P0676 OBD-II Trouble Code: Cylinder 6 Glow Plug Circuit (2024)

P0676 OBD-II Trouble Code: Cylinder 6 Glow Plug Circuit (1)

P0676 Code Definition

The P0676 code is a generic powertrain code related to issues with a computer output circuit. In this case, it means that an issue has been noted with the glow plug circuit in cylinder 6 of a vehicle’s engine.

Codes related to the P0676 include:

  • P0670: Glow Plug Module Control Circuit
  • P0671: Cylinder 1 Glow Plug Circuit
  • P0672: Cylinder 2 Glow Plug Circuit
  • P0673: Cylinder 3 Glow Plug Circuit
  • P0674: Cylinder 4 Glow Plug Circuit
  • P0675: Cylinder 5 Glow Plug Circuit
  • P0677: Cylinder 7 Glow Plug Circuit
  • P0678: Cylinder 8 Glow Plug Circuit
  • P0679: Cylinder 9 Glow Plug Circuit
  • P0680: Cylinder 10 Glow Plug Circuit
  • P0681: Cylinder 11 Glow Plug Circuit
  • P0682: Cylinder 12 Glow Plug Circuit

What the P0676 Code Means

Used in diesel engines to heat a cylinder head when starting up a cold engine, the glow plug is an important part of cold weather start-up. Each cylinder of the engine has a glow plug to heat the cylinder head. A glow plug will typically last 100,000 miles, but can fail before that approximate mileage. The diesel engine uses the high level of heat through compression, which quickly ignites the fuel.

When a P0676 trouble code is stored, the system reference voltage allowed by the vehicle’s engine control module (ECM) has exceeded 10% of preset variance parameters in cylinder 6.

The glow plug is installed in the cylinder head as close as possible to the cylinders combustion point. Using oil and transmission sensors, the ECM will determine if the glow plug is needed for ignition and grounds the glow plug timer module, which grounds the glow plug relay. This is usually used on a cold start. Typically, a P0676 code means the glow plug for cylinder 6 has failed to heat up properly and could be damaged.

What Causes the P0676 Code?

Several problems may cause a P0676 code including:

  • Damaged or defective glow plug in cylinder 6
  • Damaged or defective glow plug module or timer
  • Damaged or defective glow plug relay
  • Possible blown fuse(s)
  • Damaged, defective, corroded or loose wiring, harnesses, and related connectors in the glow plug circuit for cylinder 6

What are the Symptoms of the P0676 Code?

Symptoms of a P0676 code may include:

  • An illuminated check engine or warning light
  • Glow plug indicator light may not illuminate or illuminate longer than normal
  • Vehicle may not start up as quickly as normal
  • Vehicle may not start at all in cold weather
  • Unusual amounts of white smoke when the vehicle starts
  • A possible loss in overall vehicle power
  • Abnormal, loud noise from the engine
  • The engine may misfire

How Does a Mechanic Diagnose the P0676 Code?

A mechanic may use several methods to diagnose a P0676 trouble code, including:

  • Utilize an OBD-II scanner to check for a stored P0676 trouble code

  • Visually inspect wiring, harnesses, and connectors related to the glow plug circuit for damage

  • Test the glow plug after disconnecting it from cylinder 6 and check ground and resistance

  • Check if glow plug will “warm up” with battery voltage or test with digital volt/ohmmeter - check plug color

  • Test all system fuses to ensure they are in working order with the glow plug heater activated

  • Test glow plug timer, relay, or module

Common Mistakes when Diagnosing the P0676 Code

If blown fuses are located, there may be an underlying problem beyond what a P0676 code holds, so it is always recommended to repair stored codes in the order in which they appear. Often, glow plug timers and relays are replaced before wiring and the glow plug itself is tested, which can lead to misdiagnosis and unnecessary repairs.

How Serious is the P0676 Code?

Because a vehicle’s safe driving operation may be impacted due to faults that store a P0676 code, this code is considered a potentially serious code. When this code appears, it is recommended to immediately take your vehicle to your local service center or mechanic for repair and diagnosis.

What Repairs can Fix the P0676 Code?

Several repairs can fix a P0676 trouble code and include:

  • Repair or replace any damaged, corroded, or loose wiring, connectors, and harnesses
  • Replace any blown fuses and repair any shorts
  • Replace damaged or broken glow plug for cylinder 6
  • Replace the glow plug relay for cylinder 6
  • Repair or replace any bent or damaged pins in electrical connectors
  • Clear all codes, test-drive the vehicle, and rescan to see if any codes reappear

Often, additional glow plug circuit codes will accompany a P0676, so it is recommended to do a full diagnosis and note all trouble codes that may be stored to fully repair the issue. Ensure that codes are handled in the order they appear on the scanner.

Need Help with a P0676 Code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.

Check Engine Lighttrouble codesP0676
P0676 OBD-II Trouble Code: Cylinder 6 Glow Plug Circuit (2024)


P0676 OBD-II Trouble Code: Cylinder 6 Glow Plug Circuit? ›

A faulty glow plug, wiring issues, and a malfunctioning glow plug control module can cause this trouble code to appear. If left unresolved, a P0676 can cause your vehicle to exhibit symptoms like hard starting, an illuminated preheating light, and a no-start condition under cold temperatures.

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 is OBD code for glow plug? ›

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.

What is a glow plug circuit? ›

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.

Is it safe to drive with a faulty glow plug? ›

No, it is not safe to drive with a faulty glow plug. An improper combustion chamber temperature will lead to inadequate fuel ignition, resulting in the misfiring or rough running of your engine. This could potentially put you in danger if you are driving at high speeds or in hazardous conditions.

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.

What is the code P0676 on glow plugs? ›

What Does the P0676 Code Mean? Diagnostic trouble code (DTC) P0676 stands for “Cylinder #6 Glow Plug Circuit/Open.” Some diesel engines use glow plugs to warm up the combustion chamber before starting the engine.

What are the symptoms of glow plug failure? ›

In this article, we look at six common signs that indicate glow plugs could be faulty or damaged.
  • Something's Wrong: The Engine Warning Light. The engine warning light on the dashboard is typically the initial sign of a problem. ...
  • Hard Starting. ...
  • Engine Misfiring. ...
  • Rough Idling. ...
  • Decreased Fuel Effeciency. ...
  • White Smoke. ...
  • Black Smoke.

Are glow plugs expensive to replace? ›

Glow plugs aren't too expensive, but it depends on the make and model of your car. Costs can also vary between glow plug brands. Halfords stocks a huge range of glow plugs online. Just use our car part finder tool to find the right glow plug for your car.

Are glow plugs easy to replace? ›

Cars may have gotten more complex over the years, yet changing your vehicle's glow plugs is, in most cases, still a job that you can handle yourself. However, before jumping into the job, you want to make sure you have a Manual Torque Wrench, and the right glow plugs for your vehicle.

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 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 does cylinder 5 glow plug circuit open mean? ›

What Does the P0675 Code Mean? Diagnostic trouble code (DTC) P0675 stands for “Cylinder 5 Glow Plug Circuit/Open.” This code is logged when the powertrain control module (PCM) detects that the glow plug for cylinder #5 is not working like it normally would.

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 ...

What can cause glow plug issues? ›

Common reasons why glow plugs fail include:

Folds and dents on the rod of the glow plug. Snapped or damaged tip of the glow plug. Excessive heat reaching the glow plug. High voltages reaching the glow plug.

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