Dtc 12 Ambient Temperature Sensor Circuit

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

CHECK ACCESSORY METER ASSEMBLY

CHECK HARNESS AND CONNECTOR (ACCESSORY METER - AIR CONDITIONING AMPLIFIER)

CHECK ACCESSORY METER ASSEMBLY (TH+, DATA VOLTAGE)

CHECK HARNESS AND CONNECTOR (ACCESSORY METER - AIR CONDITIONING AMPLIFIER)

INSPECT THERMISTOR ASSEMBLY (A/C AMBIENT TEMPERATURE SENSOR)

CHECK HARNESS AND CONNECTOR (THERMISTOR - ACCESSORY METER)

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

1. Check the difference between the ambient temperature value displayed on the accessory meter and the actual ambient temperature.
   

   OK:

   The ambient temperature displayed on the accessory meter and the actual ambient temperature are almost the same.
   

   HINT:

   The temperature displayed on the accessory meter and the actual temperature detected by the thermistor may differ when the ambient temperature changes significantly (for example, when the vehicle is entering/exiting tunnels, or the vehicle speed or wind direction changes).

1. Disconnect the A23 meter connector.
   

2. Disconnect the A16 amplifier connector.
   

3. Measure the resistance according to the value(s) in the table below.
   

   Standard Resistance:

   Tester Connection	Condition	Specified Condition
   A23-9 (DATA) - A16-18 (TAMO)	Always	Below 1 Ω
   A23-9 (DATA) - Body ground	Always	10 kΩ or higher

1. Remove the accessory meter with its connectors still connected.
   

2. Measure the voltage according to the value(s) in the table below.
   

   Standard Voltage:

   Tester Connection	Switch Condition	Specified Condition
   A23-3 (TH+) - A23-2 (SG)	Ignition switch ON Ambient temperature: 20 to 30°C (68 to 86°F)	1.0 to 1.6 V
   	Ignition switch ON Ambient temperature: 30 to 50°C (86 to 122°F)	0.6 to 1.0 V
   A23-9 (DATA) - Body ground	Ignition switch ON Ambient temperature changes	Pulse generation

   HINT:

   As the temperature increases, the voltage decreases.

   Result

   Result	Proceed to
   OK (Checking from the PROBLEM SYMPTOMS TABLE)	A
   OK (Checking from the DTC)	B
   NG	C

1. Disconnect the A23 meter connector.
   

2. Disconnect the A16 amplifier connector.
   

3. Measure the resistance according to the value(s) in the table below.
   

   Standard Resistance:

   Tester Connection	Condition	Specified Condition
   A23-9 (DATA) - A16-18 (TAMO)	Always	Below 1 Ω
   A23-9 (DATA) - Body ground	Always	10 kΩ or higher

1. Remove the thermistor.
   

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
   	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:

   1. Even slightly touching the thermistor may change the resistance value. Be sure to hold the connector of the thermistor.
      
   2. When measuring the resistance, the thermistor temperature must be the same as the ambient temperature.
      

   HINT:

   As the temperature increases, the resistance decreases (Refer to the graph).

1. Disconnect the A1 thermistor connector.
   

2. Disconnect the A23 meter connector.
   

3. Measure the resistance according to the value(s) in the table below.
   

   Standard Resistance:

   Tester Connection	Condition	Specified Condition
   A23-3 (TH+) - A1-2	Always	Below 1 Ω
   A23-2 (SG) - A1-1
   A23-3 (TH+) - Body ground	Always	10 kΩ or higher
   A23-2 (SG) - Body ground