Theory Of Operation
WARNING: This page is about a different car, the 2014 RAM 1500. However, it is still accessible from the selected car via links, so may be relevant.
This diagnostic detects Thermostat stuck open failures. This can result in coolant warm-up delay or coolant temperature drop during engine operation. The warm-up behavior test monitors the measured engine coolant temperature for warm-up after engine start. The measured temperature is compared to a model of engine coolant temperature based on normal warm up characteristics. The steady-state test monitors engine coolant temperature drop during engine operation. The described rationality checks will detect coolant thermostat (coolant temperature below thermostat regulating temperature) failures.