P0673
Cylinder 3 Glow Plug Circuit/Open
Glow plugs (diesel)
Generic OBD-II
High
What it means
P0673 is a diesel code meaning the control module detected an open (broken) circuit to the glow plug on cylinder 3. Glow plugs pre-heat the combustion chamber for cold starting, so a dead plug causes hard starts, rough running when cold, and extra smoke until the engine warms up.
High
Can I keep driving? Drivable once warm, but expect hard cold starts and rough cold running until the glow plug circuit is repaired.
Common symptoms
What you'll notice
- Hard starting when the engine is cold
- Rough running and shaking for the first minute after a cold start
- White or grey smoke from the exhaust on cold start-up
- Check-engine (or glow plug) light on
Common causes
Most likely first
- Failed glow plug on cylinder 3 (open circuit)Likely
- Open or shorted wiring to the cylinder 3 glow plugCommon
- Corroded or loose glow plug connectorCommon
- Faulty glow plug control moduleLess often
How to diagnose & fix
Work through it in order
- Read freeze-frame data and confirm the fault is specific to cylinder 3.
- Measure the resistance of the cylinder 3 glow plug — an open (infinite) reading means it is failed.
- Inspect the wiring and connector from the control module to that glow plug for breaks or corrosion.
- Replace the failed glow plug (and clean/repair the connection).
- If the plug and wiring are good, test the glow plug control module. Clear and re-test.
FAQ
Quick answers
Is it safe to drive with P0673?+
Yes, once the engine is running and warm it drives normally. The main effect is hard cold starting and rough cold idle, which worsens in cold weather.
Can I just clear P0673?+
It will come back until the open glow plug or its wiring is repaired. A single dead glow plug won't clear itself.
Related codes
Often seen with P0673
Read & clear P0673 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX