HEATING / AIR CONDITIONING AIR CONDITIONING SYSTEM(for Automatic Air Conditioning System) B1419 Rear Room Temperature Sensor Circuit
DESCRIPTION
The cooler thermistor (No. 2 room temperature sensor) is installed in the deck trim side panel to detect the cabin temperature which is used to control the heater and air conditioning system AUTO mode. The resistance of the cooler thermistor (No. 2 room temperature sensor) changes in accordance with the cabin temperature. As the temperature decreases, the resistance increases. As the temperature increases, the resistance decreases.
The air conditioning amplifier assembly applies a voltage (5 V) to the cooler thermistor (No. 2 room temperature sensor) and reads voltage changes due to changes in the resistance of the cooler thermistor (No. 2 room temperature sensor).
| DTC No. | Detection Item | DTC Detection Condition | Trouble Area | Memory |
|---|---|---|---|---|
| B1419/19 | Rear Room Temperature Sensor Circuit | ·
Diagnosis condition: Ambient temperature is -30°C (-22°F) or more ·
Malfunction status: Open or short in room temperature sensor circuit ·
Detection time: None (Present malfunction), continuously for 4 seconds or more (Past malfunction) |
·
Cooler thermistor (No. 2 room temperature sensor) ·
Harness or connector ·
Air conditioning amplifier assembly |
Memorized (4 seconds or more) |
- HINT:
-
If the cabin temperature is approximately -18.6°C (-1.48°F) or lower, DTC B1419 may be output even though the system is normal.
WIRING DIAGRAM
PROCEDURE
Connect the GTS to the DLC3.
Turn the engine switch on (IG).
Turn the GTS on.
Enter the following menus: Body Electrical / Air Conditioner / Data List.
Check the value(s) by referring to the table below.
- Body Electrical > Air Conditioner > Data List
-
Tester Display Measurement Item Range Normal Condition Diagnostic Note Room Temp Sensor (Rear) Cooler thermistor (No. 2 room temperature sensor) Min.: -6.50°C (-20.30°F)
Max.: 57.25°C (135.05°F)Actual ambient temperature displayed Cooler thermistor (No. 2 room temperature sensor) system malfunction:
·When open circuit: -6.50°C (-20.30°F)
·When short circuit: 57.25°C (135.05°F)
- Body Electrical > Air Conditioner > Data List
-
Tester Display Room Temp Sensor (Rear) - 50003 121 54
- OK:
The display is as specified in the normal condition column.
- Result:
Proceed to OK NG
OK
NG
Remove the cooler thermistor (No. 2 room temperature sensor).
Inspect the cooler thermistor (No. 2 room temperature sensor).
- Result:
Proceed to OK NG
OK
NG
Disconnect the W29 cooler thermistor (No. 2 room temperature sensor) connector.
Disconnect the N79 air conditioning amplifier assembly connector.
Measure the resistance according to the value(s) in the table below.
- Standard Resistance:
Tester Connection Condition Specified Condition W29-2 - N79-14 (SG-6) Always Below 1 Ω W29-1 - N79-8 (TR) Always Below 1 Ω W29-2 or N79-14 (SG-6) - Other terminals and body ground Always 10 kΩ or higher W29-1 or N79-8 (TR) - Other terminals and body ground Always 10 kΩ or higher
- Result:
Proceed to OK NG
OK
NG