P1631 code — how to fix error fast

The P1631 OBD2 code is one of the most common codes you may encounter as a driver. While some drivers may dismiss it and blame it on poor electrical connections, it will inevitably affect the driveability of your car in more ways than one. So, to deal with this bothersome code, it’s essential to understand the P1631 code meaning and, most importantly, the reasons why it shows up.

As we realize you may be busy to play mechanic yourself, our team will deliver all the necessary pieces of information on this code and ways of fixing it. We’ll take a deep dive into the code’s commonly-encountered causes, means of prevention, and fixing methods that will help you permanently remove it.

Why you can trust REREV’s OBD2 code advice: Our automotive expert researchers with experienced mechanics undertakes a thorough research methodology to deliver precise insights on OBD codes. Find out more about OBD2 codes research process..

What does the P1631 code mean?

The P1631 code is a generic powertrain code that indicates a malfunction in the battery or charging system. When this code appears on your onboard computer, it means that the vehicle’s computer has detected a low voltage condition, which can be caused by a range of issues.

Your battery could be drained, damaged, or completely discharged and these conditions can be caused by a variety of different reasons. You may also be experiencing issues due to discharged battery that can’t keep the charge from the alternator, or you may be dealing with a parasitic draw due to electrical features in the cabin. Either way, it’s worth exploring the reasons to find an obvious solution.

What causes the P1631 code?

As mentioned, this code may have quite a few potential reasons behind it, so it’s no wonder that it takes exploring all of these to find a solution. Here are some of the most commonly-found culprits behind the code P1631:

Faulty alternator

The alternator is responsible for charging the battery while the engine is running. If the alternator is not functioning correctly, it can cause a low voltage condition, which triggers the code in cases where the battery can’t hold that charge.

Defective battery

A faulty battery can cause a low voltage condition and trigger the P1631 code. This often happens when the battery has a discharge condition, which means it can’t keep the voltage provided by the alternator and it simply keeps depleting regardless of how much the alternator charges it.

Loose or corroded battery cables

If the battery cables are loose or corroded, they can prevent the battery from properly charging, which can lead to a low voltage condition and trigger the code P1631.

Bad battery control module

The battery control module regulates the charging of the battery. If it’s not functioning correctly, it can lead to a lack of proper charging from the alternator and the usage of the battery’s electrical capacity won’t be properly established as it should.

Malfunctioning voltage regulator

The voltage regulator controls the amount of voltage supplied to the battery. If it’s not functioning correctly, it can lead to problems with the P1631 condition and you may even experience amplitudes in the operation of your car’s electrical components.

Which car models does the P1631 code affect the most?

The P1631 code can affect a wide range of vehicles, but it’s most commonly found in GM vehicles, including Buick, Cadillac, Chevrolet, GMC, Hummer, and Pontiac models. This is because these vehicles use a specific type of battery control module that is prone to failure. Still, we wanted to give you a more precise overview of these models, so here’s the final list:

• Nissan Altima: Some Altima owners have reported issues with battery voltage and drainage. These issues can be caused by a range of factors, including problems with the alternator or with the battery itself.
• Jeep Grand Cherokee: This is yet another car that may be affected by the code P1631 more than others due to issues with the voltage regulator and battery discharge.
• BMW 335i: The E92 BMW 3 Series is often affected by a range of electrical issues that may cause the code to trigger in this car.

How to diagnose the P1631 code

There are several ways of diagnosing this code in a way that highlights the precise reason why the code may have triggered in the first place. We decided to give you an overview of each so you can have an easier job figuring out a solution:

Check the battery

The first step is to check the battery voltage with a multimeter. If the voltage is low, the battery may be the culprit. In this case, it’s most likely that you’ll have to replace the battery to solve the issue, but you can also check for any parasitic draw to see if that’s what’s causing the trouble.

Inspect the battery cables

You can have a trusted mechanic inspect the battery cables for looseness or corrosion. If the cables are damaged, they will need to be replaced, and this often makes a fast and easy solution.

Test the alternator

You will have to test the alternator to ensure that it’s properly charging the battery since it’s often the cause of the code that slips under the radar for most drivers. By dealing with this issue, you can ensure that the alternator is properly charging the battery while the vehicle is running and this can be done with a multimeter.

Check the battery control module

If the battery and alternator are functioning correctly, the mechanic will check the battery control module for faults. It’s best if you leave this one to trained professionals to check the module as they will know when it’s necessary to replace it and when it should simply be reset.

Inspect the voltage regulator

If the battery control module is functioning correctly, the mechanic will inspect the voltage regulator for faults. Voltage regular may be the cause of improper power supply and dealing with this component can save you trouble in the long run.

How to fix the P1631 code

Fixing the code P1631 depends on the exact root cause of the problem and you can make things right by doing proper repairs of that component. So, once you’ve used the mentioned diagnostic methods, you can resort to the following fixing options:

Replace the battery

If the battery is faulty or suffers from a discharge condition, you’ll have to replace it with a new one to get rid of the code. It usually costs from $100 to $300 depending on the manufacturer and the type of vehicle you are driving.

Repair or replace the alternator

If the alternator is not functioning correctly, it may need to be repaired or replaced to fix the code. You’ll know this by testing the alternator with a voltage measurement tool and if it turns out to be faulty, it’s time to replace it to get the battery properly charged again.

Replace the battery control module

Another common reason behind the code is the battery control module fault and once again it needs to be replaced to sort out the code. We suggest you find an experienced mechanic for this task since it’s not advised even for automotive enthusiasts to tamper with the battery’s module and electrical connections.

Replace the voltage regulator

If the voltage regulator is faulty, it will need to be replaced with a new regulator and this can be relatively fast and affordable.

It’s important to note that the cost of fixing the P1631 code can vary depending on the make and model of the vehicle and the root cause of the problem.

How to prevent the P1631 code

Preventing the P1631 code requires routine maintenance and care of the battery and charging system. Here are some tips to help prevent the code from appearing:

• Regularly inspect the battery and charging system for damage or wear
• Replace the battery every 3-5 years
• Keep the battery cables clean and free of corrosion
• Have the alternator and voltage regulator checked during routine maintenance

By following these preventative measures, you can help ensure that your vehicle’s battery and charging system remains in good condition and prevent the P1631 code from appearing.

Our take

Overall, the code P1631 can be much more dangerous than it seems if you let it affect the car’s starting system or if the battery depletes completely while driving. To prevent having to deal with vehicle stalling or problems starting the engine at first, it’s essential that you deal with this problem by addressing the root cause.

Hopefully, this can easily be done with the help of our automotive experts and a trusted mechanic, so make sure to use this article as your guide.