DTC B1412/12: Ambient Temperature Sensor Circuit [10/2014 - ]: Procedure

1. Connect the Techstream to the DLC3.
2. Turn the power switch on (IG).
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	Thermistor assembly / Min: -23.30°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

Result: 

B 

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE 

(Refer to PROBLEM SYMPTOMS TABLE [10/2014 - 10/2015] or PROBLEM SYMPTOMS TABLE [10/2015 - ] )

Result: 

C 

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY 

(Refer to REMOVAL [10/2014 - ] )

Result: 

A 

See step  2

1. Remove the thermistor assembly (Refer to REMOVAL [10/2014 - ] ).

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

2. 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
   1 (-) - 2 (+)	15°C (59°F)	2.45 to 2.88 kΩ
   1 (-) - 2 (+)	20°C (68°F)	1.95 to 2.30 kΩ
   1 (-) - 2 (+)	25°C (77°F)	1.60 to 1.80 kΩ
   1 (-) - 2 (+)	30°C (86°F)	1.28 to 1.47 kΩ
   1 (-) - 2 (+)	35°C (95°F)	1.00 to 1.22 kΩ
   1 (-) - 2 (+)	40°C (104°F)	0.80 to 1.00 kΩ
   1 (-) - 2 (+)	45°C (113°F)	0.65 to 0.85 kΩ
   1 (-) - 2 (+)	50°C (122°F)	0.50 to 0.70 kΩ
   1 (-) - 2 (+)	55°C (131°F)	0.44 to 0.60 kΩ
   1 (-) - 2 (+)	60°C (140°F)	0.36 to 0.50 kΩ

   NOTE:

   • Hold the sensor only by its connector. Touching the sensing portion 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 (Thermistor Assembly)
   *b	Sensing Portion
   *c	Resistance (kΩ)
   *d	Allowable Range
   *e	Temperature (°C (°F))

Result: 

NG 

REPLACE THERMISTOR ASSEMBLY 

(Refer to REMOVAL [10/2014 - ] )

Result: 

OK 

See step  3

1. Disconnect the D62 air conditioning amplifier assembly connector.
2. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   D62-5 (TAM) - A3-2 (+)	Always	Below 1 Ω
   D62-13 (SG-2) - A3-1 (-)	Always	Below 1 Ω
   D62-5 (TAM) - Body ground	Always	10 kΩ or higher
   D62-13 (SG-2) - Body ground	Always	10 kΩ or higher

Result: 

OK 

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY 

(Refer to REMOVAL [10/2014 - ] )

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR