Cylinder 2 Glow Plug Circuit
The P0672 code means the vehicle's onboard diagnostic system has detected: Cylinder 2 Glow Plug Circuit. This is a moderate severity code.
- Keep driving?
- Short distances only
- DIY difficulty
- moderate
- Estimated cost
- $50 - $500 (parts and labor)
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Common Symptoms
- Check Engine Light on
- Cylinder 2 glow plug not heating
- Reduced system performance
- Warning indicators on dashboard
Probable Causes (Ranked by Likelihood)
- Failed glow plug in Cylinder 2 Very High
- Wiring damage or corrosion in the circuit High
- Poor electrical connection at module or component Moderate
- ECM or control module internal failure Low
Step-by-Step Diagnostic Procedure
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Use a scan tool to read data related to Cylinder 2 Glow Plug
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Inspect all related wiring, connectors, and grounds for damage, corrosion, or loose connections
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Measure circuit voltage, resistance, and continuity to identify the fault type
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Check for technical service bulletins related to this code for your specific vehicle
Common Fixes by Vehicle
What techs usually find when diagnosing P0672 on specific vehicles — tap your vehicle for the fix and the exact part:
2001-2010 Chevy/GMC Duramax 6.6L hard DIY
P0672 = Glow Plug #2 circuit. Replace all 8 glow plugs with AC Delco 12663045 or NGK Y-505J. Use a proper torque wrench -- overtightening breaks the tip into the cylinder, undertightening causes gas leaks. 11 ft-lb is the spec. A blown plug usually also shows low compression at the cylinder when tested.
Labor: 3-4 hours (all 8)2003-2007 Ford 6.0L Power Stroke hard DIY
6.0L P0672 is glow plug #2. When replacing 6.0L glow plugs, use anti-seize on the threads but keep it off the tip. Motorcraft ZD-11 is the OE plug. If a plug is seized, soak with penetrating oil overnight and work it back and forth -- a broken tip in the cylinder is a $5K-plus mistake.
Labor: 4-6 hours (all 8)2008-2010 Ford 6.4L Power Stroke hard DIY
6.4L P0672 = glow plug #2. Repeat P0672 after replacement usually points to harness damage between the glow plug and the GPCM. Inspect the harness for rubbing on the EGR cooler or turbocharger. Repair with Raychem solder-seal connectors.
Labor: 6-10 hours (cab-off recommended)Frequently Asked Questions
What happens when Cylinder 2 glow plug fails?
A single failed glow plug in Cylinder 2 may cause hard starting in cold weather and rough running until the engine warms up. In mild temperatures, you may not notice any symptoms. Multiple failed glow plugs cause progressively worse cold starting.
How much does a glow plug replacement cost?
Individual glow plugs cost $15 to $50 each. Labor is the main expense as some glow plugs are difficult to access. A single glow plug replacement typically costs $100 to $300. Many shops recommend replacing all glow plugs at once.
Can a glow plug break off during removal?
Yes, especially on high-mileage diesel engines. Carbon buildup and corrosion can seize the glow plug in the cylinder head. Special extraction tools exist for broken glow plugs. Applying penetrating oil days before removal helps.
Sources
This page is built from documented references. Verify against your own service info before repair work.
P0672 on Diesel, EV & Equipment
The same code ID appears across other engines and platforms. The diagnostic flow varies by manufacturer — these are the platform-specific breakdowns:
See All Codes & Fixes for Your Vehicle
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