P0671

Cylinder 1 Glow Plug Circuit/Open

Diesel glow plug / preheat Generic OBD-II High

What it means

P0671 is a diesel-engine code showing an open circuit in the glow plug for cylinder 1. Glow plugs preheat the cylinders so the engine fires easily when cold, so with this fault you will notice hard cold starts and rough running until the engine warms up. The engine still runs, but the cylinder 1 glow plug or its wiring needs attention.

High

Can I keep driving? The engine still runs, but on a diesel it may be hard to start and run rough when cold until the cylinder 1 glow plug circuit is repaired.

Real-world scan data

Seen in

1,626

scans in the past year

Found in

0.3%

of scans

0.5%

of scans that found faults

Appears alongside · share of P0671 scans

P0672in 34.8% of scans

P0673in 34.7% of scans

P0674in 25.5% of scans

Figures reflect only diagnostic scans recorded through our own apps and tools. Cars are typically scanned because a symptom or warning light prompted it, so these counts describe our scan records — not the incidence of faults in any model, and not the quality, reliability, or safety of any vehicle. No comparison between manufacturers or models is implied. All trademarks belong to their respective owners; no affiliation or endorsement is implied.

Common symptoms

What you'll notice

Hard starting, especially in cold weather
Check-engine (or glow plug) light on
Rough running and misfire-like shudder when the engine is cold
White or grey smoke from the exhaust on a cold start

Common causes

Most likely first

Failed glow plug on cylinder 1 (open element)Likely
Open or broken wiring between the glow plug module and cylinder 1Common
Corroded or loose connector at the glow plugCommon
Glow plug control module fault affecting the cylinder 1 outputLess often

How to diagnose & fix

Work through it in order

Read freeze-frame data and check for glow plug codes on other cylinders to narrow the fault.
Measure the resistance of the cylinder 1 glow plug — an open reading means the plug has failed.
Inspect the wiring and connector from the glow plug module to cylinder 1 for breaks or corrosion.
Replace the failed glow plug or repair the circuit, then clear and re-test on a cold start.

FAQ

Quick answers

Is it safe to drive with P0671?+

Yes once running, but cold starts get harder and the engine runs rough until warm, so repair it before winter.

Can I just clear P0671?+

It will return on the next cold start until the cylinder 1 glow plug or its circuit is fixed.

Read & clear P0671 yourself

Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.

▶ Get it on Google Play

✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX