The DTC code P0672 OBDII refers to diesel engines and indicates a problem in the glow plug. This glow plug is used to raise the temperature for a few seconds while starting the engine in cold weather. Diesel relies entirely on the high level of heat to ignite and this is achieved through compression.
The glow plug is installed in the cylinder head very close to the starting point of combustion. This point can be the main chamber. When the engine management computer detects a low temperature, it activates the glow plugs to help the engine reach the temperature required for proper operation. When this code is set, it is because there is a malfunction in the glow plug circuit, the problem causes the number 2 glow plug to not heat up.