F150  Charging  System  Service  Now!  It’s   Alarming

The F150 charging system service now indicates that your vehicle requires prompt attention. This usually involves thorough inspection and servicing of the alternator, battery, voltage regulator, drive belt, wiring connections, and the PCM. This typically implies significant issues with these components and the charging system that require urgent attention. 

So, here I will guide you regarding the causes of the F150 charging system service now and how to fix the issue. 

Causes  And  Fixes  of  F150  Charging  System  Service   Now

Charging system service now is mainly a warning message that shows on the dashboard of the Ford F150 truck. This indicates a problem with the alternator, battery, and other electrical components of the charging system. 

Now, let’s see the reasons for this alarm and also their fixes. Have a look at the table below!

Reasons Solutions Cost 
Faulty alternator/voltage regulatorReplace the alternator/voltage regulator. Alternator: $623-$703 Voltage regulator: from $191-$218
Faulty battery and terminalRecharge or replace the battery$273-$282
Wiring issueCheck the wiring connection of the alternator to PCM and battery using a voltmeter. If there are any issues with the wiring, take the help of a mechanic.Totally depends on the area/workshop and complexity of the job
PCM Problems Reset your PCM or change it.$694-$810
Drive/serpentine belt issue Replace the damaged serpentine/drive belt connected to the alternator.$90-$110

Let’s start with the details of these problems and fixes. 

Reason 1: Faulty  Alternator/Voltage Regulator

When the engine runs, the alternator recharges the battery and also provides electricity to the system. If the alternator gets defective, it won’t charge the battery properly. 

Some symptoms of a faulty alternator are:

  1. Dim headlights
  2. Dim dashboard lights
  3. Interior lights flickers
  4. Strange noises coming from under the bonnet

Most of the time a bad alternator is the main problem of these symptoms. 

Diagnosis of Faulty Alternator/Voltage Regulator

You can be sure if the alternator is actually faulty or not by performing the following diagnosis:

Diagnosis 1: By Disconnecting Battery Terminal

You’ll need to be careful because you’re going to test a hot-running engine. Before testing it, wear heat-resistant rubber gloves.

The process for Diagnosis of The Faulty Alternator/Voltage Regulator by Disconnecting The Battery: 

Step 1: Open the hood to access the battery.

Step 2: start the car and let it idle.

Step 3: You’ll find the positive and negative terminals of the battery easily. Because they are colour coded. The positive terminal is red with the (+) sign and the negative terminal is black coloured with the (-) negative sign.

Step 4: Disconnect the negative terminal while running the engine. 

(Note: Remember not to disconnect the positive terminal from the battery. It may cause electrical damage to your system.)

Step 5: If the engine is still running normally after disconnecting the negative terminal, that means your alternator is good. But if the engine performance drops or completely stops, then it indicates a faulty alternator. 

So, that’s how you can test your alternator by disconnecting the negative terminal. 

However, if you want to be more sure about your alternator’s health, testing it with a multimeter will give you a more accurate result

Diagnosis 2: Using A Multimeter/Voltmeter

To test the alternator with a multimeter, you’ll need to have a multimeter ready. 

The process for Diagnosis of The Faulty Alternator/Voltage Regulator by Using The Multimeter/Voltmeter:

You will test the alternator both with the engine off and on. 

Now, the following are the steps for diagnosing the faulty alternator 

Step 1: Move to the engine bay and use the multimeter to measure the battery voltage. Place the negative lead on the negative battery terminal and the positive lead on the positive terminal. This is to check if the charging system is charging properly. 

Step 2: Locate the alternator and its connector and then check the voltage on the battery post of the alternator using the multimeter. If the reading is the same as the battery voltage, the alternator is not charging.

Step 3: Access the alternator’s battery post. Measure the voltage on the V+ terminal study at the back of the alternator while the engine is running. The voltage reading should be higher than the battery voltage, indicating charging. If it is not, then you should be confirmed that the alternator is not charging.

Step 4: Refer to the wiring diagram to understand the charging system components and their connections. Identify the three wires on the alternator connector.

Step 5: The grey and red wire is the battery voltage feed.  Check for system voltage at this wire using the multimeter. The power should be greater than the ones measured at the battery and alternator battery post voltage. If it is then the fuse is not blown. The alternator is then getting the current properly. Further verifying that the alternator is not working properly. 

Step 6: At this point, you can confirm that the alternator is faulty and requires replacement.  

For a visual demonstration, you can check this FORD F150 ECOBOOST CHARGING SYSTEM SERVICE NOW DIAGNOSIS. 


If you find that your alternator or the voltage regulator is bad, replace the respective component as soon as possible. You should seek professional assistance to replace these components if you don’t have enough expertise in automobiles.

Cost to Replace The Alternator/Voltage Regulator 

The average cost for an F150 alternator replacement is between $623-$703. The labor and parts cost will be approximately $87-$110 and $536-$593. The cost of the voltage regulator of F150 is $191-$218.

The cost of the voltage regulator of the F150 will start from $32.99.

Reason 2: Faulty Battery

You might have a faulty battery that is triggering the warning. The battery of the Ford F150 lasts for around two to five years. If you don’t have a new F150 then you should check the battery for the “charging system service now” warning.

The following are the common symptoms of a bad battery:

  1. Slow engine crank
  2. Dim headlights
  3. Warning lights on the dashboard
  4. Electrical issues (radio, power windows, etc.)
  5. Swollen or leaking battery case
  6. Low battery voltage


For checking the battery quality, you’ll need a multimeter/voltmeter.

However, the process of checking the battery’s health is identical to the alternator testing. You just need to follow the below table to identify the battery’s health.

Battery ConditionVoltage ReadingCourse of Action
Good Battery12.6V to 12.8VBattery is in good condition
Bad Battery11V to 12.2VNeeds to recharge the battery
Dead BatteryBelow 10.5VNeeds to replace the battery

[Note: The above voltage reading should be taken when the engine is turned off]


It’s a good idea to check the battery terminals before changing the battery. Corroded or loose battery terminals can cause problems with the battery’s performance or prevent the car from starting, even if the battery is otherwise in good condition.

To check the battery terminals:

  1. Inspect the terminals for signs of corrosion or damage.
  2. If there is corrosion, you can clean the terminals with a wire brush and a mixture of baking soda and water.
  3. If the terminals are loose, you can use a wrench or pliers to tighten them.

If the voltage reading still remains below 10.5V even after fixing the battery terminals, replace the battery.

Cost to Replace The Battery

The average cost of a replacement battery for F150 is $273-$282. The labour cost will be $32-$41. And the parts will cost approximately $241.

Reason 3: Wiring Issue

The wrong wiring issue can create the problem of “charging system service now”. You’ll have to notice the wiring connection of the alternator going to PCM and the battery. Because this type of problem occurs in F150 vehicles when the wiring is damaged.


To diagnose the wiring, you’ll need a multimeter.

Step 1: Inspect the wiring

Check the wiring for any visible signs of damage, such as frayed or corroded wires. Make sure that all connections are tight and secure.

Step 2: Use a wiring diagram

Use a wiring diagram to locate the charging system wiring harness.

Step 3: Check for continuity

Continuity refers to the ability of electricity to flow through a wire without any interruption or resistance. To check for continuity in the wiring, you will need a multimeter. Follow these steps:

  1. Set the multimeter to continuity mode.
  2. Touch one probe to one end of the wire and the other probe to the other end of the wire.
  3. If you hear a beep or see a reading on the multimeter, it means that there is continuity in the wire.
  4. If there is no beep or reading, it means that there is a break in the wire and it needs to be repaired or replaced.

The resistance value for a wire with good continuity should be close to zero. If you see a resistance value that is significantly higher, it could indicate that there is an issue with the wiring, such as a break or damage.

Step 4: Check for shorts

A short occurs when electricity flows through an unintended path or circuit. This can cause damage to the wiring or other components in the charging system. To check for shorts in the wiring, you will need a multimeter. Follow these steps:

  1. Set the multimeter to resistance mode.
  2. Touch one probe to one end of the wire and the other probe to a ground point (such as the negative terminal of the battery).
  3. If the resistance value is close to zero, it means that there is a short in the wire and it needs to be repaired or replaced.
  4. If the resistance value is high or infinite, it means that there is no short in the wire.

The resistance value for a wire with a short should be close to zero, indicating that electricity is flowing through an unintended path. If you see a high resistance value or an infinite reading, it means that the wire is not shorted and is likely functioning properly.


Attempting to test the wiring yourself without the proper knowledge or tools can be dangerous and can potentially cause further damage to the vehicle’s electrical system.

If you don’t have wiring knowledge or experience with using a multimeter, it’s best to seek the assistance of a professional mechanic or electrician. They will have the necessary tools and expertise to accurately diagnose any issues with the wiring and make any necessary repairs.

Reason 4: PCM Problem 

The powertrain control module (PCM) controls the charging system and different kinds of sensors to ensure the engine is running properly. So, if the PCM malfunctions it can cause the warning of charging system service now. 

PCM Failure symptoms 

  1. Low gas mileage
  2. Transmission issue
  3. Check the engine light
  4. Irregular shifting
  5. Engine stalling


To diagnose your PCM, you’ll need some tools. 

  1. Screwdriver
  2. Multimeter
  3. Flashlight
  4. Diagnostic scanner 

Step 1: Examine the wire

Check the PCM’s wires if they are damaged. You’ll need to replace them if you find any problems.

Step 2: Scan for error codes

Scan the PCM error codes with the diagnostic scanner. If you find any error codes like P0606, P060A, or P0603. Repair it as soon as possible with the help of a technician. 

Step 3: Examine the transmission

One of the major causes of F150 PCM failure is irregular shifting. It occurs due to water damage and a faulty sensor in your vehicle’s PCM. If you find that your automatic transmission is not shifting regularly then you’ll need to contact an expert mechanic as soon as possible. 


You can reset your F150 PCM before replacing it with the new one. It may solve your PCM problem. So, let’s know the steps and how you can reset it easily. You’ll need some tools-

  1. Socket 

Resetting of F150 PCM

  1. Open the truck’s hood. 
  2. Loosen the locknut beside the negative wire of the battery and then Remove it. 
  3. Go inside the car and turn on the headlights and set a timer for 20 minutes to drain and the backup power of PCM will reset it. 
  4. After that reconnect the negative wire to the battery terminal again.
  5. Tighten the locknut with the socket. 
  6. Lastly, close your truck hood and test your module by scanning again. You’ll not find any error codes if you can reset it successfully. 

Now if the reset doesn’t work for your vehicle then you can replace the PCM with the new one. Let’s check the steps below to replace your F150 PCM.

Replacement of PCM 

You’ll need to remove the PCM power relay and power diode before performing the replacement. And another thing to notice, you’ll have to buy the new PCM matching your old module’s number, barcodes, mounting location and connector. 

Step 1: Open your truck’s hood. 

Step 2: Remove the negative battery terminal. 

Step 3: Now find the PCM. It is located on the passenger side of the engine compartment.

Step 4: Take note of the number that is printed on the PCM.

Step 5: Match the number again with the new one and then, remove the old module carefully 

Step 6: Install the new module and reconnect the negative battery terminal. 

Cost to Replace The PCM

For a new powertrain control module, The average cost will be $694-$810. The labour and parts cost will be approximately $66-$87 and $628-$727 respectively.

Reason 5: Drive/Serpentine Belt Issue

Failing the serpentine belt can be one of the causes of the charging system service now warning. The serpentine belt helps the alternator to function. The alternator will not charge the battery if the serpentine belt gets defective.


Check the serpentine belt. This belt can get loose, worn out or damaged. 


If you find your vehicle’s serpentine belt is defective then you will have to replace it with a new one. Let’s now replace it with the following steps. 

(Note: before starting the process you may collect a good belt routing diagram if you need)

Equipment Required:

  1. 1/2″ drive ratchet
  2. Breaker bar (optional)
  3. Stretch Belt Remover/Installer


Step 1: Turn off your vehicle and remove the plastic cover on the top of the engine. 

Step 2: Find the belt tensioner under the hood. It looks like a pulley with an arm. You can use the images below to locate them.

Step 3: Use your 1/2″ drive ratchet or belt remover tool to rotate the tensioner clockwise towards the driver’s side to release the tension.

Step 4: Unhook the serpentine belt from the tensioner pulley by holding the tensioner tool in at the same time in place. Once it’s off one pulley, release the tool and remove it from the rest of the pulleys.

Step 5: Take the new belt and begin to conceal it around the various pulleys as shown in the diagram beneath.

You can also refer to the video to know the correct routing path- 5.4L Ford F-150 belt routing

Step 6: Install the new serpentine belt. Loop the new belt onto all pulleys except the tensioner. Use your 1/2″ drive ratchet or belt remover tool to loosen the tension on the pulley and slide the belt onto the last pulley.

Step 7: The last and most important step is to tension the serpentine belt correctly  by rotating the tensioner pulley counterclockwise. This can vary depending on the engine size. 

However, to check the tension of the serpentine belt on a Ford F150, locate the widest span of the belt and twist the centre area approximately half a turn. If it twists more or less than half a turn, it needs adjustment. Once the belt tension is adjusted correctly, the process will be completed.

Step 8: Once you’ve successfully replaced the serpentine belt successfully, put everything back in place in the reverse order. And then start the engine for a while to check if everything is working properly. If you notice any issues with the serpentine operation repeat the process. 

with this process, you can install the new serpentine belt on your alternator. For a better understanding, you can watch the video. 

However, replacing the serpentine belt is a complicated and long process. If you don’t feel comfortable with performing these steps it’s better to have it fixed by a professional automobile expert.

Cost to Replace Ford F150 Serpentine Belt 

You’ll have a new drive belt for an average of $90-$110. The labour and parts cost will be $39-$49 and $41-$60.

Can  I  Drive  With  “Charging  System  Service  Now”?  How  long?

Driving with the alarming “charging system service now” is very risky and dangerous. If your F150 truck shows the warning, there is a small chance to drive for a minimum distance. Because your battery is almost out of power.

It could die at any time while driving an F150 and leave you in an accident. As soon as you see the alarming signs on the dashboard and warning light, make a call to a mechanic to fix it. Otherwise, you also can check every part following the above discussion. 

If there is the least charge remaining, then you may drive for 30-60 minutes. And the electrical system will start to fail slowly if the battery is not being charged. 


What is the most serious warning light in a car? 

The most serious warning light in a car is the “ check engine light”. This indicates the serious and major engine damage to the car. If you ignore the warning light, your vehicle could suffer from a seized engine. You should take immediate service of your engine before it occurs. 

What are the two major dashboard warning lights?

The two major dashboard warning lights are red and orange. Generally, the red warning light indicates a serious issue with your car. The problem could be an overheating engine, low engine oil pressure and braking system problem. The orange light indicates a problem with the engine management system. The computer which runs the engine may be faulty or damaged.  

Can I drive with a bad alternator? 

It is not advised to drive with a bad alternator. This case is serious for new vehicle models. Because there is more electricity in a new vehicle than the older one. You will need to replace your alternator soon before your battery dies. 


Thank you for being till the end. I tried to show you the major causes and fixes for the alarming “charging system service now”. I hope it will help you to fix your problem and you will seek help from a technician if required. 

That’s all for today. Good luck!

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William Baldwin

This Is William Baldwin, The Founder & Managing Editor of this website. Me and my team share automotive tips, tricks, and news

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Talha Atta

Talha Atta, a Mechanical Engineer and experienced technical content writer and editor at Autoglobes.com with a passion for the automotive industry.