Inspection Procedure

1. Check the difference in ambient temperature between the value displayed on the clock assy and the actual temperature.

   OK: 

   The ambient temperature displayed on the clock assy and the actual ambient temperature are almost the same. 

Fig 1: Identifying Temperature Value On Clock Assy

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HINT:

The temperature displayed on the clock assy and the actual temperature detected by the sensor may differ when the ambient temperature rises significantly (such as when the vehicle stops immediately after start-up).

1. NG: Go to step   2 
2. OK: Go to step   5 

1. Remove the clock assy with the connector still connected.
2. Turn the ignition switch to the ON position.
3. Measure the voltage according to the value(s) in CLOCK ASSY (TH+ - SG) VOLTAGE  .

   Standard: 

   CLOCK ASSY (TH+ - SG) VOLTAGE
   
   

   Tester connection	Condition	Specified condition
   C5-3 (TH+) - C5-2 (SG)	Ignition switch ON at 25°C (77°F)	1.8 to 2.2 V
   C5-3 (TH+) - C5-2 (SG)	Ignition switch ON at 40°C (104°F)	1.2 to 1.6 V
   C5-13 (DATA) - Body ground	Each temperature	Pulse generation

   Fig 2: Identifying Terminals Of Clock Assy Connector

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

HINT:

As the temperature increases, the voltage decreases.

Result: 

1. B: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE (SEE  TERMINALS OF ECU  ) 
2. C: Go to step   5 
3. A: Go to Next Step. 

1. Remove the A/C ambient temperature sensor (cooler (ambient temp. sensor) thermistor).
2. Measure the resistance according to the value(s) in A/C AMBIENT TEMPERATURE SENSOR RESISTANCE  .

   Standard: 

   A/C AMBIENT TEMPERATURE SENSOR RESISTANCE
   
   

   Tester connection	Condition	Specified condition
   A1-1 - A1-2	10°C (50°F)	3.00 to 3.73 kΩ
   A1-1 - A1-2	15°C (59°F)	2.45 to 2.88 kΩ
   A1-1 - A1-2	20°C (68°F)	1.95 to 2.30 kΩ
   A1-1 - A1-2	25°C (77°F)	1.60 to 1.80 kΩ
   A1-1 - A1-2	30°C (86°F)	1.28 to 1.47 kΩ
   A1-1 - A1-2	35°C (95°F)	1.00 to 1.22 kΩ
   A1-1 - A1-2	40°C (104°F)	0.80 to 1.00 kΩ
   A1-1 - A1-2	45°C (113°F)	0.65 to 0.85 kΩ
   A1-1 - A1-2	50°C (122°F)	0.50 to 0.70 kΩ
   A1-1 - A1-2	55°C (131°F)	0.44 to 0.60 kΩ
   A1-1 - A1-2	60°C (140°F)	0.36 to 0.50 kΩ

   Fig 3: Identifying Terminals Of A/C Ambient Temperature Sensor

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

HINT:

As the temperature increases, the resistance decreases (see Fig 4 ).

Fig 4: Resistance Temperature Graph

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1. NG: REPLACE A/C AMBIENT TEMPERATURE SENSOR (COOLER (AMBIENT TEMP. SENSOR) THERMISTOR) 
2. OK: Go to Next Step. 

1. Measure the resistance according to the value(s) in Fig 6 .

   Standard: 

   Fig 5: Checking Harness & Connector (Clock Assy - A/C Ambient Temperature Sensor (Cooler (Ambient Temp. Sensor) Thermistor) (1 Of 2)

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002