The Ambient Temperature sensor is a negative temperature coefficient thermistor that is located at the center stay of the condenser. The Ambient Temperature Sensor signal is used by the A/C ECU when making calculations related to blower motor, temperature, and mode door calculations.
Air conditioner Control Module sets DTC B1238 if Ambient sensor has been detected over 4.9V for 4 seconds.
Item
Detecting Condition
DTC Strategy
Voltage check
Poor Connection in harness
Open in signal circuit
Shrot to battery in signal circuit
Faulty Ambient Temperature sensor
Faulty air condtioner control Module
Enable Conditions
IG KEY ON
Threshold value
Ambient Temperature sensor has been detected over 4.9V for 4 seconds.
Failsafe
Displayed '--' and A/C control Module regards and controls it as 20?(68?)
Temperature(?/?)
Resistance(?)
-20/-4
284.5
50/122
10.8
0/32
97.5
70/158
5.2
25/77
30