Why Is My Check Engine Light On After Battery Replacement?

As you hit the road after a new battery change, the hope of improved overall vehicle performance fills the air. But that hope is shattered with a sudden illumination of the check engine light.

What could be the reason for the illumination of the check engine light after a battery change? While it seems like there’s no connection between these two events on the surface, they are related, and the check engine light can appear after a new battery change. This may leave you wondering, did I damage something in the process, or is there something I didn’t do right?

Read on to find out why you have a check engine light after a battery change on Nissan, Toyota, Ford, or your specific car model.

how to reset check engine light after battery change

Why does the check engine light come on after changing a battery?

The check engine light can come on after changing the battery because the new battery is undercharged or faulty or a car sensor cannot detect it. But if the check engine light is blinking, it could be due to a wrong electrical connection preventing the battery from receiving enough electric flow (of at least 13.5 volts) from the charging system.

Don’t freak out when you see this light. It doesn’t mean you have damaged the car engine or blown anything in the electrical system.

Here’s how the battery and the check engine light are related.

The check engine light (CEL) is connected to the engine control module, which is connected to the battery sensor, many other car sensors, and the battery management system (BMS).

The work of the engine control unit is to ensure your engine works as it should at all times. To achieve this, it collects data from several car sensors and components, including the battery management system, to process and control their functions.

The battery sensor constantly supplies accurate data to the engine control unit, such as the battery voltage, current, state of health, temperature, and state of charge. Whereas, the battery management system (BMS) makes precise adjustments on necessary parameters to optimize the overall battery performance.

If the battery sensor detects anything wrong, it will relate the information to the engine control module, which will trigger the engine warning light, alerting you that there’s something wrong and you should check it out.

The check engine light after a battery change on Ford, Chevy, or any car model may be due to an undercharged or faulty replacement battery. Also, a bad connection can stop the battery from charging or at least reduce the electric flow that gets to the battery, preventing it from receiving at least 13.5 volts when charging.

Or, it could be that the battery sensor is yet to detect the new battery. Thankfully, you can fix this by driving the vehicle a few cycles or wiping off the logged error code with a diagnostic scanner.

Can a new battery cause a check engine light to appear?

Yes, installing a new battery can cause the check engine light to appear on the dashboard. However, this typically happens when the new battery is of poor quality, undercharged, and considered low enough to carry all electrical and electronic components or when the battery terminals are loose.

If you install a new battery with less than 75% charge, the sensor will interpret this as an abnormality and signal the engine control unit, which will pop the engine warning light.

It’s not news that some battery shops sell poor quality batteries with less than 75% charge. If the check engine light appears due to poor quality battery, then you must replace the battery. If, however, it appears due to an undercharged battery, recharge it before putting it in your engine.

check engine light after battery change toyota

Can the check engine light reset on its own?

Yes, the check engine light can automatically reset on its own after 10-20 cycles if you have fixed the issue that triggered the warning light in the first place. A cycle is the process of turning the engine on, running it for some time, and turning it off. On some cars, you may have to run the car for 50 to 100 miles before the light resets.

This is a long period. So, to avoid the wait time, clear the light with a diagnostic scanner. The light will disappear instantly. If, however, you clear the warning light without fixing the problem that caused the light to appear in the first place, it will reappear in no time.

Do you have to reset the car computer after changing the battery?

Sometimes, you will need to reset your car computer after changing the battery, especially if the ECU triggered the CEL because the sensor did not detect the new battery. Most times, resetting the ECU/ECM will help the sensor detect the new battery.

Also, if the vehicle settings are not saved in the battery management system, you need to reset the power windows, the radio presets, and the clock after changing your car battery.

How can I prevent the check engine light from coming on after a battery change?

You don’t have much control over preventing the check engine light from coming on after a battery change. However, you should ensure the battery you want to install is fully charged, the terminals are corrosion-free, and properly tightened. Also, you can reset the warning light manually or with a scan tool once they appear after changing your battery.

How do I reset the check engine light after replacing the battery?

Whether you see the check engine light after a battery change on Chevy Silverado, Ford, or any car model, you can fix it manually or use a diagnostic trouble scanner. Here are how to reset check engine light after battery change;

  • Ensure the battery is fully charged and the terminals are properly tightened and corrosion-free.
  • Disconnect the negative battery terminal and leave it disconnected for 30-60 seconds.
  • Put the key into the ignition and turn it to the ON position 3 times before starting the engine.
  • Keep driving for 10 to 20 cycles.
  • Clear the error codes with a diagnostic scan tool.

Final Words

Having a check engine light after a battery change can be quite unnerving and frustrating—you don’t know if it is a minor or major issue.

A recap! Check engine light after battery change on Ford Focus, Chevy Traverse, Toyota Camry, or any car model simply means you have an undercharged battery, faulty battery, loose battery connections, or the car computer just needs to be reset. Whatever the root cause may be, just follow the guidelines in this article and fix it.

Osuagwu Solomon

Osuagwu Solomon is a certified mechanic with over a decade of experience in the mechanic garage, and he has over five years of experience in the writing industry. He started writing automotive articles to share his garage experience with car enthusiasts and armature mechanics. If he is not in the garage fixing challenging mechanical problems, he is writing automotive repair guides, buyer’s guides, and car and tools comparisons.

2 thoughts on “Why Is My Check Engine Light On After Battery Replacement?

  1. Hey Steve, thanks for reaching out.

    What’s the error code you got?

    Ensure the terminals are tighten and corrosion-free. After that, wipe the logged error codes and the light will disappear.

  2. I had change the battery and it told me on my scan tool not ready for smog , had to due the drive cycle to get it smog ready . What a pain took forever.

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