In case of engine cold starting, Air conditioner control module receies engine coolant temperature sensor signal through the CAN signal so that Mode is changed to DEF with controlling mode actuator.
Air conditioner Control Module sets DTC B1687 if engine temperature sensor signal has not been received through the CAN signal.
Item
Detecting Condition
DTC Strategy
Check CAN signal
Faulty engine coolant temperature sensor
CAN communication
Enable Conditions
IG KEY ON
Threshold value
No signal via CAN for 1.5 seconds or receiving Error value
Failsafe
Regarded it as -2?(28.4?)