The Ambient Temperature is a NTCT type thermistor and is use for temperature regulation including blower motor level and mix mode control .
DTC B1238 sets if Ambient Temperature sensor signal is at or over 4.9V for 0.3 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
Ignition ON
Threshold value
Ambient Temperature sensor signal is at or over 4.9V for 0.3 seconds
Failsafe
Displayed '--' and A/C control Module regards and controls it as 20?(68?)
? Resistance value of ambient temp.sensor as a function of temperature.
Temperature(?/?)
Resistance(?)
-20/-4
271.4
50/122
11
0/32
95.1
60/140
7.58
25/77
30