What Codes Will This Page Cover?
There are multiple codes that this page will cover, all having to do with different cylinders’ glow plugs. Here is the list of code descriptions:
- P0671 Cylinder 1 Glow Plug Circuit/Open
- P0672 Cylinder 2 Glow Plug Circuit/Open
- P0673 Cylinder 3 Glow Plug Circuit/Open
- P0674 Cylinder 4 Glow Plug Circuit/Open
- P0675 Cylinder 5 Glow Plug Circuit/Open
- P0676 Cylinder 6 Glow Plug Circuit/Open
- P0677 Cylinder 7 Glow Plug Circuit/Open
- P0678 Cylinder 8 Glow Plug Circuit/Open
- P0679 Cylinder 9 Glow Plug Circuit/Open
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What Is the P0671 Code?
Symptoms
Causes
Seriousness
Can I Still Drive?
Diagnose
Difficulty of Inspecting
Get Additional Help
The definition of code P0671 is “Cylinder 1 Glow Plug Circuit/Open,” and every other code on this list simply changes which cylinder’s glow plug is reporting a problem. This code means that the powertrain control module (PCM) or engine control module (ECM) has detected an issue with your vehicle’s glow plug circuit, a part of the system that helps your diesel engine handle a cold start much more easily. While this generic powertrain code can be found in many OBD-II vehicles, you will only find it in diesel engines, as only diesel vehicles use the glow plug setup.
You might also be interested in P1391 – Glow Plug Circuit Low Input – Bank 1
More About Error Code P0671
Diesel engines use a different system to ignite their fuel mixture than typical gasoline engines. Diesel engines rely entirely on compression to cause their fuel to spontaneously ignite, rather than using ignition circuits to create the ignition source. Glow plugs are basically small heaters, much like the electric stove in your kitchen. The glow plugs receive power that creates intense heat, causing the metal to glow bright red; the heat is mostly released in the combustion chamber, allowing the air/fuel mixture to interact with the heat and combust the fuel more easily, especially at cold engine temperatures. If this code is active, the Cylinder 1 glow plug has experienced a problem with its circuit.
What Are the Symptoms of a P0671 Code?
Usually, if just one glow plug has a failure code, your symptoms will be minimal, as other plugs will usually step in to handle the slack. You’ll be more likely to see problems if you’re trying to start your vehicle during cold weather, especially under freezing conditions. The most common symptoms you’ll see if there are drivability symptoms include difficulty starting your engine, with the engine occasionally not starting if it’s cold enough outside. Lack of power with a cold engine until the engine heats up, or hesitation during acceleration, is also very common. If more cylinders have glow plug issues, these symptoms are also much more likely. Your check engine light will also often turn on, although this isn’t always true with this specific code.
What Are Some Causes of a P0671 Code?
The primary cause of this error code is issues with your sensors or wiring. This includes a faulty cylinder #1 glow plug, damaged wiring connector, electrical connection issue, or open or shorted glow plug circuit. Occasionally, there may be an issue within the rest of the glow plug system, like your glow plug timer module or a faulty glow plug relay. In rare situations, you may also see an issue with your glow plug control module or even your PCM or ECM, although these problems are exceedingly uncommon, especially if this is the only issue you’re dealing with.
How Serious Is the P0671 Code?
While the severity level is usually low if you only deal with one glow plug failure, this glow plug code is still fairly important to fix, especially if you’re experiencing freezing temperatures outside. While your vehicle may be able to start now, it’s still not ideal to have one cylinder that doesn’t start effectively when it’s cold outside, and it also means that if any of your other glow plug circuits start malfunctioning, you may be stranded. Fix the problem as soon as possible for the best results.
Can I Still Drive with a P0671 Code?
You’ll usually be able to drive if DTC P0671 is the only diagnostic trouble code you’re experiencing. This code doesn’t usually make it difficult to drive your vehicle. However, as previously indicated, you may have a much more difficult time starting your diesel engine, and the colder it is outside, the more of a difficult time you may have. Because this code makes it much more difficult to start your vehicle, you should avoid driving with the code active.
How Easy Is It to Diagnose a P0671 Code?
Diagnosing the P0671 code isn’t especially difficult, as far as error codes go, but it still requires a bit of knowledge and experience with the glow plug system to understand and fix the core problem. There are only a few common causes associated with the P0671 code, which means there are fewer problems you have to test for, but you’ll still need to check for them. If you’re uncomfortable diagnosing a problem in your engine by yourself, it’s best to talk to a certified mechanic.
How Difficult Is It to Inspect a P0671 Code?
Inspecting the P0671 code requires many of the same advanced tools that you would use to inspect other codes in your vehicle, such as a code scanner, a digital volt/ohmmeter (DVOM), and a reliable vehicle information source, which may include wiring diagrams, technical service bulletins, and vehicle service guides. If you’re not comfortable getting into the wiring behind some of the most important components in your vehicle, it’s a good idea to talk to a professional mechanic so you can get the repair steps you need more easily.
Need Additional Help with Your P0671 Code?
Many DIYers seek help with the P0671, P0672, P0672, P0673, P0674, P0675, P0676, P0677, P0678, or P0679 code because it’s such a critical part of your vehicle, and any issues associated with these codes can result in engine concerns.
First and foremost, you should find an auto repair shop in your area. A local auto repair shop will play a big part in helping you fix your problems without requiring you to go too far out of your way.
This code also frequently comes with additional codes, which you should usually fix before you fix this one. The OBD-II database will help you understand these codes and how to fix them.
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