Inspection Procedure

1. Connect the intelligent tester (with CAN VIM) to DLC3.
2. Turn the power switch ON (IG) and push the intelligent tester main switch ON.
3. Select the item below in the DATA LIST, and read the display on the intelligent tester.

   Air conditioning amplifier 

   DATA LIST
   
   

   Item	Measurement Item / Display (Range)	Normal Condition	Diagnostic Note
   ROOM TEMP	Room temperature sensor / Open in the circuit: min.: -6.5°C (20.3°F) max.: 57.25°C (135.05°F)	Actual room temperature is displayed	Open in the circuit: -6.5°C (20.3°F) Short in the circuit: 57.25°C (135.05°F)

   OK : The display is as specified in the normal condition. 

   Result 

   RESULT REFERENCE
   
   

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

B : PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN  PROBLEM SYMPTOMS TABLE  

C : REPLACE AIR CONDITIONING AMPLIFIER 

A : Go to next step 

1. Remove the air conditioning amplifier with connectors still connected.
2. Measure the voltage of the wire harness side connector.

   Standard voltage 

   TERMINALS VOLTAGE SPECIFICATIONS
   
   

   Tester Connection	Condition	Specified Condition
   A7-8 (TR) - A7-22 (SGTR)	Power switch ON (IG) at 25°C (77°F)	1.8 to 2.2 V
   A7-8 (TR) - A7-22 (SGTR)	Power switch ON (IG) at 40°C (104°F)	1.2 to 1.6 V

   Fig 1: Identifying Air Conditioning Amplifier Connectors

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   HINT:

   As the temperature increases, the voltage decreases.

   Result 

   RESULT REFERENCE
   
   

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

B : PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN  PROBLEM SYMPTOMS TABLE  

C : REPLACE AIR CONDITIONING AMPLIFIER 

A : Go to next step 

1. Remove the room temperature sensor.
2. Measure the resistance of the sensor.

   Standard resistance 

   TERMINALS RESISTANCE SPECIFICATIONS
   
   

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

   NOTE:

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

   HINT:

   As the temperature increases, the resistance decreases (see the graph).

NG : REPLACE ROOM TEMPERATURE SENSOR 

Fig 2: Room Temperature Sensor Resistance Graph

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

OK : GO TO NEXT STEP 

1. Disconnect the A9 sensor connector.
2. Disconnect the A7 amplifier connector.
3. Measure the resistance of the wire harness side connectors.

   Standard resistance 

   TERMINALS RESISTANCE SPECIFICATIONS
   
   

   Tester Connection	Specified Condition
   A7-8 (TR) - A9-1 (THR)	Below 1 Ω
   A7-22 (SGTR) - A9-2 (GND)	Below 1 Ω
   A7-8 (TR) - Body ground	10 kΩ or higher
   A7-22 (SGTR) - Body ground	10 kΩ or higher

NG : REPAIR OR REPLACE HARNESS AND CONNECTOR 

Fig 3: Identifying Room Temperature Sensor And Air Conditioning Amplifier Connectors

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

OK : REPLACE AIR CONDITIONING AMPLIFIER