Temperature control actuator located at heater unit. It contains temp motor that changes temp door position and potentiometer that monitors position of temp door. Temperature control actuator regulates the temperature by the procedure as follows. Signal from control unit adjusts position of temp door by operating temp motor and then temperature will be regulated by the hot/cold air ratio decided by position of temp door. In operation, potentiometer delivers temp door position transformed into voltage value to A/C ECU.
The ECM sets DTC B2406 if the driver air mix actuator dosen’t move to intended position within 40sec (The ECM attempts to move the temp door for a 2 second duration at a frequency of 3 times every 20 seconds before storing a DTC.)
Item
Detecting Condition
Possible Cause
DTC Strategy
? Voltage check
? Poor connection of connected part
? Open circuit in harness
? Short circuit in harness
? Faulty DR Air Mix actuator
? Fault A/C Control Unit
Threshold value
? 0.5V<Potentiometer voltage < 4.5V
Detecting time
? 40sec
FAIL SAFE
? setting temperature : 17?-24.5?
fix at max. cooling position
? setting temperature : 25?-32?
fix at max. heating position
? Voltage value of Air Mix potentiometer as a function of temp door position.
Door position
Voltage
Error Detecting Condition
Max. cool
0.3±0.15V
Undervoltage : 0.08V or less
Max.warm
4.7±0.15V
Overvoltage : 4.9V or more