Dtc B1412/12 Ambient Temperature Sensor Circuit

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

CHECK CAN COMMUNICATION SYSTEM (COMBINATION METER - A/C AMPLIFIER)

READ VALUE USING TECHSTREAM

CHECK HARNESS AND CONNECTOR (AMBIENT TEMPERATURE SENSOR CIRCUIT)

REPLACE COMBINATION METER

INSPECT AMBIENT TEMPERATURE SENSOR

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

1. Use the Techstream.
   

2. 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

1. Connect the Techstream to the DLC3.
   

2. Turn the ignition switch to ON.
   

3. Turn the Techstream on.
   

4. Enter the following menus: Body Electrical / Air Conditioner / Data List.
   

5. 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

1. Disconnect the connector from the combination meter.
   

2. 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)

1. Replace the combination meter (COROLLA_ZRE142 RM0000024D7032X.html).
   

   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.

2. Check for DTCs.
   

   Result:

   Result	Proceed to
   DTC B1412 is not output	A
   DTC B1412 is output	B

1. Remove the ambient temperature sensor.
   

2. Disconnect the connector from the ambient temperature sensor.
   

3. 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:

   1. Hold the sensor only by its connector. Touching the sensor may change the resistance value.
      
   2. 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))