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Great info that's some crazy stuff built into the computer. ThanksPowertrain Cooling
The message center provides a warning message to inform the driver that vehicle performance is reduced to allow the engine to cool. This feature is part of the smart cooling function in the PCM and provides powertrain cooling protection under high ambient temperature conditions.
Fail Safe Cooling
A strategy called fail safe cooling is built into the PCM that controls the engine if it starts to overheat.
Fail safe cooling has two modes: A closed loop mode that relies on a CHT 2 sensor and an open loop mode that relies on an ECT sensor. When the engine starts to overheat, the decision to go into closed loop or open loop mode is made based on sensor availability and sensor failures. Closed loop mode takes priority over open loop. The reason is that a good CHT 2 sensor can reliably track engine temperature at all times, while the ECT sensor fails to do so.
Closed Loop Mode
Stage 1 of the strategy begins if the engine starts to overheat. The CHT 2 sensor transmits a signal to the PCM , which moves the temperature gauge pointer into the red zone.
If the engine is not switched off and the temperature continues to rise, the Powertrain Check Lamp is illuminated. This indicates to the driver that the engine is approaching critical limits and should be stopped. At this point DTC P1285 sets in the PCM and is retrieved using a scan tool.
Stage 2 of the strategy begins if the lamp and temperature gauge are ignored by the driver. The PCM starts to control the engine by cutting out 2 cylinders and restricting load. The RPM will be limited below 3,000 RPM initially then slowly ramped down with time to as low as 800 RPM . Simultaneously the MIL illuminates. This indicates that long term engine damage can occur and vehicle emissions will be affected. At this point DTC P1299 sets in the PCM and is retrieved using a scan tool.
Air is drawn into the deactivated cylinders to help control the temperature of the engine internal components. The deactivated cylinders alternate to allow even cooling of all the cylinders.
Stage 3 of the strategy begins if the engine temperature continues to rise. This results in the engine being totally disabled before major engine damage or seizure occurs. The Powertrain Check Lamp begins to flash, indicating to the driver that the engine will be switched off after 30 seconds. This allows the driver time to choose a suitable parking place.
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