DTC B1B71:11, B1B71:13 [FULL-AUTO AIR CONDITIONER]

id0702c1817100

DTC B1B71:11

Evaporator temperature sensor circuit short to ground

DTC B1B71:13

Evaporator temperature sensor circuit open
POSSIBLE CAUSE
•  Evaporator temperature sensor malfunction
•  Open circuit in wiring harness between climate control unit connector terminal 1L and evaporator temperature sensor connector terminal B
•  Open circuit in wiring harness between climate control unit connector terminal 1E and evaporator temperature sensor connector terminal A
•  Short to ground in wiring harness between climate control unit connector terminal 1L and evaporator temperature sensor connector terminal B
•  Connector or terminal malfunction

Diagnostic procedure

STEP

INSPECTION

ACTION
1
INSPECT EVAPORATOR TEMPERATURE SENSOR CONNECTOR
•  Switch the ignition to off.
•  Disconnect the negative battery cable.
•  Disconnect the evaporator temperature sensor connector.
•  Inspect the connector and terminals (corrosion, damage, pin disconnection).
•  Are the connector and terminals normal?
Yes
Go to the next step.
No
Repair/replace the connector or terminal.
After repair procedure, go to the next step.
2
INSPECT EVAPORATOR TEMPERATURE SENSOR
•  Inspect the evaporator temperature sensor.
•  Is it normal?
Yes
Go to the next step.
No
Replace the evaporator temperature sensor.
(See A/C UNIT DISASSEMBLY/ASSEMBLY.)
Go to the next step.
3
INSPECT EVAPORATOR TEMPERATURE SENSOR CIRCUIT FOR OPEN CIRCUIT
•  Disconnect the climate control unit connector and the evaporator temperature sensor connector.
•  Is there an open circuit in the wiring harness between the following terminals of the climate control unit and the evaporator temperature sensor?
―  1E—A
―  1L—B
Yes
Repair the wiring harness.
Go to the next step.
No
Go to the next step.
4
INSPECT EVAPORATOR TEMPERATURE SENSOR CIRCUIT FOR SHORT TO GROUND
•  Is there a short circuit to ground in the wiring harness between climate control unit terminal 1L and evaporator temperature sensor terminal B?
Yes
Repair the wiring harness.
Go to the next step.
No
Connect the climate control unit connector, then go to the next step.
5
VERIFY CLIMATE CONTROL UNIT CONNECTOR CONDITION
•  Inspect the connector and terminals (corrosion, damage, pin disconnection).
•  Are the connector and terminals normal?
Yes
Go to the next step.
No
Repair/replace the malfunctioning vehicle wiring harness, connector, or terminal.
After repair procedure, go to the next step.
6
INSPECT EVAPORATOR TEMPERATURE SENSOR CIRCUIT
•  Connect the climate control unit connector.
•  Switch the ignition to ON.
•  Inspect the voltage at the following climate control unit terminal (wiring harness-side).
―  Terminal 1L (evaporator temperature sensor input signal)
•  Is the voltage normal? (Approx. 5 V)
Yes
The system is normal at present.
Go to the next step.
No
Go to the next step.
7
VERIFY THAT SAME DTC IS NOT OUTPUT AGAIN
•  Reconnect the disconnected connectors.
•  Clear the past malfunction from memory.
•  Verify DTCs.
•  Is DTC B1B71:11 or B1B71:13 output?
Yes
Repeat the inspection from Step 1.
•  If the malfunction does not recur, go to the next step.
•  If the malfunction recurs, replace the climate control unit.
Go to the next step.
No
Go to the next step.
8
VERIFY THAT NO OTHER DTCs ARE PRESENT
•  Verify other DTCs displayed.
•  Are any other DTCs output?
Yes
Perform the corresponding DTC inspection.
No
DTC troubleshooting completed.