- Ambient temperature sensor
- Harness or connector between ambient temperature sensor and air conditioning amplifier assembly
- Air conditioning amplifier assembly
| Last Modified: 11-27-2007 | 1.6 C | |
| Service Category: Vehicle Interior | Section: Heating/Air Conditioning | |
| Model Year: 2008 | Model: LX570 | Doc ID: RM000002LJ4009X |
| Title: HEATING / AIR CONDITIONING: AIR CONDITIONING SYSTEM: DESCRIPTION (2008 LX570) | ||
|
DTC |
B1412/12 |
Ambient Temperature Sensor Circuit |
DESCRIPTION
The ambient temperature sensor is installed in the front part of the condenser to detect the ambient temperature and control the air conditioner auto mode. The sensor connected to the air conditioning amplifier assembly detects fluctuations in the ambient temperature. This data is used for controlling the room temperature. The sensor sends a signal to the air conditioning amplifier assembly. 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 assembly 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 |
An open or short in the ambient temperature sensor circuit. |
|
WIRING DIAGRAM
INSPECTION PROCEDURE
PROCEDURE
|
1. |
READ VALUE USING TECHSTREAM (AMBIENT TEMPERATURE SENSOR) |
(a) Use the Data List to check if the ambient temperature sensor is functioning properly.
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 |
Open in the circuit: -53°C (-63.4°F). Short in the circuit: 126°C (258.8°F). |
OK:
The display is as specified in the normal condition.
|
|
2. |
INSPECT AMBIENT TEMPERATURE SENSOR |
(a) Remove the ambient temperature sensor
.
(b) 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:
- Even slightly touching the sensor may change the resistance value. Be sure to hold the connector of the sensor.
- When measuring, the sensor temperature must be the same as the ambient temperature.
HINT:
As the temperature increases, the resistance decreases (See the graph).
|
|
3. |
CHECK HARNESS AND CONNECTOR (AMBIENT TEMPERATURE SENSOR - AIR CONDITIONING AMPLIFIER) |
(a) Disconnect the A14 sensor connector.
(b) Disconnect the E35 amplifier connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
A14-1 (+) - E35-10 (TAM) |
Always |
Below 1 Ω |
|
A14-2 (-) - E35-16 (SG-2) |
||
|
E35-10 (TAM) - Body ground |
Always |
0.5 to 35 kΩ |
|
E35-16 (SG-2) - Body ground |
Always |
Below 1 Ω |
|
|
|