What Does P0672 Mean?
The PCM has detected a malfunction in the cylinder 2 glow plug circuit on a diesel engine. The glow plug is either open-circuit, shorted, or showing resistance outside the expected range. This means cylinder 2 is not receiving adequate pre-heat for cold-start combustion. The driver will notice slightly harder cold starting, a brief rough idle during warm-up, and possible white smoke from the exhaust on cold starts.
Common Causes
40%
Failed cylinder 2 glow plug (open or degraded element)
25%
Corroded or loose bus bar connection at cylinder 2
20%
Wiring fault in cylinder 2 glow plug circuit
10%
Glow plug control module cylinder 2 driver failure
5%
Seized glow plug that has cracked during thermal cycling
Diagnostic Steps
1
Measure cylinder 2 glow plug resistance with the connector removed — spec is 0.5-2.0 ohms. An OL reading means the element is burned out; a near-zero reading means it is shorted.
2
Compare the cylinder 2 glow plug resistance to all other cylinders. If cylinder 2 is significantly different, that confirms the plug is faulty.
3
Check the bus bar or individual connector for cylinder 2 — verify the connection is tight, clean, and making full contact. Corrosion here is common due to the high-heat environment.
4
Verify glow plug module output for cylinder 2 by measuring voltage at the bus bar during the glow cycle. If voltage is present but the plug is not heating, the plug has failed.
5
If replacing the glow plug, use the correct torque specification (typically 10-15 Nm) and apply anti-seize compound to the threads to prevent future seizure in the cylinder head.
Estimated Repair Cost
$60 - $350
Parts + labor, varies by vehicle and location
The PCM has detected a malfunction in the cylinder 2 glow plug circuit on a diesel engine. The glow plug is either open-circuit, shorted, or showing resistance outside the expected range. This means cylinder 2 is not receiving adequate pre-heat for cold-start combustion. The driver will notice sligh...
The most common cause of P0672 (Cylinder 2 Glow Plug Circuit) is: Failed cylinder 2 glow plug (open or degraded element)
Typical repair costs for P0672 range from $60 to $350, depending on the vehicle, location, and whether you do it yourself or go to a shop.
A single failed glow plug causes harder cold starting and white smoke but is not a safety hazard. Once the engine reaches operating temperature, performance is normal. If multiple glow plugs fail, cold starting may become impossible. Repair before cold weather season.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0672 to identify the root cause.
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Quick Info
Category
Powertrain
System
Diesel Glow Plug System
Difficulty
Type
Generic (SAE)
Recommended Tools
OBD2 Scanner
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