DESCRIPTION
The thermistor assembly (ambient temperature sensor) is installed in front of the cooler condenser assembly to detect the ambient temperature which is used to control the air conditioning system AUTO mode. This sensor is connected to the air conditioning amplifier assembly and detects fluctuations in the ambient temperature. This data is used for controlling the cabin temperature. The sensor sends a signal to the air conditioning amplifier assembly. The resistance of the thermistor assembly (ambient temperature sensor) changes in accordance with the ambient temperature. As the temperature decreases, the resistance increases. Conversely, as the temperature increases, the resistance decreases.
The air conditioning amplifier assembly applies a voltage (5 V) to the thermistor assembly (ambient temperature sensor) and reads voltage changes due to changes in the resistance of the thermistor assembly (ambient temperature sensor).
NOTICE:
The thermistor assembly (ambient temperature sensor) is installed on the front of the cooler condenser assembly in the engine room and detects the ambient temperature around the installation area (the ambient temperature detected is the temperature detected around the thermistor assembly (ambient temperature sensor) and not the ambient temperature of the air surrounding the vehicle). Therefore, the ambient temperature around the thermistor assembly (ambient temperature sensor) changes depending on the radiated heat from the engine room and the ambient temperature display value is affected by vehicle speed. In the following cases, the ambient temperature of the air surrounding the vehicle and the displayed value are different and the speed at which the displayed value updates is delayed. However, this is not a malfunction.
WIRING DIAGRAM
CAUTION / NOTICE / HINT
NOTICE:
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HINT:
When disconnecting and reconnecting the auxiliary battery, there is an automatic learning function that completes learning when the respective system is used.
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Turn the power switch on (IG). (Do not start the engine and electric motor.)
PROCEDURE
1. | CHECK FOR DTC |
(a) Clear the DTC.
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Body Electrical > Air Conditioner > Clear DTCs(b) Check for DTCs when the following conditions are met.
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Body Electrical > Air Conditioner > Trouble CodesNOTICE:
During the parked vehicle inspection, perform the inspection with the power switch on (IG) (do not start the engine and electric motor).
Result | Proceed to |
---|---|
DTC B1412 is not output | A |
DTC B1412 is output | B |
B | GO TO DTC B1412 |
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2. | INSPECT THERMISTOR ASSEMBLY (AMBIENT TEMPERATURE SENSOR) |
NOTICE:
During the parked vehicle inspection, perform the inspection with the power switch off (do not start the engine and electric motor).
(a) Disconnect the thermistor assembly (ambient temperature sensor) connector.
(b) Measure the resistance according to the value(s) in the table below. Standard Resistance:
NOTICE:
HINT: As the temperature increases, the resistance decreases (see the graph). |
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NG | REPLACE THERMISTOR ASSEMBLY (AMBIENT TEMPERATURE SENSOR) |
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3. | CHECK HARNESS AND CONNECTOR (THERMISTOR ASSEMBLY [AMBIENT TEMPERATURE SENSOR] - AIR CONDITIONING AMPLIFIER ASSEMBLY) |
NOTICE:
During the parked vehicle inspection, perform the inspection with the power switch off (do not start the engine and electric motor).
(a) Disconnect the A16 thermistor assembly (ambient temperature sensor) connector.
(b) Disconnect the I50 air conditioning amplifier assembly connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Tester Connection | Condition | Specified Condition |
---|---|---|
A16-2 - I50-5 (TAM) | Always | Below 1 Ω |
A16-1 - I50-13 (SG-2) | Always | Below 1 Ω |
A16-2 - A16-1 | Always | 10 kΩ or higher |
A16-2 or I50-5 (TAM) - Body ground | Always | 10 kΩ or higher |
A16-1 or I50-13 (SG-2) - Body ground | Always | 10 kΩ or higher |
NG | REPAIR OR REPLACE HARNESS OR CONNECTOR |
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4. | CHECK AMBIENT TEMPERATURE COMPARISON |
(a) Disconnect the cable from the negative (-) auxiliary battery terminal.
NOTICE:
Make sure the wire harness(es) and connector(s) for the vehicle being inspected are connected. After the power switch is turned off, the navigation system stores the various memory and settings within approximately 6 minutes. Therefore, make sure to disconnect the cable from the negative (-) auxiliary battery terminal after confirming that 6 minutes or more have elapsed since turning the power switch off.
(b) Disconnect the cable from the negative (-) auxiliary battery terminal and wait 90 seconds or more.
HINT:
The air conditioning amplifier assembly reads and memorizes the thermistor assembly (ambient temperature sensor) detection value (THO) from before the power switch was turned off for 1 hour after turning the power switch off. Therefore, it is necessary to switch off the air conditioning amplifier assembly internal power source and clear the stored values from before the power switch was turned off.
(c) Connect the cable to the negative (-) auxiliary battery terminal.
(d) Using a thermometer, measure the ambient temperature of the installation area around the thermistor assembly (ambient temperature sensor) and record it.
NOTICE:
(e) Record the ambient temperature value displayed on the multi-information display of the combination meter assembly.
(f) Compare the ambient temperature of the installation area around the thermistor assembly (ambient temperature sensor) with the ambient temperature value displayed on the multi-information display of the combination meter assembly.
Standard:
The ambient temperature of the installation area around the thermistor assembly (ambient temperature sensor) is approximately the same as the ambient temperature value displayed on the multi-information display of the combination meter assembly.
OK | END |
NG | REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY |