ELECTRONICS GP 3806219 - Caterpillar

engine ECM monitors the engine coolant temperature in order to protect the engine in case of a problem with the coolant temperature. The coolant temperature sensor is mounted in the water jacket and the sensor is located toward the front of the engine. The exact location of the engine coolant temperature sensor varies depending on the engine model. The GSC monitors the oil pressure that is read by the engine ECM.The sensor is connected to the engine ECM. The engine ECM sends the data on the coolant temperature to the GSC by the CAT data link. Refer to Troubleshooting, SENR1003, "3500B EPG Engines" for more information on the coolant temperature sensor for the engine ECM. Note: The GSC is usually programmed to treat a fault with the coolant temperature sensor as an alarm fault (P04 = 0). The GSC is usually programmed to treat a fault with the coolant temperature sensor as a shutdown fault (P04 = 1). The diagnostic codes are automatically shown on the upper display.ProcedureThe possible causes of this diagnostic code are the open circuit of the CAT data link between the engine ECM and the GSC. Another cause could be a short or a fault on the oil pressure sensor connected to the engine ECM. The GSC issues a CID 110 FMI 2 in order to show that the GSC is unable to receive any valid data on the coolant temperature from the engine ECM. If a CID 248 FMI 9 is present, refer to the troubleshooting procedures for that diagnostic code. If a diagnostic code for the coolant temperature is originating from the engine ECM, refer to Troubleshooting, SENR1003, "3500B EPG Engines" for information on troubleshooting that diagnostic code.