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P0672 is a diagnostic trouble code (DTC) for "Cylinder 2 Glow Plug Circuit". This can happen for multiple reasons and a mechanic needs to diagnose the specific cause for this code to be triggered in your situation. Our certified mobile mechanics can come to your home or office to perform the Check Engine Light diagnostic. Once we are able to diagnose the problem, you will be provided with an upfront quote for the recommended fix and receive $20.00 off as a credit towards the repair. All our repairs are backed by our 12-month / 12,000-mile warranty.
The P0672 code is an OBD-II generic code indicating a problem with the cylinder 2 glow plug circuit.
P0672 applies to diesel vehicles and it means that the glow plug in cylinder #2 has failed to produce the high level of heat required to perform a cold start in a diesel engine. All diesels devices to heat the cylinders enough to ignite the fuel when the engine is cold, and this code identifies the #2 glow plug circuit as the problem.
You may see this code for several reasons:
Because the job of the glow plug is to help the diesel engine to turn over in cold weather, the symptoms are often very obvious. However, with a single faulty plug, you may see only a "check engine" light and minimal signs of a problem. In fact, most diesel engines can start with a single faulty plug. When temperatures are below freezing, though, the symptoms may include:
Mechanics will need to use their DVOM (digital volt ohm meter) to perform the diagnostic tests. Begin by disconnecting wiring to the #2 cylinder glow plug, and placing the DVOM on ohms before touching the red lead to the glow plugs empty terminal and grounding the black lead. The range must be .5 to 2.0 ohms. Next, the mechanic must consider resistance in the glow plug wire and the relay buss bar on the valve cover. This is done by placing the red lead to the buss bar number one wire and the black to the side of the glow plug. The same range of .5 to 2.0 ohms is needed. If it is too high, replace your lead wired to the plug from the buss bar.
Reconnect the wires and visually examine for any signs of cracks or failed insulation. Test with code reader connected to the OBD by turning the key, leaving the engine off and clearing the codes.
It is not advisable to replace any of the glow plug timers and relays before properly diagnosing the connections. Failing to test wiring and connectors, as well as the glow plugs, easily causes mistakes in the diagnostic process.
The P0672 code will not, usually, prevent a vehicle from starting. If it is only one bad plug, the engine can continue to start. However, over time and changing temperature, the engine may become more and more difficult to start if sitting in cold weather, and this issue can cause a loss in power and acceleration.
The most common repairs needed to fix the P0672 code include:
Voltage in the system exceeding 10% of that suggested by a vehicle's manufacturer will typically cause this code to be stored in the system, and for a check engine light to illuminate.
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