SYSTEM / ECM System PREHEATING CONTROL Purpose: Warm the engine, makes the engine start, and reduces white smoke and noise when starting the engine. Preheats after the engine starts and makes idling immediately when the engine stars. Operation: 1. The coolant temperature sensor sends the sig- nals according to coolant temperature to ECM. 2. When the key switch is turned ON, electrical cur- rent from terminal M in the key switch flows to the glow plug relay. 3. ECM connects the ground circuit of glow plug re- lay according to the signals from coolant tem- perature sensor and controls time for continuity of electrical current for the glow plug.
Coolant Tem- perature Sensor From Terminal M in Key Switch Fuse Box ECM From Battery Glow Plug Relay T1J1-02-03-002 Glow Plug T2-3-11