AL fault codes rely upon certain setpoints. See Systems Operation, "Service Mode" for more information on setpoints. AL fault codes are not stored in the fault log of the GSC. Many of the AL fault codes are programmable as a fault alarm or as a fault shutdown. To show the severity of the fault, the AL fault codes are accompanied by the fault alarm indicator, or the fault shutdown indicator on the GSC. The AL fault codes and the related setpoints are described in the paragraphs that follow.
AL1 High Water Temperature Alarm - The GSC issues a high water temperature shutdown when the engine coolant temperature increases close to 6 deg C (11 deg F) of setpoint P15. The fault alarm indicator will FLASH. The AL1 fault code is shown on the upper display after the "Alarm Fault Codes" key is pressed.
P15 is the setpoint for high water temperature shutdown. P15 adjusts the coolant temperature. When the setpoint is reached, the dedicated shutdown indicator for high water temperature FLASHES and the engine is shutdown.
AL2 Low Water Temperature Alarm - When the engine coolant temperature decreases to setpoint P16 (low water temperature alarm), the GSC issues a low water temperature alarm. The fault alarm indicator will FLASH. The AL2 fault code is shown on the upper display after the Alarm Fault condition is initiated.
P16 is the setpoint for the low water temperature alarm. P16 tells the GSC in order to declare that a low water temperature fault exists.
AL3 Low Engine Oil Pressure Alarm - The GSC issues an alarm when the oil pressure drops within 34 kPa (5 psi) of the P13 setpoint or the P14 setpoint. The fault alarm indicator will FLASH. The "AL3" fault code is shown on the upper display after the Alarm Fault condition is initiated.
P13 is the setpoint for low oil pressure shutdown at rated speed. P13 signals the GSC in order to indicate a fault. When the setpoint is reached, the dedicated shutdown indicator for low oil pressure flashes and the engine is shut down.
P14 is the setpoint for low oil pressure shutdown at idle speed. P14 signals the GSC in order to indicate a fault. When the setpoint is reached, the dedicated shutdown indicator for low oil pressure FLASHES and the engine is shutdown.
AL4 Fault Indication By Engine ECM - The AL4 fault occurs when the electronic control module (ECM) for the engine detects an alarm fault or a shutdown fault. The engine ECM tells the GSC whether the AL4 fault is an alarm fault or a shutdown fault. This includes faults that include derating of the engine. The occurrence of an AL4 fault code could mean that the engine ECM is not programmed correctly. Refer to the Troubleshooting, SENR1003, "3500B EPG Engines". The "AL4" fault (P23) is disabled on MUI engines and gas engines.