HEATING / AIR CONDITIONING AIR CONDITIONING SYSTEM(for Gasoline Model (NR Series) with Manual Air Conditioning System for Mechanical Control Type) B1412 Ambient Temperature Sensor Circuit
DESCRIPTION
The thermistor assembly is installed in front of the cooler condenser assembly to detect the ambient temperature, which is used to control the air conditioning system. This sensor is connected to the air conditioning amplifier assembly and detects fluctuations in the ambient temperature. This data is used for controlling the cabin temperature. The sensor sends a signal to the air conditioning amplifier assembly. The resistance of the thermistor assembly changes in accordance with the ambient temperature. As the temperature decreases, the resistance increases. As the temperature increases, the resistance decreases.
The air conditioning amplifier assembly applies voltage (5 V) to the thermistor assembly and reads voltage changes due to changes in the resistance of the thermistor assembly.
| DTC No. | Detection Item | DTC Detection Condition | Trouble Area | Memory |
|---|---|---|---|---|
| B1412 | Ambient Temperature Sensor Circuit | Open or short in ambient temperature sensor circuit | ·
Thermistor assembly ·
Harness or connector ·
Air conditioning amplifier assembly |
Memorized
(4 sec. or more)* |
*: The air conditioning amplifier assembly stores this DTC if the malfunction has occurred for the period of time indicated in the brackets.
- HINT:
-
If the ambient temperature is approximately -52.9°C (-63.22°F) or lower, DTC B1412 may be stored even though the system is normal.
WIRING DIAGRAM
PROCEDURE
Connect the GTS to the DLC3.
Turn the ignition switch to ON.
Turn the GTS on.
Enter the following menus: Body Electrical / Air Conditioner / Data List.
Read the Data List according to the display on the GTS.
- Body Electrical > Air Conditioner > Data List
-
Tester Display Measurement Item Range Normal Condition Diagnostic Note Ambient Temp Sensor Thermistor assembly Min.: -23.30°C (-9.94°F)
Max.: 65.95°C (150.71°F)Actual ambient temperature displayed Thermistor assembly circuit malfunction
·When open circuit: -23.30°C (-9.94°F)
·When short circuit: 65.95°C (150.71°F)
- Body Electrical > Air Conditioner > Data List
-
Tester Display Ambient Temp Sensor - 50003 121 2
- OK:
The display is as specified in the normal condition column.
- Result:
Proceed to OK NG
OK
NG
Remove the thermistor assembly.
Inspect the thermistor assembly.
- Result:
Proceed to OK NG
OK
NG
Disconnect the I162 air conditioning amplifier assembly connector.
Measure the resistance according to the value(s) in the table below.
- Standard Resistance:
Tester Connection Condition Specified Condition A3-1 - I162-34 (TAM) Always Below 1 Ω A3-2 - I162-35 (SG-2) Always Below 1 Ω A3-1 or I162-34 (TAM) - Other terminals and body ground Always 10 kΩ or higher A3-2 or I162-35 (SG-2) - Other terminals and body ground Always 10 kΩ or higher
- Result:
Proceed to OK NG
OK
NG