2006 Saturn Ion Owner's Manual - Page 154

Engine Coolant Temperature Gage This gage on the left measures the temperature of the vehicle's engine coolant. If the pointer moves into the shaded area, your engine is too hot! The engine cooling fan will be turned on to protect the engine and transmission. See Malfunction Indicator Lamp on page 3-36 for more information. Malfunction Indicator Lamp Check Engine Light Your vehicle has a computer which monitors operation of the fuel, ignition, and emission control systems. If the engine coolant temperature reaches 253°F (123°C) the CHK GAGE message will appear and a chime will sound to alert you to the engine coolant temperature gage. See Message Center on page 3-43. If you have been operating your vehicle under normal driving conditions, you should pull off the road and stop your vehicle, be sure the air conditioning is off, let the engine idle for a few minutes, then turn off the engine. If your engine control system detects a failure in the engine coolant temperature circuit, the malfunction indicator lamp (service engine soon) light will come on. The coolant gage may read all the way hot or cold. This system is called OBD II (On-Board Diagnostics-Second Generation) and is intended to assure that emissions are at acceptable levels for the life of the vehicle, helping to produce a cleaner environment. The check engine light comes on to indicate that there is a problem and service is required. Malfunctions often will be indicated by the system before any problem is apparent. This may prevent more serious damage to your vehicle. This system is also designed to assist your service technician in correctly diagnosing any malfunction. 3-36