Can A Weak Battery Cause Transmission Problems? Here’s How!

Hi, I'm Luis Johnson, an automobile technician, and power equipment professional. By profession, I'm a businessman and operate a car workshop. I have created this...Read more

A car’s transmission is responsible for transforming the engine’s power into action. However, have you ever thought about what might happen if the battery that powers the transmission becomes weak?

A weak battery can create a chain reaction of electrical problems in your car, which can affect the transmission system’s functionality. In this blog, we will discuss the question that is on every car owner’s mind “can a weak battery cause transmission problems?”

Don’t worry if you are having issues with your car’s transmission just because of a weak battery; we’ve got you covered. Read till the end to know how a weak battery can create transmission issues and how you can fix that.

Can Weak Car Batteries Cause Transmission System Issues?

In modern vehicles, the transmission system is powered by electricity. The battery provides the necessary electric power to run every electric component of your car. Although the battery is not directly connected to the transmission due to electric regulation, transmission is affected by a weak battery.

Can A Weak Battery Cause Transmission Problems

When a battery is weak, it cannot provide enough voltage to internal computers that control the transmission. As a result, your car transmission will not function properly.

2 Common Transmission Issues You May Face Because Of A Weak Battery

A malfunctioning transmission will show many symptoms and indications, but when it comes to transmission issues caused by a weak battery, there are two common symptoms you can check.

Symptom 01: Transmission Entering “Fail Safe Mode”

Many modern cars feature a fail-safe mode that activates when the transmission system receives inadequate power. The transmission control module can switch to the fail-safe mode when the battery’s power output drops below a specific level, and the voltage fluctuates.

In this mode, the transmission operates in a specific gear and rpm and prevents any gear or rpm change to avoid damaging the engine.

transmission Entering Fail Safe Mode

Symptom 02: Inconsistent Shifting

When a weak or corroded battery struggles to provide sufficient voltage to the system, the transmission can shift erratically or inconsistently. You may notice unusual gear changes, delay in acceleration, or difficulty getting the car into gear.

How Can You Fix Transmission Issues Caused By Corroded Battery?

If you are experiencing transmission issues caused by a corroded battery, there are a few steps you can take to fix the problem.

Step 01: Confirm the Battery Issue

First, it’s important to identify the issue. If you notice that your car is having trouble shifting gears or there is delayed engagement, it may be a sign of a weak battery or corroded battery terminals.

Step 02: Check For Corrosion

Next, you should check the battery terminal and connections. If there is a lot of corrosion build-up on the battery terminals, especially the positive one, this can create bad connections and prevent the proper amount of voltage from getting to the transmission solenoids.

Check For Corrosion

Step 03: Clean Corroded Terminals

You should clean the battery terminals and remove any corrosion to fix this issue. Many different products are available for cleaning battery terminals, but a simple mixture of baking soda and water can also do the trick.

Clean Corroded Terminals

You can take help from a wire brush to rub the terminals until they are clean and corrosion-free.

After cleaning the terminals, test the voltage to ensure it’s within the suitable range. If the voltage is still low, it may be time to replace the battery.

After cleaning the terminals, test the voltage

Troubleshooting A Weak Car Battery

A weak car battery can cause various issues, from dimming headlights to transmission and difficulty starting the engine. If you suspect that your car’s battery is weak, here are some steps you can take to troubleshoot the issue:

How To Check For A Weak Battery?

  • Check the battery voltage: A voltmeter can help you to calculate the battery’s voltage. A completely charged car battery should read around 12.6 volts. If the battery voltage is below 12.4 volts, the battery may be weak and need charging.
  • Look for signs of corrosion: Check the battery terminals for any corrosion or buildup. Corrosion can cause a weak connection, affecting the battery’s performance.
  • Check the battery age: Car batteries typically last around 3–5 years. If your battery is older than that, you should replace it as batteries become weak over time.

Steps To Take If You Suspect A Weak Battery Issue

  • Replace the battery: If it is old and cannot hold a charge, it may be time to replace it. Be sure to choose the correct size and type of battery for your car.
  • Charge the battery: When the battery voltage is low, you can try charging it with a battery charger. You may need to jump-start if necessary.
  • Add Acid And Water: You can increase the voltage of your battery slightly by adding distilled water. It will make the acid more active. Sometimes you may need to add more sulfuric acid if the acid is low.

Best Practices For Preventing A Weak Car Battery

A weak car battery can cause inconvenience and frustration, especially if it fails when you need your car the most.

Fortunately, there are some best practices you can follow to prevent your car battery from becoming weak and extend its lifespan. Here are some tips to keep a healthy car battery:

  • Drive your car regularly: If you leave your car parked for long periods, it can cause the battery to self-drain. When you drive regularly, it can help keep the car battery charged.
  • Turn off electronics: When you turn off your car, be sure to turn off all electronics, such as the radio and lights. This can help prevent the car battery from rapidly draining.
  • Keep the terminals clean: Regularly cleaning the battery terminals can help prevent corrosion buildup and ensure a good connection.
  • Avoid the heat: Avoid Keeping your car in direct sunlight for a long. Otherwise, it will damage your car battery’s health.
  • Check the battery regularly: Inspect the battery voltage and water levels and look for signs of corrosion or damage regularly.

Frequently Asked Questions

Now that we’ve discussed transmission and battery issues and how to address them, here are some FAQ answers to help you with further doubts!

Is It Possible for A Faulty Battery to Trigger a Transmission Code?

Although a low-voltage battery may seem fully charged and able to start the engine, it can still affect the vehicle’s systems and result in error codes indicating a loss of communication.

What Sensors Are Likely to Cause Transmission Issues?

The ISS and OSS are two-speed sensors in a car that work together to display transmission data to the vehicle’s powertrain module.  Any misalignment in these sensors can cause transmission problems.

Why Did My Automatic Transmission Fail?

The most prevalent cause of automatic transmission failure is an inadequate amount of fluid that results in overheating. This eventually leads to delayed engagement, harsh shifts, and slippage in the transmission system.

Can a Weak Battery Damage Car Components?

A weak battery can adversely impact the electronic components of your car, including the car’s computer system. Insufficient power supply from a faulty battery can lead to computer problems, affecting its overall functioning.


Understanding the connection between transmission issues and a weak car battery is essential. A faulty battery can cause erratic shifting, slipping gears, and even complete transmission collapse.

If you detect any of these signs, bring your vehicle to a qualified mechanic for repair and diagnosis. It is also critical to properly maintain your car’s battery by regularly checking its voltage and keeping the connections clean and tight.

Keep in mind that the health of your car’s battery is critical to properly operating your transmission, so maintain it to avoid costly repairs in the future.

Hi, I'm Luis Johnson, an automobile technician, and power equipment professional. By profession, I'm a businessman and operate a car workshop. I have created this site Batteryquery to help people purchase the right battery for their vehicles. The reason behind creating this site is to help my customers purchase the right car battery who often purchase the wrong one due to their lack of knowledge.

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