. If the battery temperature sensor is damaged or fails, the vehicle will usually display several general warning signs or symptoms to alert the driver to a problem. Some of the common signs of a damaged battery terminal sensor include:

Engine speed curve risingA: In most cases, the car's battery does not affect the operation of the engine after the car is started. In fact, the rest of the components are powered by an alternator or voltage regulator. However, if the battery temperature sensor is damaged, it can lead to an electrical failure in the ignition system. The battery has low voltage: When the temperature sensor cannot accurately determine the temperature of the battery, it triggers an OBD-II error code that will usually cut off the voltage system from the alternator to the battery. If this happens, the battery voltage will slowly decrease because it has no recharge source. If this is not corrected, the battery will eventually drain and will not be able to start the car or power accessories if the car's engine is turned off.

Check Engine light on dashboard: Normally, when error codes are stored in the ECM, the Check Engine light comes on and comes on in the instrument panel. In some cases, the battery indicator on the dashboard also comes on. The battery indicator usually indicates a problem with the battery charging, so it can also be a sign of other electrical problems. The best way to determine the exact cause of the warning light is to download the error codes stored in the ECM using a professional digital scanner.

If you notice any of these warning signs, it's a good idea to connect a diagnostic tool to the port under the dash to download the error codes. As a rule, two different codes are displayed when the battery temperature sensor is damaged. One code indicates a shorted battery temperature sensor and back for short periods of time, while another code indicates a complete loss of signal.

If the sensor intermittently shorts out, it is usually caused by dirt, debris, or a bad sensor wiring connection. When the signal is lost, it is often due to a faulty sensor that needs to be replaced.

The battery temperature sensor is located under the battery on most vehicles. It is recommended that you purchase a service manual for your vehicle to learn the exact steps to locate and replace this component on your vehicle as it may vary between individual vehicles.

Part 2 of 2: Replacing the Battery Terminal Sensor

On most domestic cars, the battery temperature sensor is located under the battery box and is located directly below the battery. Most batteries generate excess heat towards the bottom of the core and often in the middle of the battery, so the temperature sensor is located in this location. If you have determined that the problems you are experiencing are related to a faulty battery temperature sensor, gather the appropriate tools, spare parts, and prepare the vehicle for service.

Because the battery needs to be removed, you don't have to worry about lifting the car to do the job. Some mechanics prefer to lift the car and do the job from below if the battery temperature sensor is connected to the electrical harnesses below. For these reasons, it is recommended that you purchase a service manual specifically for your vehicle; so you can read and develop the attack plan that best suits your individual application and the tools and supplies you have.

According to most maintenance manuals, this job is pretty easy to do and takes about an hour. However, since a faulty battery temperature sensor likely caused the error code and is stored in the ECM, you will need a digital scanner to download and reset the ECM before attempting to start the vehicle and check for repairs.

Necessary materials

• Replacing the battery temperature sensor
• Socket set and ratchet (with extensions)
• Box and open-end wrenches
• Safety glasses

• Protective gloves

• Attention: In some cases, a new suspension is also required.

Step 1: Remove the air filter housing and engine covers.. On most vehicles with a battery temperature sensor, you will need to remove the engine covers and air filter housings. This allows access to the battery and battery box where the temperature sensor is located. Follow the manufacturer's maintenance instructions for removing these components; proceed to the next steps below.

Step 2: Loosen air filter connections to throttle body and remove. After you have removed the engine cover, you need to remove the air filter housing, which also covers the battery compartment. To complete this step, first loosen the clamp that secures the filter to the throttle body. Use a socket wrench or socket to loosen the clamp, but do not completely remove the clamp. Loosen the throttle body connection by hand, being careful not to damage the filter body. Grasp the front and back of the air filter housing with both hands and remove it from the vehicle. As a rule, the case is attached to clip-on buttons, which are pulled out of the car with sufficient force. Always refer to your service manual for exact instructions as some vehicles have bolts that need to be removed first.

Step 3: Disconnect the positive and negative battery cables from the terminals.. The best way to complete this step is to use a socket wrench to loosen the battery cables. Start with the negative terminal first, then disconnect the positive cable from the battery. Set the cables aside.

Step 4 Remove the battery harness clamp.. Typically, the battery is attached to the battery compartment with a clamp, which often has a single bolt.

In most cases, you can remove this bolt with a socket and extension. Remove the clip and then remove the battery from the vehicle.

Step 5 Locate and remove the battery temperature sensor.. In most cases, the battery temperature sensor is flush with the bottom of the battery compartment.

It is connected to the electrical connection and can be pulled out through the hole in the battery compartment for easy removal. Simply press the tab on the electrical harness and gently pull the sensor out of the harness.

Step 6: Clean the battery temperature sensor. We hope you were able to download the error codes before completing this process.

If the error code indicates a slow and gradual loss of signal, clean the sensor along with the wiring, reinstall the device and check the repair. If the error code indicates a complete loss of signal, you need to replace the battery temperature sensor.

Step 7 Install a new battery temperature sensor.. Connect the new sensor to the wiring harness and reinsert the battery temperature sensor into the hole at the bottom of the battery compartment.

Make sure the temperature sensor is flush with the battery compartment, as it was when you removed it earlier.

Step 8: install the battery. Connect the battery cables to the correct terminals and secure the battery clamps.

Step 9. Install the battery cover and air filter back to the vehicle.. Fasten the throttle body mount and tighten the clamp; then install the engine cover.

Replacing the battery temperature sensor is a simple job. However, different vehicles may have unique steps and different locations for this component. If you are not comfortable doing this repair yourself, ask one of AvtoTachki certified mechanics to replace the battery temperature sensor for you.