P0673 Code Definition
The P0673 code is a generic powertrain code related to issues with a computer output circuit. In this case, it means that an issues has been noted with the glow plug circuit in cylinder 3 of your engine.
Codes related to the P0673 include:
- P0670: Glow Plug Module Control Circuit
- P0671: Cylinder 1 Glow Plug Circuit
- P0672: Cylinder 2 Glow Plug Circuit
- P0674: Cylinder 4 Glow Plug Circuit
- P0675: Cylinder 5 Glow Plug Circuit
- P0676: Cylinder 6 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 P0673 Code Means
A glow plug is a device utilized in diesel engines to heat a cylinder head when starting up a cold engine. The diesel engine uses the high level of heat through compression, which quickly ignites the fuel. Each cylinder of the engine has a glow plug to heat the cylinder head.
When a P0673 trouble code is stored, it means that the system reference voltage allowed by the vehicle’s engine control module (ECM) has exceeded 10% of preset variance parameters.
While a glow plug will typically last 100,000 miles, they can fail before that mileage. 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. Typically, a P0673 code means the glow plug has failed to heat up and could be damaged.
What Causes the P0673 Code?
Several problems may cause a P0673 code including:
- Damaged or defective glow plug in cylinder 3
- Damaged or defective glow plug module or timer
- Damaged or defective glow plug relay
- Blown fuse(s)
- Damaged, defective, corroded or loose wiring, harnesses, and related connectors n the glow plug circuit
What are the Symptoms of the P0673 Code?
Symptoms of a P0673 code may include:
- An illuminated warning or check engine light
- Vehicle may not start up as quickly as normal
- Vehicle may not start at all in cold weather
- Glow plug indicator light may not illuminate or illuminate longer than normal
- Additional white smoke when the vehicle starts
- Vehicle may have a loss in power
- Abnormal, loud noise from the engine
- The engine may misfire
How Does a Mechanic Diagnose the P0673 Code?
A mechanic may use several methods to diagnose a P0673 trouble code, including:
Test glow plug timer, relay, or module
Utilize an OBD-II scanner to check for a stored P0673 trouble code
Check if glow plug will “warm” with battery voltage or test with digital volt/ohmmeter
Test all system fuses to ensure they are in working order with the glow plug heater activated
Test the glow plug after disconnecting it from cylinder 3 and check ground and resistance
Visually inspect wiring, harnesses, and connectors related to the glow plug circuit for damage
Common Mistakes when Diagnosing the P0673 Code
If blown fuses are located, there may be an underlying problem beyond what a P0673 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 P0673 Code?
Because a vehicle’s safe driving operation may be impacted due to faults that store a P0673 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 P0673 Code?
Several repairs can fix a P0673 trouble code and include:
- Repair or replace any damaged, corroded, or loose wiring, connectors, and harnesses
- Replace damaged or broken glow plugfor cylinder 3
- Replace any blown fuses and repair any shorts
- Replace the glow plug relay
- 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 P0673, so it is recommended to do a full diagnosis and note all trouble codes that may be stored to fully repair the issue.
Need Help with a P0673 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 LightP0673trouble codesFAQs
Typically, a P0673 code means the glow plug has failed to heat up and could be damaged. Error Code P0673 means that there's a problem in the glow plug circuit, causing cylinder 3 glow plug to fail from heating up. This will require a complete and thorough inspection to locate the fault.
What are the symptoms of a cylinder 3 glow plug circuit open? ›
It is commonly caused by malfunctioning glow plugs, glow plug control plug module failure, and damaged wiring connectors. Common symptoms associated with this code include a lit check engine light, difficulty starting the vehicle, and a preheat light that doesn't go off.
Can you drive with a P0673 code? ›
How Serious Is the Code P0673? This issue is critical and can lead to damages in your car. Please clear it first, drive your car for a couple of days. If the issue reappears, Carly recommends to fix your car to resolve this issue.
What is a glow plug circuit fault? ›
If the engine starts to misfire, it is an indicator that the combustion process isn't working properly, which could involve a fault with the glow plug or fuel injection system. If, when idling, the engine starts to produce white smoke from the exhaust, it could indicate that the glow plugs have burned out.
What is OBD2 glow plug code? ›
"3" in the third character position in a DTC indicates that the ignition system or misfire is experiencing a malfunction. The last two characters "80" is DTC number. OBD2 Diagnostic Trouble Code P0380 means that GLow Plug /Heater Circuit has been detected.
What happens when cylinder 3 is misfiring? ›
Your vehicle jerks, stalls, or loses power.
Your 3 cylinder is misfiring, which means it isn't generating power the way that it should.
Can a car drive with 3 glow plugs? ›
Yes, on engines which use glow plugs they all come on at once provided they are functioning properly. They are only needed briefly while the engine & ambient air are cold.
Can you drive without glow plugs? ›
Sure. The glow plugs are only used to start the engine. They are out of play at any other time during operation. If it actually does start, no problem.
Can I drive with a glow plug problem? ›
Driving With a Bad Glow Plug
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.
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.
The average cost of replacing a diesel engine glow plugs is £170, with prices ranging from £125 to £250 with pressure sensing glow plugs costing more. These prices include the cost of replacing ALL glow plugs in a vehicle. Due to their small size, glow plugs that have seized in place are susceptible to breaking.
Can a faulty glow plug damage an engine? ›
In some cases, it may even cause white smoke to come out from the exhaust due to incomplete burning of the fuel. If left unchecked, glow plug failure can even cause further damage to other parts of the engine such as spark plugs or cylinders.
Can you replace glow plugs yourself? ›
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 are the symptoms of one bad glow plug? ›
A number of faults can cause the engine warning light to illuminate – below, we outline the clues which point to faulty glow plugs.
- Hard starting. A hard starting engine is the most common indicator of damaged glow plugs. ...
- Engine misfiring. ...
- Rough idling. ...
- Decreased fuel efficiency. ...
- White smoke. ...
- Black smoke.
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.
Can faulty glow plug damage engine? ›
In some cases, it may even cause white smoke to come out from the exhaust due to incomplete burning of the fuel. If left unchecked, glow plug failure can even cause further damage to other parts of the engine such as spark plugs or cylinders.
