168 OPERATION If a pyrometer is installed, the idle cooldown function will use the pyrometer reading, shutting the engine down when the temperature drops below 232°C (450°F), or after 3.5 minutes, whichever comes first. The default for this option is set at OFF from the factory. Note: The parking brake must be on for the idle cooldown function to work. Engine Shutdown System (If Enabled) The engine is protected by a system that prevents engine damage by shutting down the engine whenever a potentially damaging condition (such as loss of oil pressure, loss of coolant or engine overheating) is detected. If the system detects such a condition, a warning indicator light and an alarm will alert the driver before the engine actually shuts down. Pressing the Shutdown Override Switch on the instrument panel shortly after the vehicle sounds the engine shutdown alarm, allows 30 additional seconds of operation. This process can be repeated several times to safely park the vehicle. Engine Shutdown Indicator — During normal operating conditions, this indicator should illuminate as soon as the key switch is turned on. After the engine is started, it will remain illuminated until engine oil pressure reaches normal idling range. During shutdown, if the system detects a condition that could lead to engine failure, the Engine Shutdown indicator will illuminate prior to engine shutdown.