Ambient Temperature Input Strategy

ATC ECU incorporates a software strategy to overcome effects of radiant heat from engine and cooling systems on ambient temperature sensor. At vehicle speeds of 15 MPH or more, input is considered valid and changes are accepted. Input value is stored in memory and constantly updated while vehicle speed is more than 15 MPH. At vehicle speeds less than 15 MPH, changes of input values are considered suspect and changes are ignored. In place of actual input, ATC ECU uses value stored in memory. When ignition is turned on, if ATC ECU detects warm heater coolant, it uses ambient temperature stored in memory. If ATC ECU detects cold coolant temperature, ambient temperature sensor input is used.