Full Accessory Power Active Car Won’t Start | Causes & Fix

Do you know how to turn off the full accessory power active mode in your Ford Fusion, Edge, f150, Explorer, Mustang, or any other model? In my experience, you may face problems starting your car due to this mode. But you don’t need to worry about it anymore.

I’ll guide you on how to turn off the accessory mod, and then you can drive the car quickly after clearing this with your own hands. First, we should understand what accessory power active means, its features, and the purpose of this mode.

What full accessory power active in Ford vehicles?

Modern vehicles introduce advanced technological features with time to improve user convenience and vehicle functionality. It helps to enhance the user experience by providing them with helpful and advanced features.

One of these features is full accessory power, which is active in Ford. It helps improve fuel efficiency and noise reduction and increases engine components’ lifespan by reducing wear and tear.

This message on your car’s dashboard indicates that your car’s electrical systems are active while the engine is not running. It allows drivers and passengers to use radio, windows, and lights without turning the engine on.

You can use electrical accessories like a mobile phone and laptop charging without starting the engine. 

How do you turn off Ford’s full accessory power Is active mode?

Turning off the accessory mode is a simple, straightforward process which can be performed by following the below steps:

• Firstly, resting your vehicle for a few minutes or half an hour is enough.

• Secondly, Press the engine start/stop button without pressing the brake pedals.

• Thirdly, press the brake paddles and click the engine start/stop button.

• For vehicles with the manual essential function, turn the key to the first position after pressing the brake paddles.

Finally,  I hope you’ve recovered your Ford car from accessory mode and it has been started for taking a long drive. Additionally, you can follow the instructions in the video below for better visual understanding.

Causes of accessory power active message

Here are the common possible causes that trigger the accessory message on the dashboard:

1. Battery issues
2. Software glitches
3. Electrical issues
4. Ignition issues
5. Electric control unit (ECU) issues

Battery Issues

If your Ford’s vehicle battery is weak, failed, or too old, it can trigger the accessory power active message. Battery is one of the most critical components in the electrical systems of any vehicle.

Sometimes, I see that many people don’t focus on the condition of their car’s battery, and when it is fully damaged, it also affects other electrical parts in the engine.

Software Glitches

Incomplete software updates, corrupt data, and bugs in programming are the leading causes of software glitches. Software issues are found when the electric control unit (ECU) fails or malfunctions. 

Electrical Problems

When the circuits, electronic components, and wiring are damaged or loose, then it might cause the accessory system to remain on while you want to turn it off. These electric issues can disrupt the normal operations of radios, windows, and lights, which may lead to several problems.

Ignition Issues

It might be possible that the ignition switch or its components are faulty or malfunctioning, triggering the full accessory power active message. When your ignition switch is not turning off the engine completely, it will drain the battery, and electrical accessories remain powered even when the key is removed.

Electric control unit (ECU) issues

A faulty electrical control unit, also known as the brain of the computer system, can appear as an accessory power light. When the ECU becomes defective, it sends incorrect signals to a computer system, forcing it to perform actions according to the provided signals.

Solutions of full accessory power active in Ford

Here are the solutions to all the causes that will help you protect your vehicle from these types of electric issues in the future.

Inspect battery condition

First, start monitoring the battery condition; if the battery is not fully charged, then charge it first. Then, take a lot of time on both terminals and clean them if necessary. If your Ford car battery is weak or old, you should replace it quickly because it can disrupt your journey and cause several faults.

Additionally, extended use of the navigation system, charging devices, and listening to music or radio without the engine running can still drain your battery. Limiting accessory power use if your battery is not charged enough is advised because it can automatically shut down the accessory power after a certain period.

Updated Software

Ensure that the software is updated with routine maintenance service. If there are bugs in it, then reprogramme from a certified technician. Additionally, I suggest you inspect the software with the help of error codes or a fault scanner. 

Replace Ignition Switch

Inspect the ignition switch and its components and ensure all parts function correctly and efficiently. When the ignition switch is damaged, and its parts show signs of fear, replace it with a high-quality new one.

After changing the parts, ensure that the electrical system turns off properly when the engine is off and not draining the battery.

Use Genuine Parts

Always use genuine, high-quality parts that are compatible and durable and perform for a long time. Genuine parts also improve engine working efficiency and keep the ECU to deliver information to the computer accordingly.

Inspect Electrical Systems

Repair or replace the damaged or cut affected wires, tighten the loose connectors, and ensure they appropriately supply current to the accessory systems. Now, you can verify that the accessory components function correctly by connecting a charger, turning on the lights, and using the windows.

Diagnosis With a scan tool

A diagnosis scan tool is the best way to pinpoint the exact part indicating the accessory power active. This tool runs a quick scan and identifies the errors. Mechanics solve all the errors individually, and the overall vehicle becomes fault-free.

Also, read about that famous warning known as: Check Injection System

Focus on maintaining your Ford vehicle’s electric system with regular maintenance and routine mechanic service is essential. However, the accessory power active is a normal function in Ford models, and it is not a king of malfunction that can impact the entire ECU.

Educating yourself about warnings, mechanical issues, and faults will improve your efficiency in detecting a problem.

FAQ – Frequently Asked Questions

What is “full accessory power active” in Ford vehicles?

It is an advanced function in Ford vehicles that indicates that you can use electrical system features like radio, windows, lights, and charging without the need to turn on the engine.

My car won’t start due to the “full accessory power light in Ford”?

First, rest your car for a half hour or 1 hour. Then, press the engine start/stop button to turn on the accessory power mode. Now, press the brake paddles and engine start button.

How do you turn on the electrical system?

Click on the engine start/stop button without pressing the brake paddles. This action will turn on the electrical system even if the engine remains off.

What does “accessory power” mean?

It means that the electrical system is active while the engine is off.