How To Troubleshoot and Fix U0100 Code Dodge Charger

The U0100 code is a trouble code that indicates the occurrence of communication failure between your Charger’s control modules. Since the control modules help run the car, U0100 means that your Charger can no longer perform as expected unless you resolve the issues.

Various issues, including damaged circuits, faulty modules, and a flat battery, can cause this code. If you notice signs like difficulty starting the engine or your check engine light turns on, you’re about to see code U0100.
Don’t Worry! Read on to learn about the causes of this code, along with how to diagnose and fix it.

What Is The U0100 Code?

Code U0100 is a diagnostic error code that means there are communication problems between your Charger’s control modules. Inter-module communication is facilitated by the Controller Area Network (CAN) bus.

If the powertrain control module (PCM) fails to communicate with other modules, code U0100 arises. The table below presents the idea of how to diagnose the code and fix it. It also shows the possible causes the code appears.

Causes of U0100 codeHow to diagnose U0100How to fix code U0100
Flat or dead batteryCheck the battery levelCharge the battery or replace it if damaged
Loose or damaged connectionsInspect the wiring harnessFix or replace any broken wires. If you can’t fix the harness, replace it
Faulty CAN busCheck the CAN bus and its connectionsClean and fix the CAN bus connections. If damaged, replace the bus
Damaged PCM Inspect the PCMIf your Charger’s issue is the PCM, seek professional help
Use the Charger’s technical service bulletin (TSB) to find out if there are related issuesAny issues listed in the TSB have corresponding solutions listed as well

Decoding U0100 Code Dodge Charger

Several problems can cause the trouble code U0100. Some of the most common ones that I have found mostly-

  • Damaged powertrain control module (PCM)
  • Flat or dead battery
  • A loose ground connection to the PCM
  • Faulty Controller Area Network (CAN) bus
  • Shortcircuits in the wiring harness

The Signs of Code U0100

Some of the common indications of a code U0100 are;

  • Your Charger’s check engine lights get illuminated
  • The engine may crank but refuse to start. In other cases, it will neither crank nor start
  • In cases where the issue happens intermittently, the engine will run fine but stall at random times
    Gas mileage may become worse
  • Sometimes you may feel the Charger engine producing less power than usual

How Do I Diagnose DTC Code U0100

Since the issues that cause code U0100 are many, you must diagnose to find out your Charger’s specific problem. This section will provide some possible ways to diagnose your car. You can go through them one by one.

  • Inspect the battery

Begin by inspecting the battery before you move to the other parts. If the battery is dead or flat, the PCM and other modules will not get any power. So the code will appear. Charge the battery or replace it with a new one and see if the code disappears.

  • Use PCM-related TSBs to diagnose

The first thing to do whenever you notice the error code U0100 is check your Dodge Charger’s Technical Service Bulletins (TSBs). These bulletins typically provide information about the common issues that your vehicle may have and how to fix them.

If the problem causing the code U0100 is listed in your car’s TSB, it will be easy to identify and fix. If you don’t have access to your Charger’s TSBs, you can find them online by specifying the model and year of manufacture.

  • Scan for other codes

If you don’t find your problem in a TSB, it’s a good idea to scan for other trouble codes. Often, code U0100 appears together with a few other control module trouble codes.

These extra codes will help localize the issue and make it easier to fix your car. A common code that appears alongside the U0100 is U0101. This indicates that the Transmission Control Module (TCM) has failed to communicate with the PCM.

  • Inspect the PCM wiring harness

After scanning for other codes, check the PCM wiring harness. Look for any wires that appear melted, burnt, worn out, or chafed. These problems usually manifest in places where the harness gets through corners, so start by checking there.

  • Check the CAN bus connections

If the wiring harness is working fine, the issue may be the connections to the CAN bus. In this case, the simplest thing to do is to find where the harness connects to the control module and unplug it. Inspect the pins because any damage to them can interrupt the circuit.

  • Inspect the PCM

If you still haven’t found the issue, inspect the PCM. Use a multimeter to check any connections and confirm that the module is receiving power. A PCM that receives power but doesn’t communicate is probably damaged and should be replaced.

Here’s a video about troubleshooting code U0100.

How To Fix U0100?

Depending on the problem, there are a few ways you can fix the error code. Follow the steps below.

Step 1. Charge your battery or replace it with a new one if it’s dead.

Step 2. If you discover another code, for example, code U0101, fix it first and see if code U0100 gets resolved too.

Step 3. Fix any damaged wires in the wiring harness. Use a cleaner to clean its pins and remove any dirt that may have accumulated on them. If that doesn’t work, swap it for a new wiring harness.

Step 4. If you discover a faulty PCM, you must replace it. PCM replacement is a delicate repair that may require you to find professional help.

What’s The Cost Of Fixing Code U0100?

The cost of fixing code U0100 depends on its cause. If the problem is a dead battery, a replacement will cost you about $200. Depending on your Dodge Charger’s year of manufacture, the average wiring harness cost ranges between $100 and $300.

PCM costs range between $400 and $900 depending on your car’s year of manufacture. If you prefer to have a professional replace the PCM, the average labor cost is about $400 for this repair.

Read More-

  1. What is the meaning of the P1217 Code on Dodge Charger
  2. How to troubleshoot P0430 Code Dodge Charge


Here are some answers to some common questions about code U0100.

Q: Can I drive my Dodge Charger with error code U0100?

No, you should never drive your car if you have a code U0100.  This is because communication failure between modules can lead to problems like stalling that may cause accidents.

Q: Can I avoid code U0100?

You can avoid code U0100 by getting your Charger checked and serviced regularly.

Q: How long does it take to fix the U0100 code?

It takes a mechanic an hour or two to troubleshoot and fix code U0100. If you decide to do it yourself, it may take longer to fix the issue, depending on your skill level.


The U0100 code indicates a problem with communication between your Dodge Charger’s modules. This code is commonly caused by faulty electrical connections and is characterized by issues like difficulty starting the car.

For the most part, you can troubleshoot and fix code U0100 by yourself. However, if the issue involves the PCM, you should seek professional help or contact us.


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