- Ambient temperature sensor
- Harness or connector between ambient temperature sensor and air conditioning amplifier
- Air conditioning amplifier
| Last Modified: 04-05-2023 | 6.11:8.1.0 | Doc ID: RM100000000ZXIA |
| Model Year Start: 2017 | Model: Sienna | Prod Date Range: [08/2016 - ] |
| Title: HEATING / AIR CONDITIONING: AIR CONDITIONING SYSTEM: B1412/12; Ambient Temperature Sensor Circuit; 2017 - 2020 MY Sienna [08/2016 - ] | ||
|
DTC |
B1412/12 |
Ambient Temperature Sensor Circuit |
DESCRIPTION
The ambient temperature sensor is installed in front of the condenser. It detects the ambient temperature to control air conditioning AUTO mode. This sensor is connected to the air conditioning amplifier 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. The resistance of the ambient temperature sensor 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 applies voltage (5 V) to the ambient temperature sensor and reads voltage changes as the resistance of the ambient temperature sensor changes.
|
DTC Code |
DTC Detection Condition |
Trouble Area |
|---|---|---|
|
B1412/12 |
Open or short in ambient temperature sensor circuit |
|
WIRING DIAGRAM
PROCEDURE
|
1. |
READ VALUE USING TECHSTREAM |
(a) Connect the Techstream to the DLC3.
(b) Turn the ignition switch to ON.
(c) Turn the Techstream on.
(d) Enter the following menus: Body Electrical / Air Conditioner / Data List.
(e) Check the value(s) by referring to the table below.
Air Conditioner
|
Tester Display |
Measurement Item/Range |
Normal Condition |
Diagnostic Note |
|---|---|---|---|
|
Ambient Temp Sensor |
Ambient temperature sensor / Min: -23.3°C (-9.94°F) Max: 65.95°C (150.71°F) |
Actual ambient temperature displayed |
- |
OK:
The display is as specified in the Normal Condition column.
Result
|
Result |
Proceed to |
|---|---|
|
NG |
A |
|
OK (When troubleshooting according to Problem Symptoms Table) |
B |
|
OK (When troubleshooting according to the DTC) |
C |
| B |
|
PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE |
| C |
|
|
|
2. |
INSPECT AMBIENT TEMPERATURE SENSOR |
(a) Remove the ambient temperature sensor.
(b) Disconnect the ambient temperature sensor connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
1 - 2 |
10°C (50°F) |
3.00 to 3.73 kΩ |
|
15°C (59°F) |
2.45 to 2.88 kΩ |
|
|
20°C (68°F) |
1.95 to 2.30 kΩ |
|
|
25°C (77°F) |
1.60 to 1.80 kΩ |
|
|
30°C (86°F) |
1.28 to 1.47 kΩ |
|
|
35°C (95°F) |
1.00 to 1.22 kΩ |
|
|
40°C (104°F) |
0.80 to 1.00 kΩ |
|
|
45°C (113°F) |
0.65 to 0.85 kΩ |
|
|
50°C (122°F) |
0.50 to 0.70 kΩ |
|
|
55°C (131°F) |
0.44 to 0.60 kΩ |
|
|
60°C (140°F) |
0.36 to 0.50 kΩ |
NOTICE:
- Hold the sensor only by its connector. Touching the sensor may change the resistance value.
- When measuring, the sensor temperature must be the same as the ambient temperature.
HINT:
As the temperature increases, the resistance decreases (see the graph).
Text in Illustration
|
*a |
Component without harness connected (Ambient Temperature Sensor) |
|
*b |
Sensing Portion |
| NG |
|
|
|
3. |
CHECK HARNESS AND CONNECTOR (AMBIENT TEMPERATURE SENSOR - AIR CONDITIONING AMPLIFIER) |
(a) Disconnect the D75 air conditioning amplifier connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
D75-5 (TAM) - A67-1 |
Always |
Below 1 Ω |
|
D75-13 (SG-2) - A67-2 |
Always |
Below 1 Ω |
|
D75-5 (TAM) - Body ground |
Always |
10 kΩ or higher |
|
D75-13 (SG-2) - Body ground |
Always |
10 kΩ or higher |
| OK |
|
| NG |
|
REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
|