DTC B1412/12 Ambient Temperature Sensor Circuit |
for Preparation Click here
DESCRIPTION
This sensor detects the temperature outside the cabin and sends the appropriate signals to the A/C amplifier via the CAN communication system.DTC No. | DTC Detection Condition | Trouble Area |
B1412/12 | Open or short in ambient temperature sensor circuit |
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WIRING DIAGRAM
INSPECTION PROCEDURE
1.CHECK CAN COMMUNICATION SYSTEM (COMBINATION METER - A/C AMPLIFIER) |
Use the Techstream.
Check that the CAN communication system functions normally between the combination meter and the A/C amplifier.
- Result:
Result Proceed to CAN DTC is not output A CAN DTC is output B
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A | |
2.READ VALUE USING TECHSTREAM |
Connect the Techstream to the DLC3.
Turn the ignition switch to ON.
Turn the Techstream on.
Enter the following menus: Body / Air Conditioner / Data List.
Check the value(s) by referring to the table below.
Air Conditioner Tester Display Measurement Item/Range Normal Condition Diagnostic Note Ambient Temp Sensor
(Ambi Temp Sens)Ambient temperature sensor / Min: -23.3°C (-9.94°F), Max: 65.95°C (150.71°F) Actual ambient temperature displayed Open in circuit: -23.3°C (-9.94°F)
Short in circuit: 65.95°C (150.71°F)- 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 DTC) C
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A | |
3.CHECK HARNESS AND CONNECTOR (AMBIENT TEMPERATURE SENSOR CIRCUIT) |
Disconnect the connector from the combination meter.
Measure the resistance according to the value(s) in the table below.
- Standard Resistance:
Tester Connection Condition Specified Condition E46-9 (TX1+) - E46-23 (TEMP) Outside temperature:
25°C (77°F)1.60 to 1.80 kΩ E46-9 (TX1+) - E46-23 (TEMP) Outside temperature:
40°C (104°F)0.80 to 1.00 kΩ
- HINT:
- As the temperature increases, the resistance decreases.
Text in Illustration *a Front view of wire harness connector
(to Combination Meter)
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OK | |
4.REPLACE COMBINATION METER |
Replace the combination meter (Click here).
- HINT:
- Since the combination meter cannot be inspected while it is removed from the vehicle, replace the combination meter with a known good one and check that the condition returns to normal.
Check for DTCs.
- Result:
Result Proceed to DTC B1412 is not output A DTC B1412 is output B
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A | ||
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5.INSPECT AMBIENT TEMPERATURE SENSOR |
Remove the ambient temperature sensor.
Disconnect the connector from the ambient temperature sensor.
Measure the resistance according to the value(s) in the table below.
- Standard Resistance:
Tester Connection Condition Specified Condition A23-1 - A23-2 10°C (50°F) 3.00 to 3.73 kΩ A23-1 - A23-2 15°C (59°F) 2.45 to 2.88 kΩ A23-1 - A23-2 20°C (68°F) 1.95 to 2.30 kΩ A23-1 - A23-2 25°C (77°F) 1.60 to 1.80 kΩ A23-1 - A23-2 30°C (86°F) 1.28 to 1.47 kΩ A23-1 - A23-2 35°C (95°F) 1.00 to 1.22 kΩ A23-1 - A23-2 40°C (104°F) 0.80 to 1.00 kΩ A23-1 - A23-2 45°C (113°F) 0.65 to 0.85 kΩ A23-1 - A23-2 50°C (122°F) 0.50 to 0.70 kΩ A23-1 - A23-2 55°C (131°F) 0.44 to 0.60 kΩ A23-1 - A23-2 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 *c Resistance (kΩ) *d Allowable Range *e Temperature (°C (°F))
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OK | ||
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