OBD-II Code
P0671
Severity
Not yet reviewed
Nobody on our side has assessed this code yet, so we are not going to guess at how serious it is.
Can you drive it
We cannot say
Treat it as unknown until a shop reads it with live data. If the check-engine light is FLASHING, stop driving as soon as it is safe to — that means an active misfire, whatever the code.
Indicative cost (USD)
$80–$1,800
From this code's diagnostic notes. Varies by vehicle, diagnosis, parts, and local labor. This is not a repair quote.
P0671 is a per-cylinder glow plug circuit fault for cylinder 1, indicating the module detected an open, short, or out-of-range resistance on that specific glow plug branch.
How a shop works this
Work from evidence to part, not the other way round. A code names a circuit or a symptom; it does not name the part that failed.
Note every code that is set, not just this one.
Codes that appear together usually narrow the cause faster than any one of them read alone.
Read the freeze frame — the conditions the fault was recorded under.
Cold or warm, idle or load, road speed and engine speed. A fault that only appears cold is a different fault from one that only appears under load, even with the same code on the scanner.
Confirm the fault is current rather than history.
Clear the code and see whether it returns under those same conditions. A code that does not come back may have been logged during a repair, a flat battery, or a bad connection that has since been disturbed.
Then follow the diagnostic notes further down this page, in the order they are written.
They are written in the order a shop works this code, cheapest checks first. Where they name a component, inspect its wiring and connector before replacing it.
If the code comes back after a repair, the underlying fault is still there. That is the point to bring in a scanner with live data and freeze-frame, or a shop that has one.
Common symptoms
- Check engine light
Read the full diagnostic procedureP0671 is a per-cylinder glow plug circuit fault for cylinder 1, indicating the module detected an open, short, or out-of-range resistance on that spe…
P0671 is a per-cylinder glow plug circuit fault for cylinder 1, indicating the module detected an open, short, or out-of-range resistance on that specific glow plug branch.
Cheapest first
- pull the valve cover (or remove the intake on top-of-head designs) and ohm-check the glow plug at the plug itself with the harness disconnected; a healthy glow plug reads roughly 0.5 to 2.0 ohms cold (varies by manufacturer, but values above 3 ohms or open circuit are bad, and values below 0.3 ohms indicate an internal short).
- Wiggle-test the harness connector at the plug since the rubber boots harden and crack from underhood heat.
- Caveat: do not replace all glow plugs as a set on a P0671 unless your testing confirms multiple plugs are weak, because the labor on stuck or seized glow plugs (especially on 6.0L Powerstroke and Mercedes OM642) can balloon a $30 part into a $2,000 cylinder-head-off repair if a plug breaks off in the head.
Vehicle-specific patterns2003 to 2007 Ford 6.0L Powerstroke routinely seizes glow plugs in the head, and P0671 on cylinder 1 (front driver side) is often paired with a snappe…
- 2003to 2007 Ford 6.0L Powerstroke routinely seizes glow plugs in the head, and P0671 on cylinder 1 (front driver side) is often paired with a snapped plug tip when extraction is attempted; this is the job that turns into a head-out repair if the tip drops into the cylinder.
- 2007to 2013 Mercedes Sprinter and 2007 to 2009 Jeep Grand Cherokee with the OM642 3.0L V6 diesel are notorious for glow plug seizure and require Beru extractor kits.
- 2004to 2010 Chevy and GMC 6.6L Duramax LLY/LBZ/LMM trips P0671 when a single glow plug shorts internally or the pigtail fails at the connector boot.
- 2009to 2014 VW and Audi 2.0L TDI common-rail engines set P0671 from the dual-coil ceramic glow plugs failing one at a time.
Estimated repair$80 to $1,800.
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