Intake door located at heater unit controls the inlet of car. It contains intake motor that changes intake door position and potentiometer that monitors position of intake door. When driver operates the intake switch, ECU receives mode signal from intake switch and operates intake door motot to turn intake door to intended position. (with FRE mode signal, intake door is closed and with REC mode signal, intake door is opened)
In operation, potentiometer delivers intake door position transformed into voltage value to A/C ECU .
The ECM sets DTC B1209 if there is a short to power in the Intake actuator signal harness.
Item
Detecting Condition
Possible Cause
DTC Strategy
? Voltage check
? Open circuit in ground harness
? Short to power in signal harness
? Faulty Intake potentiometer
Threshold value
?< 4.9V
Detecting time
? 0.3sec
FAIL SAFE
? Setting mode : REC
Fix at REC position
? Setting mode : Except REC
Fix at FRE position
? Voltage value of Intake potentiometer as a function of position of Intake door.
Door position
Voltage
Error Detecting Condition
FRE
0.3±0.15V
Undervoltage : 0.08V or less
REC
4.7±0.15V
Overvoltage : 4.9V or more