OBD-II Code
P0675
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–$1,400
From this code's diagnostic notes. Varies by vehicle, diagnosis, parts, and local labor. This is not a repair quote.
$80 (single plug, easy access) to $1,400 (full set on the Powerstroke, including UVCH harness).
P0675 means the ECU detected a fault in the glow plug circuit feeding cylinder 4 specifically — open, short, or resistance out of spec, set by the Glow Plug Control Module during the glow cycle.
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 procedureP0675 means the ECU detected a fault in the glow plug circuit feeding cylinder 4 specifically — open, short, or resistance out of spec, set by the Gl…
P0675 means the ECU detected a fault in the glow plug circuit feeding cylinder 4 specifically — open, short, or resistance out of spec, set by the Glow Plug Control Module during the glow cycle.
The cheapest-first diagnostic ladder
- Pull the pigtail at cylinder 4 and ohm the plug — healthy 0.4-2.0 ohms cold (most diesels 0.6-1.2 ohms), 0 shorted, infinite open, 4+ weak.
- Confirm the GPCM is commanding the cyl 4 channel with the expected PWM duty (0-100% scaled to coolant temp) and glow-on time (5-30 sec below 60F coolant).
- Clamp an amp probe on the feed wire and watch for 7-20A inrush falling to 5-15A; flat 0A with command ON is an open circuit, sustained 20A+ is a short. Test resistance INDIVIDUALLY at the glow plug terminal — pulling a shorted plug measures 0 ohms; an open plug measures infinite; a marginally weak plug measures 4+ ohms cold and is the most common cold-start hard-start root cause. Replace as a set on diesel engines — mixed-age plugs cause progressive failure.
Vehicle-specific patterns2003-2007 Ford 6.0L Powerstroke V8 throws P0675 from cylinder 4 (passenger bank, second from front) when the FICM is borderline — cylinder 4 is one o…
- 2003-2007Ford 6.0L Powerstroke V8 throws P0675 from cylinder 4 (passenger bank, second from front) when the FICM is borderline — cylinder 4 is one of the first to flag because of injector-driver harness routing near the EGR cooler.
- 2008-2010Ford 6.4L Powerstroke commonly throws P0675 from the under-valve-cover harness fault, same pattern as P0674.
- 2001-2010Duramax V8 throws P0675 with cylinder 4 on the passenger bank — LB7/LLY/LBZ glow plug failures are extremely common and GM eventually went to a higher-grade plug (use Bosch Duraterm or AC Delco OE, NOT cheap aftermarket).
- 2009-2016Audi/VW 2.0 TDI EA189 4-cylinder throws P0675 as the rearmost cylinder in the inline-4 — cyl 4 sits next to the firewall, runs hottest, and tends to fail first; VW dealer typically replaces all four.
- 2007-2018Cummins 6.7L inline-6 throws P0675 on cyl 4 from the same mid-block heat-soak pattern as P0674.
Estimated repair$80 (single plug, easy access) to $1,400 (full set on the Powerstroke, including UVCH harness).
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