P0671 OBD-II Trouble Code: Cylinder 1 Glow Plug Circuit

Our certified mechanics come to you · 12-month, 12,000-mile warranty

SCHEDULE P0671 DIAGNOSTIC Get a fair and transparent estimate upfront
Red-stars EXCELLENT RATING ON

Cost of diagnosing the P0671 code

P0671 is a diagnostic trouble code (DTC) for "Cylinder 1 Glow Plug Circuit". This can happen for multiple reasons and a mechanic needs to diagnose the specific cause for this code to be triggered in your situation. Our certified mobile mechanics can come to your home or office to perform the Check Engine Light diagnostic. Once we are able to diagnose the problem, you will be provided with an upfront quote for the recommended fix and receive $20.00 off as a credit towards the repair. All our repairs are backed by our 12-month / 12,000-mile warranty.

Cars Estimate Credit towards follow-up repair Earliest Availability
Ford$20.00
Toyota$20.00
BMW$20.00
SCHEDULE P0671 DIAGNOSTIC Get a fair and transparent estimate upfront

P0671 code definition

The P0671 code indicates that the PCM has detected an abnormal voltage reading from the glow plug circuit in cylinder 1.

What the P0671 code means

Diesel engines require glow plugs to heat cylinders before and during the ignition process. Each cylinder has a glow plug, which uses battery voltage to heat up. The PCM controls the activation of the glow plug circuit, and monitors the activity with voltage readings. If the voltage reading does not match the manufacturer’s specifications, it is likely that the glow plug is not working properly to heat the engine. In this case, the PCM will store the P0671 code.

What causes the P0671 code?

There are many things that can cause the P0671 code. These include:

  • Faulty glow plug
  • Faulty glow plug relay
  • Faulty glow plug timer
  • Faulty electrical components within the glow plug circuit
  • Blown fuses, which could indicate a larger issue

What are the symptoms of the P0671 code?

Most of the time, the vehicle’s owner will notice that the vehicle is taking longer to start, and that the glow plug indicator light never deactivates, or stays on for longer than normal. White smoke may be observed upon start-up; the engine may be considerably louder than normal during start-up; the engine may misfire; and the Check Engine lamp will be illuminated.

How does a mechanic diagnose the P0671 code?

After an OBD-II scanner detects the P0671 code, a technician should begin with a visual inspection of the electrical components, repairing or replacing any damaged components as necessary. After this, and any other repair process, the PCM should be cleared, and the system should be retested, to find out if the repair solved the issue.

If the electrical components were not to blame, the mechanic will begin checking the glow plug connector, the glow plug itself, and fuses, for proper function. Activating the glow plug heater after checking each of these repairs will show the mechanic if there is a short in the circuitry, or if the parts themselves were to blame.

Common mistakes when diagnosing the P0671 code

While glow plugs themselves, and the electrical components within the glow plug circuit, are often to blame for the P0671 code, many technicians report that glow plug timers and relays are frequently replaced without checking the electrical components and glow plugs.

How serious is the P0671 code?

The P0671 code represents a serious issue that affects the drivability of the vehicle. If left unrepaired, the vehicle may not start properly, or at all, in the future.

What repairs can fix the P0671 code?

There are many ways that a technician can address a P0671 code detection. They include:

  • Replacing faulty glow plug
  • Replacing faulty glow plug relay
  • Replacing faulty glow plug timer
  • Replacing or repairing faulty electrical components within the glow plug circuit
  • Replacing blown fuses

Additional comments for consideration regarding the P0671 code

When repairing any issue related to the glow plugs, safety is very important. When activated, glow plugs become extremely hot. Technicians should exercise caution when testing glow plugs for proper functionality.

Need help with a P0671 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 1-800-701-6220.

P0671
trouble codes
Check Engine Light

Fast and easy Check Engine Light is on Inspection service at your home or office.

SCHEDULE P0671 DIAGNOSTIC
Get a fair and transparent estimate upfront

Recent Check Engine Light is on Inspection reviews

Excellent Rating


YourMechanic Check Engine Light is on Inspection Service

Average Rating

4.8/5

Number of Reviews

4,829

Rating Summary
4,442
187
48
28
124
4,442
187
48
28
124

Walter

44 years of experience
64 reviews
Walter
44 years of experience
Jeep Grand Cherokee - Check Engine Light is on - Tulsa, Oklahoma
Went above and beyond my expectations, as i was very nervous about this type of service! But to my surprise, I am absolutely satisfied with the service ! Would recommend 100X to all i know! Thanks for the care and information and time you put in to my qoute and truck@

Keith

16 years of experience
279 reviews
Keith
16 years of experience
BMW 535i xDrive - Check Engine Light is on - Kissimmee, Florida
Very personable, knowledgeable person, who provided information on my car that I was not aware of. The overall experience was great and I would definitely refer this company to my family and friends.

Luis

13 years of experience
20 reviews
Luis
13 years of experience
Audi A3 - Check Engine Light is on - Van Nuys, California
Luis was awesome. Very knowledgeable and a down to earth person. Would highly recommend and plan on using him in the future for any repair that I need!

Joel

19 years of experience
742 reviews
Joel
19 years of experience
Acura RL - Check Engine Light is on - Jacksonville, Florida
very knowledgeable and precise. able to fix electrical issues in my car. Right on time for the appointment.

More related articles

Related questions

Engine rattling, shaking and loss of power

The VANOS unit or solenoid can cause a rattling sound from the engine. The VANOS is a camshaft timing system which runs off of engine oil pressure. If the oil is the wrong viscosity or the system has a buildup...

I HAVE A 2002 ALERO OLDSMOBILE IT HAVE 3 CODES DO U KNO WHAT IT CAN BE IF I TELL U THE CODES

Misfire codes can be caused by a range of failures. Spark Plugs, Coils, Injectors, Manifold gaskets could all be suspect. When the check engine light is on and the car has stored codes, your first reaction is to replace the...

Bad O2 sensor

I would ask for help from one of the mechanics at YourMechanic. They can come to your location and replace the faulty O2 sensor for you.

How can we help?

Our service team is available 7 days a week, Monday - Friday from 6 AM to 5 PM PST, Saturday - Sunday 7 AM - 4 PM PST.

1-800-701-6230 · hi@yourmechanic.com