| Last Modified: 08-21-2023 | 6.11:8.1.0 | Doc ID: RM100000001A3NY |
| Model Year Start: 2019 | Model: Avalon HV | Prod Date Range: [04/2018 - ] |
| Title: HEATING / AIR CONDITIONING: AIR CONDITIONING SYSTEM (for HV Model): B1412; Ambient Temperature Sensor Circuit; 2019 - 2022 MY Avalon HV [04/2018 - ] | ||
|
DTC |
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 |
|
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
|
1. |
READ VALUE USING TECHSTREAM |
(a) Connect the Techstream to the DLC3.
(b) Turn the power switch on (IG).
(c) Turn the Techstream on.
(d) Enter the following menus: Body Electrical / Air Conditioner / Data List.
(e) Read the Data List according to the display on the Techstream.
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
|
Body Electrical > Air Conditioner > Data List
|
Tester Display |
|---|
|
Ambient Temp Sensor |
OK:
The display is as specified in the normal condition column.
| OK |
|
REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY
|
|
|
2. |
INSPECT THERMISTOR ASSEMBLY |
(a) Remove the thermistor assembly.
Click here
![2019 - 2021 MY Avalon HV [04/2018 - 08/2021]; HEATING / AIR CONDITIONING: AMBIENT TEMPERATURE SENSOR (for HV Model): REMOVAL](/t3Portal/stylegraphics/info.gif)
(b) Inspect the thermistor assembly.
Click here
| NG |
|
REPLACE THERMISTOR ASSEMBLY
|
|
|
3. |
CHECK HARNESS AND CONNECTOR (THERMISTOR ASSEMBLY - AIR CONDITIONING AMPLIFIER ASSEMBLY) |
(a) Disconnect the G36 air conditioning amplifier assembly connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
A14-2 - G36-13 (TAM) |
Always |
Below 1 Ω |
|
A14-1 - G36-2 (SG-2) |
Always |
Below 1 Ω |
|
A14-2 or G36-13 (TAM) - Other terminals and body ground |
Always |
10 kΩ or higher |
|
A14-1 or G36-2 (SG-2) - Other terminals and body ground |
Always |
10 kΩ or higher |
| OK |
|
REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY
|
| NG |
|
REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
|