P0672 Duramax: Problems & Solutions

Why did the P0672 Duramax error code appear? When the diesel vehicle has issues with the cylinder 2 glow plug circuit, the vehicle system shows this P0672 code.

The glow plug is the primary part of the vehicle for the cold start. It produces heat at a high level so that the cold start is smoothly done. So, the cylinder 2 glow plug circuit is a significant diesel vehicle.

It is essential to know the reasons for P0672 code appearance, the symptoms, and the solution. Checking the sign, we can guess the reason. We have to go through certain checking and then solve the issue according to the cause.

In this article, you will get a detailing explanation of this P0672 error code. Why wait? Let’s go deep and know deeper.

Reasons, Symptoms & Solution to P0672 Duramax

Defective glow plugsHard start situation in the engine to the cold block
Burned, disconnected, corroded, damaged wires and connectorsEngine misses in cold weather The engine takes time to accelerate
Defective glow plug relay or glow plug timerProduction of white smoke The pre-hit light stays on for longer
Defective glow plug control moduleHard start in warm weather Failure of cold start in cold weather
PCM failureNo start condition appears Inadequate power situation

Since the glow plug is directly linked to the engine’s cold start in cold weather, the symptoms are apparent. You will get a more precise signal if the fault is extreme or at a higher level. When there is one or two fault or minor fault in the glow plug circuit, minimal signs arrive. Sometimes, you will only get the check engine light signal. A vehicle can perform a cold start with one or minor issue with the glow plug.

Now let’s find the solution to each specific cause.

Defect in Glow Plug

If the glow plug is entirely faulty, you will get a slow start in your vehicle at first. Then you will face a complete failure in starting the car. Even if the vehicle starts, it creates rough idle action and lots of white smoke till the engine warms. It will make a hard start if one glow plug is faulty in a four-cylinder vehicle. The car will send 04 Duramax P0672 error code.


First, check the glow plug. In reviewing the glow plug, you have to connect a 12-volt test light into the battery’s positive terminal. Now disconnect the wires from the glow plugs and connect the probe of the test light and the terminal of the glow plug by touching. Now the light should be on. If not, the glow plug is terrible for sure.

If you find the glow plug damaged or faulty, you have to replace it with the help of an expert.

Issues with Wiring or Connectors

Corrosion in wiring creates high electrical resistance, dropping the voltage. Then the amount of flowing current will fall. So, the engine will miss or skip in cold weather. The cold start will be hard. You will find the 2004 Duramax P0672 signal.


If the wiring or connectors are shorted or burned or disconnected, or corroded, first check the connections to ensure that all links are tightly fit. If not, reconnect the wiring and loosened connectors.

Then you have to run the multimeter test. There is two multimeter test lead. Connect one piece of information to the engine’s ground near the glow plug. Then connect the other lead to the terminal, situated at the top part of the glow plug. Now read the result from the multimeter display. If you find the resistance less than 6Ω, the connections are good. If it is more, you have to call an expert and replace corroded or damaged wires or wiring harnesses.

Defect in Glow Plug Timer or Relay

The glow plug relay controls the switch on and off the current flow for the glow plugs. A control unit of glow plug runs it. This control unit monitors the current flow. It provides a higher current as the circuit needs to start the engine. If it is faulty, the system will show the 2009 Duramax P0672 code.

Also Read: 4 Reasons Behind P1093 Duramax Error Code And Their Solutions

If the problem is with the glow plug timer or Relay, then the 2012 Duramax P0672 arrives, and you will find that the system of your vehicle is showing the check engine light during you start your car. You will also find the presence of white smoke before the engine is warm.


To check the glow plug relay, turn the multimeter on and then set it at resistance mode or Ω mode. Now, attach one lead of the multimeter to the engine’s ground and connect another lead to the power supply terminal. Now check the multimeter display reading. If it is 6Ω or less, then it is correct. Otherwise, you have to replace the glow plug relay.

Defect in Glow Plug Control Module

When the glow plug control module is defective, you will see white smoke coming out, which can cause the diesel to leak. You will find the vehicle engine to start hard. It will fail to perform the cold start, and even it will be hard to start in warm weather. The system will automatically show the 05 Duramax P0672 code when these problems begin.


When you understand that the problem can be with the control module of the glow plug, check the glow plugs first. When you find that the glow plugs are okay, check the battery voltage to the control module. If the voltage drop continues to a half volt, it is sure to replace the glow plug control module.

Failure in PCM

PCM works effectively to keep the flow of the cold start function of the engine. When you perform the engine’s cold start, PCM turns the light that signals for ‘wait to start for 3 to 5 seconds; it allows the glow plug to reach the engine at sufficient cylinder temperature to become easy to cold start. When the glow plug light is off, the PCM can keep it energized for a long time and reduce smoke. It improves the cold driveability efficiently.

When PCM on the glow plug system is faulty, starting for the inadequate temperature status will take time. The vehicle will show a 07 Duramax P0672 error code.


If PCM is found faulty, they are not like alternators or pumps. PCM is a standard system function. There are no mechanical parts in PCM. They were so, remanufacturing the PCM means-testing, isolating, and repairing the faults in the computer. According to the instruction in the manual, you can do it or get help from an expert. Resetting the computer can solve the issue altogether. PCM problems are rare. P0672 Chevy Duramax code shows the case with PCM.

A Helpful Tutorial You May Need!

Frequently Asked Questions (FAQs)

What is code P0672 mean?

P0672 error code indicates issues with cylinder 2 glow plug circuit. The glow plug circuit performs the engine’s heating process to a cold start in cold weather. If the P0672 LML Duramax code appears, the glowing course is faulty. There are specific reasons for the glow plug faults. First, find the causes and then solve the issues accordingly.

How do I fix code P0672?

There are specific steps to troubleshoot the P0672 Chevy Duramax error code. The first and most famous step is to validate the code using a code scanner. Then reset the code for road testing. After road testing of the vehicle, check if the code reappears. If it appears, then check the wiring and connectors. Thus one-by-one check every part of the glow plug circuit.


P0672 Duramax code is linked to the glow plug circuit among various error codes. It is an essential part of the engine system to keep the vehicle active even in colder weather. If there are any issues with the glow plug circuit, it won’t be comforting to run the engine even in warm weather. So, specific steps should be taken as soon as you see the signal for this error code.

This code can appear for minor issues even when the vehicle is running well. So, you can take time to reach the expert mechanics and find the problem. Solving the problems with glow plug soon is a wise act.

You Can Also Read:

D Conroy

Meet our senior writer and content manager of Automasterx. He has worked in several mechanical garages and mastered different vehicle diagnoses and parts repair. He never stops until finding out the ultimate solutions for any vehicle fault code. However, ensuring the only solid solutions for each vehicle malfunction is his core part of the duty, alongside analyzing fault codes and signals.

Similar Posts