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

Our certified mechanics come to you · 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 1-800-701-6230.

P0671
trouble codes
Check Engine Light

No more waiting rooms! Our mechanics will come to you to diagnose and fix the P0671 code.

SCHEDULE P0671 DIAGNOSTIC
Get a $20 credit for the follow-up repair

Recent Check Engine Light is on Inspection reviews

Excellent Rating

(6,144)

Rating Summary
5,685
221
51
35
152
5,685
221
51
35
152

Chris

11 years of experience
13 reviews
Chris
11 years of experience
Ford F-150 - Check Engine Light is on - North Salt Lake, Utah
We were having problems with our check engine light, and Chris was exceptionally thorough until he found the problem and could help resolve the situation. We appreciate having someone who cares enough to get the job done right, not just done. We will definitely use Chris' services in the future. Thanks Chris.

Leng

21 years of experience
2 reviews
Leng
21 years of experience
Mazda MPV - Check Engine Light is on - Seattle, Washington
Leng arrived on time and explained the issue that my van is having. I will make a follow up appointment for the fix. Friendly, easy to talk to, and professional - thank you very much!

Okela

13 years of experience
11 reviews
Okela
13 years of experience
Land Rover LR4 - Check Engine Light is on - Brooklyn, New York
Okela was incredible! He is super thorough and took time to walk us through the issues with our LR4. Couldn’t recommend more! Thank you Okela!!

Robert

37 years of experience
188 reviews
Robert
37 years of experience
Land Rover LR2 - Check Engine Light is on - Atlanta, Georgia
Robert arrived on time. Did a diagnostic check quickly. He was friendly, and gave great service. He knows how to work on a Land Rover.


More related articles

Related questions

I have a 2012 cc with a p0016 code no start. chain is tight and all turns freely when turned by hand

Code P0016 broadly means that the PCM has detected that the Crankshaft and Camshaft are out of sync. If they are out of sync beyond a specific, threshold number of degrees, the car simply won't start. The cause of that...

Engine light blinking and the oil light come on. Accelerates slow but when you get to about 30 mph it smooth out. Then when you slow down it start shake.

For the cylinder that has excessive oil in it, the oil is either coming in for the piston rings being worn or the valve guide is leaking on the intake valve causing the engine to consume the oil. If the...

Engine noise, RPM fluctuation, ABS, 4x4 warning on

Hello. It sounds like you have a problem with the DME (digital motor electronics) and the ECU (engine control unit). It would not be a mistake to have these two things replaced. It is an expensive repair but I’m confident...

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 (855) 347-2779 · hi@yourmechanic.com