Cummins Check Engine Light But No Codes - What Can Be Wrong?

If your Dodge Cummins' check engine light appears, the first thing you are likely to do is to check for accompanying error codes. They are the easiest way to find out what kind of problem you are facing. Consequently, a check engine light with no codes can have a deer-in-the-headlights effect on many drivers. You simply do not know what to do next. Don't stress out because we have you covered.

This article will tell you everything you need to know about the check engine light with no codes scenario and then some solutions. Read on to learn more about:

• What to do when your check engine light flashes without any codes stored
• What is causing your check engine light to come on without any codes
• Solutions to the problems causing the check engine light but no codes scenario
• How to fix a check engine light with no codes

Can You Drive Your Dodge Cummins When the Check Engine Light is On But No Codes?

If your Dodge Cummins is not manifesting other signs of engine trouble, e.g., stalling or misfiring, nothing is stopping you from driving it. Just because you can, does not mean you should. Cautious drivers would never drive their car past the dealership or their repair shop of choice once the check engine light turns on.

Your check engine light is also known as a malfunction indicator lamp and only turns on when your ECU, PCM, or ECM detects an abnormality. When an ODBII code does not accompany the check engine light, driving your Dodge Cummins is a bad idea because you cannot isolate the cause of the problem.

It is not advisable to drive around with a malfunctioning engine, especially when you have no clue what the problem could be.

Causes of Check Engine Light Without Stored Codes in Your Dodge Cummins

Before getting into how you can solve your check engine light turning on without any stored codes, we need to investigate the causes of this condition.

1. Incompatible or Damaged Code Scanner

Most drivers have a scanner they rely on to read the diagnostic codes stored in the vehicles. There are a wide variety of code scanners on the market, and not all of them are of equal quality. If your scanner has been functioning properly with your Dodge Cummins until the check engine light popped up, it has likely undergone some damage since you last used it.

It could also be that the scanner is too cheap to read the advanced codes that your car has stored. Such a scanner is useful for reading basic codes but gets less helpful the more complex the problem becomes.

If your scanner is new, and you purchase it to investigate the check engine light to no effect, it is likely incompatible with your Dodge Cummins. The scanners could also be a cheap imitation of popular brands that frequently fail to function like the more expensive alternative.

Solution

Buy a new code scanner or borrow one from a friend to rule out the possibility of damaging your scanner. If you suspect your scanner is failing to read the error code stored in your Dodge Cummins, try replacing it with a high-quality alternative. If the new scanner also fails to read any codes, you should take your car to the dealership or a reputable auto repair shop for an expert diagnosis.

2. An Electrical Malfunction

 Electrical shorts are rare but not impossible cause of a check engine light that displays without error codes. If your Dodge Cummins has suffered a short in the electrical system, the light could be powered accidentally, even though your engine components are working optimally. The short would explain the light turning on without any error codes present.

Solution

There is a simple test you can run to confirm or rule out a short as the cause of your Dodge Cummins check engine light but no code problem. Place your key in the ignition and turn it to the on position. Do this without starting your engine, and the light should go off after a few seconds. If the check engine light does not go away, your problem is not caused by an electrical short.

3. Blown Fuse

Blown fuses cause drivers all sorts of headaches. A check engine light without diagnostic codes is one of them. If your scanners fail to detect any codes, be sure to rule out a blown fuse before throwing out the scanner. Your powertrain module, electronic control module, and electronic control unit all rely on optimal fuse functioning to work effectively.

If you are suffering a blown fuse, these critical modules may malfunction due to a lack of sufficient power. This malfunction may trigger your check engine light to switch on, despite the lack of any diagnostic codes.

Solution

Drivers who suspect a blown fuse is causing their check engine light to switch on despite the lack of codes should consult their Dodge Cummins owner's user manual. The manual will help you figure out which fuses you should inspect. Once you locate the blown fuse, replace it with a new one.

Even though changing a blown fuse is an elementary DIY task, most drivers opt to take their vehicles to a dealership or a reputable auto repair for various reasons. Relying on the professionals may cost more, but it is guaranteed to save you the time, effort, and costly mistakes that may happen during a trial-and-error diagnosis and repair session.

4. Incorrect Use of Diagnostic Scanner

Though code scanners are simpler to use than most tools, it is still possible to get them wrong. If your check engine light is not yielding any codes, there is a slight possibility that you are using the code reader incorrectly.

Solution

Read your scanner's user manual to ensure you are using it as recommended. Follow the instructions to the letter and check whether your Dodge Cummings will yield an error code.

5. Malfunctioning Port

At times the port where you plug in the scanner may be a source of the problem. This port is usually found under the dashboard. If the port is loose or clogged by debris, you may encounter the check engine light but no code situation.

Solution

Inspect your port to determine if the connector is contaminated by dust or debris. If the connector is compromised, cleaning away the dirt and debris only takes a couple of seconds.

Troubleshooting Check Engine Without Any Stored Codes

Now that we have addressed the likely causes of the check engine light with no code getting to the bottom of the problem should be a walk in the park. Use the procedure detailed below:

• Begin by inspecting your code scanner. Ensure that you use a scanner compatible with your Dodge Cummins and can read many codes.
• If you are sure that your scanner is high-quality and compatible with your Dodge Cummins, you will need to check whether it is defective. The easiest way to do this is to test the scanner on a different car to see whether it is functioning correctly. You should invest in a new high-quality scanner if your scanner fails both of these tests.
• Inspect the port where you plug in the code scanner. Check for any signs of debris that may clog the connection. Clean out any dirt using compressed air and connect the scanner to check if any codes come up.
• Once you rule out all the causes above, checking for a blown fuse is next on your to-do list. Consult your owner's manual for the fuse layout. Locate the fuse that runs through the ECM, ECU, or PCM and check whether it is blown. If the fuse is blown, you can buy a new one for a couple of dollars. The check engine light should turn off once you replace the blown fuse.
• Inspecting your car for the cause of a short is a slightly complex task beyond any beginner DIYer's skillset. You will need to check for shorting signs, including a burning smell, flickering light, or visible scorch marks. If you locate a potential short, you must confirm the voltage using a multimeter. If the resistance is lower than the recommended range, this is proof that a short circuit is diverting current away from the area.
• If none of these fixes work for your Dodge Cummins, it is wise to visit the dealership or a reputable auto repair shop. Professional mechanics will combine their training with their extensive experience to ensure your get accurate diagnosis and effective repairs.