DESCRIPTION
The thermistor assembly 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 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 and reads voltage changes due to changes in the resistance of the thermistor assembly.
NOTICE:
The thermistor assembly 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 and not the ambient temperature of the air surrounding the vehicle). Therefore, the ambient temperature around the thermistor assembly 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:
Click here
Turn the ignition switch ON. (Do not start the engine.)
PROCEDURE
1. |
CHECK FOR DTC |
(a) Clear the DTC.
Click here
Body Electrical > Air Conditioner > Clear DTCs(b) Check for DTCs when the following conditions are met.
Click here
Body Electrical > Air Conditioner > Trouble CodesNOTICE:
During the parked vehicle inspection, perform the inspection with the ignition switch ON (do not start the engine).
Result |
Proceed to |
---|---|
DTC B1412 is not output |
A |
DTC B1412 is output |
B |
B |
GO TO DTC B1412 |
|
2. |
INSPECT THERMISTOR ASSEMBLY |
(a) Remove the thermistor assembly.
Click here
(b) Inspect the thermistor assembly.
Click here
NG |
REPLACE THERMISTOR ASSEMBLY |
|
3. |
CHECK HARNESS AND CONNECTOR (THERMISTOR ASSEMBLY - COMBINATION METER ASSEMBLY) |
NOTICE:
During the parked vehicle inspection, perform the inspection with the ignition switch off (do not start the engine).
(a) Disconnect the A3 thermistor assembly connector.
(b) Disconnect the F4 combination meter assembly connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Tester Connection |
Condition |
Specified Condition |
---|---|---|
A3-2 - F4-34 (TEMP) |
Always |
Below 1 Ω |
A3-1 - F4-35 (TX1+) |
Always |
Below 1 Ω |
A3-1 - A3-2 |
Always |
10 kΩ or higher |
A3-2 or F4-34 (TEMP) - Body ground |
Always |
10 kΩ or higher |
A3-1 or F4-35 (TX1+) - Body ground |
Always |
10 kΩ or higher |
NG |
REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
4. |
CHECK AMBIENT TEMPERATURE COMPARISON |
(a) Disconnect the cable from the negative (-) battery terminal.
NOTICE:
Make sure the wire harness(es) and connector(s) for the vehicle being inspected are connected. After the ignition 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 (-) battery terminal after confirming that 6 minutes or more have elapsed since turning the ignition switch off.
(b) Disconnect the cable from the negative (-) battery terminal and wait 90 seconds or more.
HINT:
The air conditioning amplifier assembly reads and memorizes the thermistor assembly detection value from before the ignition switch was turned off for 1 hour after turning the ignition 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 ignition switch was turned off.
(c) Connect the cable to the negative (-) battery terminal.
(d) Using a thermometer, measure the ambient temperature of the installation area around the thermistor assembly 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 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 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 |
Toyota CH-R Service Manual > Audio And Visual System(for Radio And Display Type): Reverse Signal Circuit
DESCRIPTION
The radio and display receiver assembly receives a reverse signal from the park/neutral
position switch.
WIRING DIAGRAM
PROCEDURE
1.
CHECK BACK-UP LIGHT
(a) Move the shift lever to R and check if the back-up lights come on.
OK:
The back-up ligh ...
Toyota CH-R Service Manual > Vehicle Stability Control System: Open or Short in Brake Pedal Load Sensing Switch (C1429)
DESCRIPTION
The brake pedal load sensing switch turns on when the brake pedal is depressed
with a force exceeding a predetermined level.
The skid control ECU uses this circuit to detect if the brake pedal is depressed
or not.
DTC No.
Detection Item
DTC Detecti ...