What Does Full Accessory Power Active Mean? (100% Fixed!)


What Does Full Accessory Power Active Mean?

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So, you’ve stumbled across the term “Full Accessory Power Active” and are wondering,

What Does Full Accessory Power Active Mean? Simply put, it refers to a vehicle state where all electronic accessories—like your car stereo, lights, windows etc.—have power even when the engine is off.

This feature allows drivers to enjoy these amenities without having to keep their engines running. But there’s much more behind this handy automotive functionality that we’re going to delve into in this article.

What is Full Accessory Power Active Mean?

Accessory power refers to the electricity supply that operates vehicle accessories. It’s a term often used in the automotive industry.

  • Main Function: Keep car electronics running when the engine isn’t on.
  • Examples: Radio, lights, climate control systems.

How it Works

  1. Turn off your car’s engine.
  2. The accessory power continues operating specific systems within your vehicle.

Note: The duration of accessory power can vary based on different factors such as battery condition and energy consumption of devices being powered.

Factors Impacting DurationDescription
Battery ConditionA healthy battery tends to provide longer accessory power
Energy ConsumptionHigh-energy consuming devices drain the battery faster

Remember that excessive use may lead to draining your car’s battery!

How to Fix the “Full Accessory Power Active”?

Here are the simple 3 steps to fix it:

  • Let your car cool down for a bit—though not sure if it helps, that’s what I did.
  • Press the Start button without touching the brakes.
  • Then, hit the brakes and press Start again.

Here we you have fixed it.

Why Won’t My Car Start in Full Accessory Power Active?

What Does Full Accessory Power Active Mean?

There are a few reasons why your car might be stuck in “Full accessory power active” and not starting:

Simple culprits:

  • Battery: A dead or weak battery is the most common reason. Check your headlights or other electronics; if they’re dim, the battery is likely the issue. Jump-start the car or use a multimeter to confirm voltage (12.6V+ is good).
  • Key fob: For keyless ignition, a weak fob battery can prevent starting. Try a spare fob or replacing the battery.
  • Brake pedal: Make sure you press the brake firmly while trying to start the car. Some vehicles require this for safety.

Deeper issues:

  • Electrical problem: The “Full accessory power active” message can indicate your car is stuck in accessory mode and not transitioning to ignition or start. This could be due to a faulty sensor, wiring issue, or problem with the ignition switch.
  • Starter issues: A failing starter motor might not engage the flywheel properly, preventing the engine from cranking. This would require professional diagnosis and repair.

Troubleshooting steps:

  • Soft reset: Disconnect the negative battery terminal for a few minutes, then reconnect it. This can sometimes clear electrical glitches.
  • Hard reset: Disconnect the battery and touch it to the positive terminal for a few seconds (erases radio presets and other settings, so be cautious).
  • Scan for DTCs: Use an OBD-II scanner to check for Diagnostic Trouble Codes that might point to the specific problem.

Here’s a video to fix this error:

Understanding Active Accessory Power:

Active Accessory Power (AAP) is a vehicle’s feature that provides power to the accessories, like the radio or power windows, even when the ignition is turned off. Here are some key points about AAP:

  • It allows you to use certain features without starting your car.
  • Not all vehicles have this feature; it depends on make and model.
  • The duration for which AAP stays active can vary.

Let’s understand more with a simple comparison table:

Without AAPWith AAP
Can’t operate electronic accessories when engine offCan operate electronic accessories when engine off
Less drain on battery while parkedMore potential drain on battery if accessories used excessively

And here are some steps of how Active Accessory Power works in most cars:

  1. Turn off the ignition.
  2. Notice that you can still use functions like electric windows or radio.
  3. After opening and closing driver’s door, these functions will disable themselves.

Remember – continuous usage of accessory power may lead to quick battery drainage. So be mindful!

Importance of Full Accessory Power:

What Does Full Accessory Power Active Mean?

Full accessory power is a term often heard in the automotive industry. It speaks to how cars are adapting for modern technology. Here’s why it matters:

  • Safety Features: Many safety features like airbags, emergency brake systems rely on full accessory power.
  • Convenience: It allows users to use electronic devices such as radio, GPS without starting the car engine.

Let’s dive deeper into each point:

Safety Features

  1. Airbags: They deploy using electrical signals sent when sensors detect an impact.
  2. Emergency Brake Systems: These need electricity to operate effectively and quickly in an urgent situation.
FeatureNeeds Full Accessory Power
Emergency Brake SystemYes


Imagine you’re waiting in your car and want to listen music or use GPS navigation but don’t want to waste fuel by starting the engine! That’s where full accessory power comes handy!

Note: Always remember that excessive usage might drain your vehicle battery!

How Does Full Accessory Power Work?

Full accessory power refers to the state of a vehicle where all accessories like radio, lights, and air conditioning receive power even when the engine isn’t running. So how does this work? Let’s dive in.

  • Ignition Switch Positions: The ignition switch has several positions:
    1. Off
    2. ACC (Accessory)
    3. ON
    4. Start

In the ACC position, full accessory power is active allowing users to utilize car accessories without starting the engine.

  • Relay Circuit: When you turn your key or press start button to ACC position, it activates a relay circuit that provides electricity to auxiliary components.
  • Battery Role: Your car battery provides necessary electricity for these features during this phase.

Here’s a simple table summarizing roles of key players:

Ignition SwitchActivates relay circuit on ACC position
Relay CircuitConnects battery with auxiliary components
BatteryProvides needed electricity

Keep in mind while it’s convenient, prolonged use can drain your vehicle’s battery!

Components Involved in Active Accessory Power:

Active Accessory Power (AAP) system comprises a set of crucial components. They are designed to ensure seamless power supply for your vehicle’s accessories even when the ignition is off.

Key Components:

  • Battery: The source of all electric power in your car.
  • Ignition Switch: Controls power distribution to different parts of the car.
  • Accessory Relay: Manages current flow between battery and accessories.

Here’s an overview:

BatteryStores electrical energy and supplies it as needed.
Ignition SwitchDetermines whether the AAP should be enabled or disabled based on ignition status.
Accessory RelayActs as switch, allowing or preventing current from reaching accessories depending on signals received from ignition switch


  1. When you turn off your car but leave the key in accessory position, AAP kicks into action.
  2. Current flows from battery through accessory relay to respective gadgets
  3. Once key is removed/turned further, signal goes to relay which then cuts off power supply.

In sum, these pieces work together to make up this handy feature that keeps our radios playing and phones charging even when engine isn’t running!

Benefits of Having Full Accessory Power:

Full accessory power brings numerous benefits to the table. Here are some key advantages you can enjoy:

To summarise these benefits in a clear and concise manner, refer to this table below:

ConvenienceUse accessories without starting the engine.
ComfortAdjust climate controls in any weather condition.
Battery LifeKeeps battery active and may prolong its life.

Common Issues with Accessory Power Activation:

Access to power accessories in your vehicle can sometimes have issues. Here are the most common ones:

  • Ignition Switch Failure: The primary issue often lies with the ignition switch itself.
  • Faulty Wiring: Damaged or worn-out wiring often leads to accessory power activation issues.
  • Blown Fuse: A blown fuse can prevent power from reaching the accessories.

Let’s dive deeper into these problems, and how they impact your vehicle’s functionality.

Ignition Switch Failure:

The ignition switch controls power supply to various car systems. A faulty switch may not effectively distribute power, leading to some accessories not functioning correctly. Symptoms include:

  1. Car stalling while driving
  2. Difficulty turning on accessories

Faulty Wiring:

Wiring connects all electrical components of a car together. If wires corrode or become damaged, they might interrupt the flow of electricity causing failure in accessory activation.

Signs you’re dealing with faulty wiring include:

  1. Flickering lights
  2. Accessories not working intermittently

Blown Fuse:

Fuses protect electrical circuits by breaking connections when there is too much current flow which could cause damage otherwise.

A blown fuse could lead to no accessory operation at all that includes:

Loss of lightNo interior/exterior lighting
Non-functional radioNo audio output

Troubleshooting Full Accessory Power Problems:

If you notice your car displaying “Full Accessory Power Active,” don’t panic. Here’s a brief guide to help you troubleshoot potential issues:

  • Check Battery Life:
  • Use a multimeter to measure the battery voltage.
  • A reading below 12 volts might be an indication of a weak or dying battery.
  • Inspect Ignition Switch:
  • Look out for any signs of wear and tear, or damage.
  • If in doubt, consult with a professional mechanic.

Next, let’s understand some common error codes related to full accessory power problems. This can help identify what exactly is wrong:

Error CodeDescription
P0571Cruise Control/Brake Switch A Circuit Malfunction
B2799Engine Immobilizer Malfunction
U0155Lost Communication With Instrument Panel Cluster (IPC) Control Module


  1. Try turning off your vehicle completely, then restarting it after few minutes.
  2. Disconnect and reconnect the battery cables.
  3. Consult with an auto repair shop if the problem persists.

Remember that understanding these errors is key in finding solutions efficiently!

Maintaining and Extending Active Accessory Power:

To ensure your vehicle’s accessory power remains active, follow these steps:

  1. Regularly run your vehicle: Vehicles need to be used frequently to keep the battery charged.
  2. Invest in a high-quality car battery: A good quality battery lasts longer and provides reliable accessory power.

If you are looking for ways to extend the life of your active accessory power, consider these tips:

  • Adjusting settings: Some vehicles allow you to modify how long accessories stay on after turning off the engine. Check the owner’s manual for instructions.
  • Battery maintainer: If you don’t use your car often, a maintainer can keep the battery at optimal charge.

Here is a comparison between two popular methods of extending active accessory power:

Battery MaintainerKeeps battery at optimal charge; Ideal for cars not used regularlyRequires purchase; Extra effort required for setup
Settings AdjustmentFree; Can be done on most modern cars without additional equipmentMay drain more energy if not monitored

Remember that each method has its own set of pros and cons. Choose wisely based on your needs and circumstances.

Best Practices for Using Full Accessory Power:

Full accessory power active mode is a term associated with vehicles, particularly those that are keyless. It’s the state where all accessories like radio, lights and windows work even though the engine isn’t running.

Here are some best practices when using full accessory power:

  • Don’t leave your vehicle in this mode for an extended period of time to avoid draining your battery.
  • Always check to ensure you’ve not accidentally left it on.

Keeping Your Battery Healthy:

Your car battery’s health is critical when frequently using full accessory power. Here are ways to keep it healthy:

  1. Regularly drive your car: This charges your battery.
  2. Keep it clean: Dirty batteries might drain faster.
  3. Monitor its age: Older batteries may need more maintenance or replacement.

Here’s a simple table showing how often you should consider checking these things based on average usage:

Average UseDrive CarClean BatteryCheck Age

Remember, taking care of your vehicle can mean lesser problems down the road!

Conclusion and final thoughts 💭

In a nutshell, “Full Accessory Power Active” is a vehicle’s state that permits the operation of all electrical components without starting the engine.

It’s an indispensable feature for those times when you want to listen to your favorite tunes or charge your phone without keeping the engine running.

Remember, while this function can be incredibly convenient, it’s crucial not to overuse it.

Extended usage could drain your car battery and leave you stranded. Keep these points in mind next time you see “Full Accessory Power Active” on your dashboard; now you know what it means and how best to utilize this feature!

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