Operation with ignition OFF
ECM regulates the fans when the ignition is off based on coolant temperature or how the exhaust temperature has been previously.
Note that all afterrunning occurs at speed 2.
- Based on coolant temperature: 1.a. If the temperature is <103°C when the ignition is off, the radiator fans remain off. 1.b. If the temperature is >103°C when the ignition is off, afterrunning operates max 420 seconds or until coolant temperature is below 103°C.
- Based on calculated exhaust temperature: Exhaust temperature is continually calculated in ECM. When certain temperature levels are exceeded when the ignition is off, afterrunning operates. Afterrunning operates in the following cases: The calculated exhaust temperature has exceeded 700°C for 2 minutes without subsequently falling below 700°C for 1 minute. The calculated exhaust temperature has exceeded 750°C for 1 minute without subsequently falling below 750°C for 4 minutes.