What Does P305f Code Means on Chevy Malibu and How to Fix it?

The error number P305f refers to a malfunction with the Dual Battery Control Module Performance. The control module will switch between the two batteries as needed, whether it be to let one charge or to allow both to continue working despite the increased demand.

When you finally get the code, you may start to wonder exactly how the problem can be fixed. Not to worry, though! In this article, I will explain the p305f error message and show you how to fix it.

P305f Code on Chevy Malibu
P305f Chevy Malibu

What Does the P305f Code on A Chevy Malibu Mean?

The Chevrolet Malibu error code P350f indicates a problem with the dual battery control module performance.

It indicates that ECM has detected a faulty auxiliary battery voltage through the IGN input.

A P305F code is a diagnostic trouble code (DTC) that is specific to a certain manufacturer. It means that the car has a 12 V primary battery and a 12 V auxiliary battery.

The dual battery management module swaps between the two batteries at the right periods to accommodate vehicle loads and charging. At the beginning of the engine’s rotation, the auxiliary battery is activated to power the vehicle’s loads. P305F is set if the signal is not within the parameters.

I’ll explain the code in full in the section about the solution. For now, let’s look at what the code’s dissection means.

  • P-Powertrain. Everything that gets your car moving is part of the powertrain.
  • 3- Standardized SAE code.
  • 0-It indicates fuel and air metering controls as well as auxiliary emission controls.
  • 5f- Define a specific issue. Here it is Dual battery control module performance problem.

Why Does The Chevrolet Malibu Contain Two Batteries?

Auto-shutoff is standard on the Chevrolet Malibu. In order to conserve fuel, fluids, and wear and tear, your engine will shut down if it has been idling for too long or if certain other conditions are satisfied. With this, your Malibu’s gas mileage will increase significantly.

Your car’s main battery will be used to kick start the engine when you try to restart it. In order to start the engine without draining the primary battery, a secondary battery is installed to power the car’s interior lights, radio, and other electronics.

It’s a simple improvement to your quality of life, like not having to worry about missing your favorite portion of a song while your car restarts. The trunk is a convenient, out-of-the-way location for such a little battery.

How Serious Is This Code?

A P305F code is regarded as serious. It is advised that this issue be resolved promptly.

When a battery’s charge is too low, it cannot create sufficient power to start the car and will soon lose the ability to maintain adequate voltage for accessory loads. This implies that if your car’s battery is running low, you should have it charged or replaced as soon as possible to avoid being stranded or experiencing a system breakdown at high speeds.

What Causes Code P305f On Chevy Malibu?

Any number of things could have led to your car suddenly displaying the P305f code, leaving you to scratch your head and wonder what happened. Chevrolet Malibu P305f error codes may be caused for a number of reasons. However, the most frequent causes are:

  • Poor electrical connection within the battery circuit.
  • A bad auxiliary battery.
  • Low battery charge.
  • Defective battery control module.
  • A lose ground.
  • Ground wires are unclean and lose.
  • Battery harness is open or shorted.
  • Fretting and corrosion on female terminal pins in 4 pin connectors.
  • Nuts that hold fuses are loose (8-millimeter).

What Are The Chevrolet Malibu P305f Code’s Symptoms?

If the fault code p305f is stored in your Chevrolet Malibu, the vehicle will exhibit a number of symptoms.

Typically, the symptoms are so subtle that you wouldn’t notice them all at once. In certain instances, though, you may observe the following symptoms of this code:

  • Engine Light On (also known as the Service Engine Soon Warning Light)
  • The battery is not charging.
  • The engine cranks slowly or not at all (due to low battery power).
  • The Auxiliary or the primary battery is not providing enough power to start

How To Fix The P305f Code On Chevy Malibu?

Now let’s examine how to fix the Chevrolet Malibu error code p305f. You will need specific tools to complete the needed steps for repairing a malfunctioning twin battery control module.

Similar to tackling any other problem, you must first identify the precise cause of the issue. Test the components that caused this code in the first place.

The issue may originate from the wiring surrounding your primary battery, or it may originate from your trunk battery. Before purchasing a new trunk battery, inspect the engine compartment for any loose or missing parts. Here is what you are seeking:

  • Scan the ECM for fault codes and examine the freeze frame data. Check the battery to ensure no open circuits exist. Verify that the ECM transmits a voltage signal to the IGN. Replace ECM as necessary
  • A lose ground is located right in front of your primary battery. Remove any chafing that may be causing damage to your car’s wiring by checking the area around the battery. Replace any fuse nuts that you notice to be loose under the fuse box.
  • If everything seems to be functioning properly, open the trunk and remove the battery cover. If it hasn’t come off on its own, the next step will be to check the battery.
  • The nuts can be loosened with a tool that has a ten-millimeter opening. The cables should be installed after the mounting bolts have been put in place.
  • First disconnect the negative cable, then take out the battery, and then take out the vent tube in the top right corner of the battery.
  • Assuming you have access to a battery tester, you can go ahead and check the battery’s capacity. In the absence of a battery tester, it’s safe to assume that a faulty auxiliary battery is to blame for error p305f, and that replacing it is the best course of action.
  • Rerun DTC after repairs are made.
  • Due to the manufacturer-specific nature of this code, it is essential to consult your local dealer to ensure appropriate diagnosis and repair.

If you want a more in-depth explanation of the repair process, check out this video.

The following are possible solutions to this problem:

  • Get broken parts fixed or replaced.
  • Fix wiring harness
  • Battery Replacement (usually the auxiliary battery).

How Much Does It Cost to Fix The Chevy P305f Code?

P305F Chevrolet code diagnosis takes 1 hour. Labor costs to fix your car can change based on where you live, what you drive, and even what kind of engine your car has. Prices per hour at auto repair shops often range from $75 to $150.

The cost of replacements is given below-

  • Auxiliary battery replacement: $247
  • Battery cable replacement: $170 to $195
  • ECM replacement: $499 to $569

Note: Labor charges are included.

Can You Drive Your Chevy Malibu with Code P305f?

P305f is a diagnostic code for dual battery module performance. And with this error code, it is recommended to stop driving and repair this issue immediately.

This code indicates that ECM detected a faulty auxiliary battery voltage through an IGN input. Getting an error code of P305F is quite serious.

If a car’s battery is too low, it won’t have enough energy to turn over the ignition and won’t be able to keep up with the demands of the car’s accessories for long.

Frequently Asked Questions (FAQs)

What is the function of auxiliary battery in a Malibu?

The Auxiliary 12 battery supplies powers to the car’s electronics whenever the engine is turned back on.

What are the other codes related to code P305f?

P0A80 – Charging System Voltage Too Low
P1123 – Low Battery Voltage Detected

Why does the Chevrolet Malibu need two batteries?

A dual-battery isolation module makes sure that both batteries are charged properly and that the primary battery always has enough power to start the car.

What is the recommended battery voltage for a Chevy Malibu?

Current voltage ranges between 12 and 13 volts.

What if your auxiliary battery fails?

The electrical components and safety features of your vehicle will stop functioning if the auxiliary battery is defective.

Conclusion

Last but not least, the P305F code is a diagnostic error message that indicates the ECM is not receiving power from the car’s auxiliary battery.  There could be future starting and charging problems if this code is not properly diagnosed and repaired in a timely way. Just follow the methods mentioned in this article to get rid of it.

If you’re still having trouble after trying these methods, you should probably call in the experts or take it to a repair shop to have the complicated parts swapped out.

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