OBD-II Code
P0673
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 DIY) to $1,400 (full set plus GPCM).
P0673 means the ECU detected a fault in the glow plug circuit feeding cylinder 2 specifically — open circuit, short to ground, or resistance out of spec, flagged by the Glow Plug Control Module during the cold-start 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 procedureP0673 means the ECU detected a fault in the glow plug circuit feeding cylinder 2 specifically — open circuit, short to ground, or resistance out of s…
P0673 means the ECU detected a fault in the glow plug circuit feeding cylinder 2 specifically — open circuit, short to ground, or resistance out of spec, flagged by the Glow Plug Control Module during the cold-start glow cycle.
The cheapest-first diagnostic ladder is identical to any per-cylinder glow code
- Pull the glow plug harness connector at cylinder 2 and ohm the plug at its terminal — healthy plug reads 0.4-2.0 ohms cold (typical 0.6-1.2 ohms), 0 ohms means shorted, infinite/OL means open/burned, 4+ ohms means marginally weak and is the most common cold-start hard-start root cause.
- Verify the GPCM is sending the PWM command at 0-100% duty cycle with glow-on time of 5-30 sec scaled to coolant temp — below 20F coolant the glow cycle runs the full 30 sec, above 60F it may only run 5-8 sec.
- Clamp an inductive amp probe on the cylinder 2 glow plug feed and look for 7-20A initial inrush falling to 5-15A as the plug heats. A reading of 0A with the GPCM commanded ON points to an open between module and plug (bad wire, broken pin, dead plug); a steady 20A+ that won't drop points to a shorted plug. 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 P0673 from cylinder 2 (passenger front) when the FICM voltage drops under 45V and starves the GPCM logic; c…
- 2003-2007Ford 6.0L Powerstroke V8 throws P0673 from cylinder 2 (passenger front) when the FICM voltage drops under 45V and starves the GPCM logic; check FICM voltage on the scan tool before condemning the plug.
- 2001-2010Duramax LB7/LLY/LBZ V8 throws P0673 with cylinder 2 on the passenger bank — Duramax uses an alternating bank layout (cyl 1-3-5-7 driver, 2-4-6-8 passenger), so a P0673 sends you to the right-front cylinder, not next to P0672; the EGR cooler overhang traps heat over cylinder 2 and toasts the pigtail.
- 2007-2018Cummins 6.7L inline-6 throws P0673 from harness corrosion at the front of the head where road salt and washer-fluid overspray collect.
- 2009-2016Audi/VW 2.0 TDI EA189 4-cylinder (Jetta, Passat, A3) throws P0673 most often after a Dieselgate-era emissions remap stresses the glow plugs harder; VW TSBs reference replacing all four together.
Estimated repair$80 (single plug DIY) to $1,400 (full set plus GPCM).
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