P0676 code — how to fix error fast | REREV (2024)

For a driver of a diesel-powered car, getting the code P0676 is among the worst possible scenarios after using an OBD2 scanner. Most drivers have issues figuring out the P0676 code meaning and having so many possible reasons behind the code doesn’t help.

What could help, however, is if you had a complete guide on potential causes of the P0676 code and all the possible ways of fixing the code. We’ll tell you exactly what you need to know in this guide along with the diagnostic methods to find the reason behind the code based on all possible reasons.

Why you can trust REREV’s OBD2 code advice: Our automotive expert researchers with experienced mechanics undertakes a thorough research methodology to deliver precise insights on OBD codes. Find out more about OBD2 codes research process..

What does the P0676 code mean?

The P0676 code is a diagnostic trouble code that indicates a fault in the glow plug circuit in cylinder 6 of a diesel engine. The glow plugs are responsible for heating the air in the combustion chamber during cold starts. This makes it easier for the engine to start and run smoothly. The code is crucial because it can cause serious damage to your engine if left untreated.

If you don’t deal with this code right away, it could lead to serious problems including engine misfires, reduced performance, and even problems starting the car.

What causes the P0676 code?

There are various possible reasons behind the code P0676 and they range from faulty glow plugs to electrical issues and other related problems. If you want to solve the mystery of what caused the code in the first place, you’ll need to know about all of them:

Faulty glow plug

A faulty glow plug is the most common cause of the P0676 code. Over time, the glow plug can wear out or fail, preventing it from heating the air in the combustion chamber. Symptoms of a faulty glow plug include difficulty starting the engine, misfires, and a decrease in fuel efficiency.

Wiring issues

Wiring issues can also cause the P0676 code. Corrosion, damage, or a short circuit in the wiring can prevent the glow plug from receiving power. Symptoms of wiring issues include a rough idle, stalling, and poor performance.

Failed glow plug control module

The glow plug control module is responsible for sending power to the glow plugs. If the control module fails, the glow plugs won’t receive power, and the P0676 code will appear. Symptoms of a failed control module include difficulty starting the engine, misfires, and a decrease in fuel efficiency.

Which car models does the P0676 code affect the most?

While most cars with six-cylinder or eight-cylinder diesel engines are exposed to the code, there are some vehicles that are more prone to it than others. These include the following models:

  • Chevrolet Silverado: Drivers of the Chevy Silverado with a 3.0-liter turbo-diesel Duramax engine have reported numerous problems with the engine that are most likely related to glow plugs that trigger the P0676 code.
  • Ford F-250 Super Duty: The full-size pickup truck F-250 with a Powerstroke engine is also said to have issues with glow plugs that could lead to the code P0676 being displayed on the scanner.
  • Jeep Grand Cherokee; The Grand Cherokee with a 3.0-liter diesel engine is also affected by the code P0676 and could often display it in case of a faulty glow plug control module.

How to diagnose the P0676 code

It’s not enough to simply read the code to diagnose the issue, as you could have seen from our list of the possible reasons behind the code. It takes much more to properly fix the issue at hand, and that means you’ll need to dig deeper into the matter. We’ll help you on this path by giving you an overview of all the testing methods you may use:

Using an OBD2 code

The most common way to diagnose the P0676 code is by using an OBD-II scan tool. This tool can read and interpret the diagnostic trouble code, providing information on which component or system is causing the issue.

Checking the glow plug

Testing the glow plugs individually using a multimeter can help determine if any of them are faulty and need to be replaced.

Checking the glow plug voltage

Measuring the voltage across the glow plug circuit can help identify any issues with wiring or connectors that may be causing a low voltage supply to the glow plugs.

Using a scope

Using an oscilloscope to monitor the waveform of the voltage supply to the glow plugs can provide more detailed information on any irregularities or abnormalities in the circuit.

How to fix the P0676 code

The steps to fix the P0676 code will depend on the cause of the code. Here are the potential fixes for each cause:

Replace a faulty glow plug

If the glow plug is faulty, it will need to be replaced. The cost of a glow plug varies depending on the make and model of your vehicle. Generally, you can expect to pay between $50 and $150 for a new glow plug.

Repair wiring issues

If the wiring is damaged, corroded, or has a short circuit, it will need to be repaired or replaced. The cost of wiring repairs varies depending on the extent of the damage and the make and model of your vehicle.

Fix the failed glow plug control module

If the glow plug control module is faulty, it will need to be replaced. The cost of a control module varies depending on the make and model of your vehicle. Generally, you can expect to pay between $100 and $300 for a new module.

How to prevent the P0676 code

Preventing the P0676 code from appearing requires proper maintenance of your vehicle. Here are some preventative measures you can take:

  • Regular maintenance including oil changes and filter replacement
  • Fule system cleanings
  • Checking the glow plugs during every other service

If you’re not comfortable diagnosing or fixing the P0676 code yourself, seek professional help. A qualified mechanic can diagnose and fix the issue quickly and efficiently. This will save you time and money in the long run.

Our take

The P0676 code is a very troubling one since it can lead to a power loss while driving or even the engine stalling. These are all serious issues that are best prevented by making use of proper steps to diagnose and fix the culprit behind the code.

We hope that this guide will at least help you find out what the culprit is and fix the code before it can lead to any engine-related damage.

What are the symptoms of the P0676 code?

Some of the common symptoms of the P0676 code include difficulty starting the engine, rough engine idle, reduced engine power, and a decrease in fuel efficiency.

Can I drive my car with the P0676 code?

It is generally not recommended to drive a car with the P0676 code, as it can lead to further damage to the engine if left untreated.

How is the P0676 code diagnosed?

The P0676 code can be diagnosed using an OBD-II scan tool, visual inspection, testing of individual glow plugs, and measuring the voltage across the glow plug circuit.

P0676 code — how to fix error fast | REREV (2024)


What does cylinder 7 glow plug circuit open mean? ›

OBD-II Code Hard or no start in cold weather is defined as a Cylinder 7 Glow Plug Circuit/Open. The Glow Plug is used on diesel engines to preheat the cylinder before the engine is started. If the engine control module (PCM) detects the glow plug for cylinder seven is not operating properly, the PCM will set code P0677 ...

How to test glow plug control module? ›

If your glow plugs are all working correctly, move onto your glow plug control module. Start by checking the battery voltage to the glow plug control module, a voltage drop of over a half volt (or more) means your control module should be replaced.

What does cylinder 4 glow plug circuit open mean? ›

DTC P0674 means “Cylinder 4 Glow Plug Circuit/Open.” It's logged when the PCM detects that the glow plug circuit in cylinder 4 has a malfunction. The common causes of this error code include a faulty glow plug (cylinder 4), a bad glow plug module, and circuit issues.

What happens when a glow plug relay fails? ›

Problems Starting the Engine

Engine performance issues are at the heart of glow plug- and glow plug timer-related problems. When the glow plugs can't generate enough heat and power to the engine, or when the timer relay isn't working properly, it will have a difficult time starting smoothly, or it may not start at all.

What causes glow plugs to break? ›

Common reasons why glow plugs fail include:

Excessive carbon build up in your pre chambers. Folds and dents on the rod of the glow plug. Snapped or damaged tip of the glow plug. Excessive heat reaching the glow plug.

How do I know which glow plug is bad? ›

Any glow plugs that does not light the test light is bad. Alternate methods – Use an ohmmeter – (Again, disconnect all wires from each glow plug to prevent parallel paths.) Measure resistance between ground the terminal of each glow plug. Any glow plug that indicates infinity or more than a few ohms is bad.

How much does a glow plug circuit cost? ›

The average cost for a Glow Plug Control Module Replacement is between $314 and $336. Labor costs are estimated between $62 and $78 while parts are priced between $253 and $258. This range does not include taxes and fees, and does not factor in your unique location. Related repairs may also be needed.

Can you drive with a bad glow plug control module? ›

You can drive with a bad glow plug if you have to. But the drive should be short and should take you to the mechanic's shop. Driving on a faulty glow plug will result in continued poor performance. Eventually, your engine will misfire.

What are the symptoms of glow plug control module? ›

Possible symptoms of a faulty glow plug control unit or glow plug relay include: glow plugs not receiving power, glow plugs not staying on or the glow plug relay clicking rapidly.

Will a bad glow plug module cause no start? ›

Without the Glow Plugs working the truck can develop a Cylinder Misfire (Dead Hole) and lose power. Eventually it will not start as the temperature gets colder in the winter.

What happens when glow plugs start to fail? ›

Glow plugs help to provide the additional heat in the combustion chamber. If the required temperature is not reached due to faulty glow plugs, the engine's performance will be weakened, and it will have to work extra hard to meet the demands of the road. The vehicle's fuel efficiency will be negatively affected.

What does cylinder glow plug circuit open mean? ›

DTC P0673 stands for “Cylinder 3 Glow Plug Circuit Open” This code is logged when the PCM detects that the glow plug is unable to heat up. It is commonly caused by malfunctioning glow plugs, glow plug control plug module failure, and damaged wiring connectors.

What does glow plug circuit a mean? ›

P0380: Glow plug/Heater, circuit A - malfunction (2.0 HDi engine) This fault code does not light a lamp on the dashboard. It indicates a problem in the preheating circuit. This generic fault code does not specify the exact cause of the problem. The probable cause is a malfunction of the glow plugs themselves.

What does a relay do for glow plugs? ›

The glow plug control unit uses a glow plug relay to switch the current for the glow plugs on and off. The more glow plugs monitored by a control unit, the higher the current the circuit will need. To reduce the current needed, glow plugs are often distributed across two circuits, with two glow plug relays.

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