Dodge Check Engine ON

Dodge Check Engine Light Troubleshooting Guide

Updated Friday May 25, 2018

Is your Dodge check engine light ON? Your first thought is "Oh no, how much is this going to cost?". Take a deep breath and don't panic! In this guide, you will find information that can help you become familiar with some of the most common problems that trigger Dodge check engine light. You will also find instructions on how to read and clear Dodge check engine light using different OBD-II scanners.

It is important to not ignore your Dodge check engine light for weeks or months. What may be a simple fix such as a defective Mass Air Flow (MAF) sensor, if ignored can lead to more expensive problems. For example, a failed MAF sensor that is causing the engine to run rich can shorten the life of the catalytic converter which typically costs $800-$1500 to replace. 

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1. Why is my Dodge Check Engine Light On? 

Dodge Check Engine Light

If your Dodge Check Engine Light (CEL) is staying on when you start the car or comes on while driving it indicates that the On-Board Diagnostics (OBD) system has detected a problem. A solid check engine light does not always mean emergency but it is important to have the codes read as soon as possible. Ignoring the CEL warning light can cause more problems down the road. Also keep in mind that if your Dodge CEL/MIL light is on, your fuel economy may be lower and exhaust emission usually increase.  

Your Dodge check engine light can come on for various reasons. While it could be something as simple as a loose gas cap, there are over 1000 diagnostic trouble codes  (DTC) that can trigger the check engine light. Without reading the codes it is impossible to know what is wrong. Below you will find instructions on how to read codes yourself or where you can have them read for free. 

Here are some of the most common problem that can trigger Dodge check engine light. 

  1. A failed spark plug or ignition coil
  2. Mass air flow sensor needs to be replaced. 
  3. Loose gas cap or gas cap needs to be replaced. 
  4. Damaged catalytic converter. 
  5. Intake vacuum leak
  6. Leak in the EVAP system due to a cracked hose
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2. What to do when your Dodge check engine light comes on? 

If your Dodge check engine light is on, in most cases you can continue to operate the vehicle if there are no performance issues. 

1. Check dashboard warnings

Dodge dashboard warning lights

Check your dashboard warning lights and gauges. Make sure there are no warning lights for low oil pressure or engine overheating. Otherwise, drive with caution and continue to monitor how the car is running. If the engine sounds different, the problem may be serious and should be diagnosed immediately. 

  • If your Dodge check engine light is flashing, do NOT continue to operate the vehicle. 

2. Check gas cap

Dodge gas cap is not missing, it is capless design

Check your gas cap to make sure it is on tight. If you find that the gas cap was loose or removed, tighten it until you hear it click. After a few driving cycles, the light will turn off on its own because the ECU will keep on checking the EVAP system. Once it verifies there are no leaks present the ECU will reset the check engine light (also known as MIL).  It will take a few driving cycles for the light to reset and in most cases, the light resets within two to three days.

3. Monitor engine temperature

Dodge engine overheated Check Engine Light ON

Next, you need to monitor the engine temperature. If your check engine light came on because of an engine misfire, it is possible that the engine is going to overheat. If the engine does overheat, it can lead to a blown head gasket which can be a costly repair. Especially if your check engine light is flashing or blinking. 

  • If the engine is overheating or the oil light is ON, you should pull over and shut off the engine as soon as you can. 

4. Reduce speed and load

If your check engine light is on, reduce your speed and do not put unnecessary load on the engine. If you are towing a trainer either reduce the speed drastically or remove the load. 

5. Read fault codes

The next step is to read the fault codes. Even if you don’t notice a problem, you should still have your Diagnostic Trouble Codes (DTCs) read. For this, you will need a scan tool that can read OBD-II check engine codes. 

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3. How to read and reset Dodge check engine light

Let's take a look at how you can use various OBD II scanners to read codes and clear Dodge check engine codes. These instructions work on 1996 and newer Dodge vehicles such as Dodge Grand Caravan, Stratus, Viper, Challenger, Charger, Avenger, Caliber, Dart, Magnum, Neon, Durango, and Journey. 

Step 1: Locate OBD-II Port

Dodge OBD2 port location

Locate the OBD-II port under the dashboard on driver's side. Plug in your OBD-II scanner. 

Step 2: Turn on ignition

turn on dodge ignition

Turn on the ignition. It is not necessary to start the engine. If your Dodge has a Start/Stop button, press it twice without pressing the brake pedal to turn on the accessories and the OBD-II port. 

Step 3: Read codes

Read Clear Dodge Check Engine Light

The next step is to read the codes. Instructions on this step will vary depending on the scanner that you are using. For your convenience, we have provided videos on how to use various OBD2 scanners to read codes and clear Dodge check engine light. 

The first video shows how to use the MaxiScan scan tool to read and clear Dodge check engine light. 

What we used: MaxiScan MS309 Scanner

You can also use your smartphone and an OBD-II Bluetooth adapter to read and clear codes. 

What we used: ELM327 OBD-II Bluetooth Adapter

The scanners listed above only allow you to diagnose the check engine light. Next, we will take a look at a couple of scanners that can diagnose multiple systems on Dodge vehicles. First, we will look at Foxwell which is able to diagnose engine light but also ABS and airbag system. 

What we used: Foxwell NT630 Engine, Airbag, ABS Scanner

Lastly, we will take a look at how to use a professional diagnostic scanner to troubleshoot various systems on your Dodge. 

What we used: Autotel maxidas ds708


Clearing codes without fixing the problem that triggered the CEL, does not a proper solution. Always address the problem first then clear the check engine light. 

The scanners we use are only a few of the available scanners on the market. Most OBD-II scanners will vary in price from $30 up to $200. The more expensive scanners allow you to read codes from the airbag, Anti-lock Brake System and other control units, which you won't be able to accomplish with a generic OBD-II scanner. To learn more about OBD-II scanners and tips on choosing one, read the guide on Understanding OBD-II Scanners. 

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4. How to read Dodge check engine codes without a scanner

On a few Dodge vehicles such as Dodge Dakota and Grand Caravans, for example, you can retrieve the codes without a scanner. 

  1. Cycle the key in the ignition three times. Turn key to ON then OFF three times.
  2. Leave the key in the ON position.
  3. Wait five seconds. 
  4. A code will be displayed on the instrument cluster where your vehicle miles display. For example P0300. 
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5. Dodge Check Engine Light Flashes 10 Times

If you turn the key to ON position (or key in ACC position), but do not start the engine you may notice that the check engine light flashes 10x times. This happens if you recently disconnected the battery or used an OBD-II scanner to clear the codes. It means that one or more of the emissions systems is not ready, also known as the I/M readiness test. All the systems will be tested as you drive the vehicle, and the light usually stops blinking after a few driving cycles.

If your Dodge CEL flashes 10 times at startup continue to drive your Dodge and the light should stop blinking within a few days. Do NOT drive if the car, if the CEL continues to flash when the engine is running.  

It is important to understand that if your Dodge check engine light is flashing 10 times, and you take the car for an emission test, it will fail because at least one of the following systems is not ready: 

  • Ignition / Misfire 
  • Fuel System
  • Catalyst
  • Heated Catalyst
  • Evap System
  • Secondary Air System
  • Oxygen Sensor
  • Oxygen Sensor Heater
  • EGR System

Even if your check engine light turns off, but one or more of these systems is NOT READY, your Dodge is not ready for emissions testing. Once all the systems listed above are tested by the on-board diagnostic system and the car is ready for emission test, the check engine light will come on for a few seconds then turn off. It will not blink and should not stay on when the engine is running. 

If you think the light is flashing, 9 or 11 times, count it again. It should blink 10 times.

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6. Common Dodge CEL Codes

While there are hundreds of Diagnostic Trouble Codes (DTCs), we wanted to take a look at some of the most common fault codes that many Dodge owners may experience. 

Dodge P0456 Code

dodge P0456 codeThis code indicates a very small leak in the EVAP system. A common problem with Dodge trucks such as Dodge Ram gasoline engine is a rotted hose for EVAP system. The hoses from the fuel tank to the engine can crack over time. The problem could also be NVLD valve. Along with the P0456, you may also get P0440 or P0442. These are EVAP codes. If you have any of these codes, check the gas cap as well. 

Dodge P0456 & P0457 Code

Dodge P0456 P0457 codeIf the P0457 and P0457 codes come up and your check engine light is on, the first you need to do is to check or even replace the gas cap. If the code remains, there is a high chance that you have a defective leak detection pump. Your Dodge leak detection pump can be accessed from underneath the car. It can be replaced without removing the fuel tank. 

Dodge P0306, P0303 or P0300 Code

Bad spark plug triggered Dodge check engine lightThese codes mean that Engine Control Unit has detected an engine misfire. These codes can be caused by any of the following:

  • Bad spark plugs
  • Defective ignition coil
  • Fuel injector dirty
  • Mass air flow sensor
  • Damaged catalytic converter

These are just a few of the problems that can cause a cylinder misfire. To determine the cause of P03XXX codes, you need to perform further troubleshooting.

Dodge P1404 Code

This code is usually triggered by a defective EGR valve. The EGR valve may have a bad solenoid or carbon blockage. In most cases, the valve is replaced which is a job that most DIYers can tackle themselves. While it is not required, it is recommended to disconnect the battery while you replace the EGR valve. You can also clean the EGR valve but there is no guarantee that cleaning it will fix the problem. 

Dodge P0562 Code

The P0562 code can be triggered if low system voltage is detected. Along with the P0562 light, you may also get a red battery warning light on the dashboard. Newer Dodge vehicles may even go into limp (fail safe) mode when this code is present. Low voltage can be caused by a bad alternator or voltage regulator. It can also be caused by poor ground connection, corroded battery terminals, or battery that has a bad cell. If you read the codes and your Dodge has code P0562 address the problem as soon as possible. If ignored you may experience other problems such as engine refusing to start, poor fuel economy or transmission not shifting out of Park and into Drive. 

Dodge P0404 Code

If your Dodge check engine light is on and you get code P0404 it means that your Dodge Exhaust Gas Recirculation (EGR) valve is operating out of range. The purpose of the EGR valve is to recirculate exhaust gases and send them back into the engine to lower the NOx emissions. In a new Dodge EGR Valve costs anywhere from $50 to $200 and to replace it at the dealer in average you will pay between $300 and $550. The EGR is mounted on your Dodge engine near the exhaust. In most Dodge vehicles it is fairly easy to replace. This is a job that most DIYers can perform in their driveway as long as you have the correct tools. 

Keep in mind that the EGR valve itself may not always be the problem. The problem could also be the signal from the EGR valve to the engine ECU. 

This code has similar symptoms to a vacuum leak as well. Make sure to check the solenoid operation and wiring as well. You need to perform a continuity test on the wire harness to make sure the wire harness to the EGR is not defective.  

Some of the most common symptoms of the P0404 on Dodge vehicles include engine dying at idle, engine stalling or rough idle. This is a common problem on Dodge trucks such as Rams where in addition to the P0404 code you may also get the P0406 code. 

Dodge P0720 Code

A P0720 code is a generic transmission code. The code indicates that there is a malfunction of the output shaft sensor. The problem could be the sensor itself or the wire harness. Common symptoms include delayed shifting and the check engine light on. In some cases, a Dodge P0720 can also be caused by a defective transmission fluid temperature sensor. 

The sensor is mounted on the side of the transmission, towards the end. Note that the output speed sensor is also used as the input speed sensor on certain Dodge transmission. 

Check the current price on Dodge output speed sensor.

Dodge P0420 Code

If your check engine light is on and you get the P0420 code it means that the catalytic converter is working below efficiency. In most cases, the catalytic converter is the culprit but the problem could also be an oxygen sensor that is not working properly. One symptom of being a bad catalytic converter is that the vehicle may struggle to accelerate when you press the gas pedal. When this code is present the fuel economy decreases. 

Dodge P0441 Code

This code means evaporative emission control system has incorrect purge flow. A P0441 code on Dodge vehicles is often triggered by either a faulty purge control valve, purge solenoid or damaged purge solenoid wires. This problem can be caused by restrictions on the EVAP system or bad vacuum witch.

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7. Dodge Check Engine Light Repair Cost

When you call your Dodge dealer or any auto mechanic, you will be asked to bring the car in for a diagnostic. The reason is that they need to plug in a scan tool to read the codes from the ECU. This is a procedure that you can perform if you have the right tools. For this checkup, Dodge dealers charge between $80 and $130. If your Dodge is still under warranty, your Dodge dealer will perform diagnostic free of charge. Also, note that a few Dodge dealerships may offer free check engine light diagnostics. 

Just reading the codes is the starting point. Your dealer will make suggestions on the parts that need to be replaced based on the diagnostic results. The main advantage of taking your car to the dealer is that the scanner used at the dealership provides more detailed information than the code that you retrieve using a generic OBD-II scanner.

The diagnostic fee charged at the dealership or the mechanic does not include the cost to fix the problem. If you decide to have the car fixed at the same place that performed the diagnostics, ask the manager to waive the diagnostic fee. In most cases, they will if you ask in advance. 

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Check Engine Light Flashing

If your check engine light is flashing it means that the engine control unit has detected a misfire. You should stop as soon as possible and have your vehicle towed if necessary to prevent further damage to the engine or catalytic converter. 

What this means is that one or more of your cylinders are not working properly. This can be caused by a number of things such as bad spark plug, faulty ignition coil, bad ECU, clogged catalytic converter. 

If your car is flashing the check engine light and you continue to drive, you can damage the engine or the catalytic which can cost anywhere from $800 to $1500 to replace.

Top 10 Causes of Check Engine Light

Here is a list of the most common causes of Check Engine Light. Average costs to repair these problem has been included. Please note that for high-end vehicles the repair cost can be outside of this range. The repair costs shown below are typical prices you will pay at the dealers and auto repair shop. When a DIYer performs these repairs the average cost is significantly lower. 

  1. Oxygen Sensors 
    • Repair Cost: $200-$400
    • Repair Difficulty: Easy 
  2. Catalytic converter
    • Repair Cost: $750-$1500
    • Repair Difficulty: Moderate 
  3. Spark Plugs
    • Repair Cost: $250-$600
    • Repair Difficulty: Easy
  4. Loose Gas Cap
    • Repair Cost: Free - $25
    • Repair Difficulty: Very Easy
  5. Mass Air Flow MAF Sensor
    • Repair Cost: $200-$400
    • Repair Difficulty: Easy
  6. EVAP Purge Control Valve
    • Repair Cost: $120-$400
    • Repair Difficulty: Easy
  7. Ignition Coils
    • Repair Cost: $140-$600
    • Repair Difficulty: Easy
  8. Thermostat
    • Repair Cost: $200-$650
    • Repair Difficulty: Moderate
  9. Camshaft Position Sensor
    • Repair Cost: $150-$400
    • Repair Difficulty: Easy
  10. Fuel Injectors
    • Repair Cost: $350-$650
    • Repair Difficulty: Easy

Important Notes

  1. Clearing the check engine light using a scanner or by disconnecting the car battery does not fix the problem itself. Clearing codes without fixing the problem simply erases the codes from Engine Control Unit memory. Also keep in mind that if your car requires an emissions test soon after you clear the code, you will fail the emissions test. Clearing (CEL) codes also set the emissions readiness indicators to NOT READY. The car will require a few days of driving or a specific drive cycle to test all the emission systems and set them to READY.
  2. We recommend that you get a second opinion from a professional before you replace any parts. Do not replace car parts based on the fault code alone. It is important to consider the symptoms and the code before you come to a conclusion. For example, you may get a code for a bad oxygen sensor. While the oxygen sensor can surely be defective, a code for oxygen sensor can also be triggered by a cut wire, bad connector,  bad catalytic converter etc. Keep in mind that even a mechanic may have a difficult time diagnosing those rare cases. 
  3. If your check engine light turns on while driving continually monitor the engine temperature and oil pressure light. If any of these lights turn on, safely pull over and turn off the engine. 
  4. Do not ignore the Check Engine Light warning. Diagnose your vehicle as soon as possible.
  5. Auto parts stores such as Advance Auto Parts or AutoZone may offer free scanning of the Check Engine Light. 
  6. Check Engine Light (CEL) may also be referred to as Service Engine Soon (SES), malfunction indicator lamp (MIL). 

Frequently Asked Questions

Yes, disconnecting the battery usually clear the ECU codes. By turning the check engine light off this way you will not fix the problem. If you believe the check engine light needs to be off, drive the car for a few days and the CEL will reset itself. The Onboard Diagnostic System in your car continually monitors your vehicle and will turn off the CEL if the problem is solved. If the problem hasn't been resolved, even if you disconnect the battery, the CEL will come back up again which can be as soon as you restart the car or up to a few days.

If check engine light is on, it will not pass emission inspection/smog test. If the light was recently reset with an OBD2 scanner or by disconnecting the battery, you need to drive the car for a couple of days for the systems to be ready for testing.

It could be because you are using an OBD2 scanner that does not support the protocol used in your car. Try a different scanner. Also, there may be an issue communicating with the ECU due to a damaged wire or ECU malfunction.

No. The check engine light is not the reason why the car doesn't start. If the car doesn't start, read the codes and maybe the CEL will give you a code that can help you diagnose the car. Clearing codes will not make your car start.

It may be just bad timing. An oil change is not going to trigger the CEL. Unless MAYBE a sensor got accidentally unplugged, disconnected or damaged during the oil change. Take your car back to the auto repair shop that changed your oil and have them diagnose the problem.

No, the CEL should not turn on after routine maintenance. If you modified your engine, transmission, exhaust, intake, fuel system or other systems it can affect engine and emission control system, causing check engine or service engine soon light to come on. CEL should not come on if you changed tires or tire size.

Drive the car for a couple of days and allow the ECU to reset itself. If the CEL still remains on, read codes.

The check engine light is trying to tell you that there is a problem with your engine. It could be low coolant, stuck thermostat, transmission not shifting. Figure out why your car is overheating first and address that problem. DO NOT CONTINUE TO DRIVE IF YOUR CAR OVERHEATS.