Skip the auto shop - Our mechanics make house calls

P0680 OBD-II Trouble Code: Cylinder 10 Glow Plug Circuit

Check Engine Light

P0680 Code definition

The P0680 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 10 of your engine.

Codes related to the P0680 include:

What the P0680 code means

Used in diesel engines to heat a cylinder head when starting up a cold engine, the glow plug is an integral part of cold weather start-up in a diesel-powered vehicle. The diesel engine uses the high level of heat through compression, which then quickly ignites the fuel. 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 approximte mileage.

When a P0680 trouble code is stored, the system reference voltage allowed by the vehicle’s engine control module (ECM) has exceeded 10% of the allowed variance.

The glow plug is installed in the #10 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 P0680 code means the glow plug for cylinder 10 has failed to heat up and could be damaged or faulty.

What causes the P0680 code?

Several problems may cause a P0680 code including:

  • Damaged or defective glow plug in cylinder 10
  • Damaged or defective glow plug module or timer
  • Replace the glow plug relay
  • May have blown a fuse(s)
  • Damaged, defective, corroded or loose wiring, harnesses, and related connectors in the glow plug circuit for cylinder 10

What are the symptoms of the P0680 code?

Symptoms of a P0680 code may include:

  • An illuminated warning or check engine light
  • Vehicle may start up more slowly than normal
  • Vehicle may not start at all in cold weather
  • Glow plug indicator light may not illuminate or may illuminate longer than normal
  • There may be an unusual amount of white smoke when the vehicle starts
  • A possible loss in overall vehicle power
  • Abnormal, loud noise may be heard coming from the engine
  • The engine may misfire

How does a mechanic diagnose the P0680 code?

A mechanic may use several methods to diagnose a P0680 trouble code, including:

  • Utilize an OBD-II scanner to check for a stored P0680 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 10 and check ground and resistance

  • Check if glow plug for cylinder 10 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 glow plug timer, relay, or module

Common mistakes when diagnosing the P0680 code

If blown fuses are located, there may be an underlying problem beyond what a P0680 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 P0680 code?

Because a vehicle’s safe driving operation may be impacted due to faults that store a P0680 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 P0680 code?

Several repairs can fix a P0680 trouble code and include:

Additional comments for consideration regarding the P0680 code

Often, additional glow plug circuit codes will accompany a P0680, 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 P0680 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.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
Icon-warranty_badge-02

Skip the repair shop, our top-rated mechanics come to you.

At your home or office

Choose from 600+ repair, maintenance & diagnostic services. Our top-rated mechanics bring all parts & tools to your location.

Fair & transparent pricing

See labor & parts costs upfront, so you can book with confidence.

12-month, 12,000-mile warranty

Our services are backed by a 12-month, 12,000-mile warranty for your peace of mind.

Get A Quote

Need Help With Your Car?

Our certified mobile mechanics make house calls in over 2,000 U.S. cities. Fast, free online quotes for your car repair.

GET A QUOTE

More related articles

How to Transfer a Car Title in Idaho
In order to prove ownership of a car, you must have the title. However, when a car is sold, given away or inherited, the title needs...
Veteran and Military Driver Laws and Benefits in Idaho
The state of Idaho offers a number of benefits and perks for those Americans who have either served in an Armed Forces branch in the...
Auto Safety Tips
Driving is more than a way to get from point A to point B. Owning and driving a car can also be a highly enjoyable experience. Whether a person is driving...


Related questions

Q: My mpv gave a code Shift Solenoid Stuck On just replaced solenoid a and b still dont work . wont drive

Return the vehicle to the shop that replaced the shift solenoids and have them check again. Most reputable shops provide a brief warranty on their repairs. If the repair was made by you, double check all the electrical connectors, on...

Q: Trying to figure out why my truck want go over 10 MPH

If your vehicle is a newer vehicle with electronic throttle control the system will limit throttle opening when it detects a system failure. The computer will limit the throttle opening while the problem is present. You will need to scan...

Q: P2006 code is present in the computer.

Hi there. With having the code P2006 present, check the intake wiring to the runner control and see if there is a good connection. Also, the runners in the intake could be clogged and needs cleaned out. A leaking or...