DTC B1231 or DTC indicator G and AUTO: An Open in the Evaporator Temperature Sensor Circuit
- Clear the DTC with the HDS.
- Turn the ignition switch to LOCK (0), and then to ON (II).
- Do the Self-Diagnostic Function with the HDS (see HOW TO USE THE SELF-DIAGNOSTIC FUNCTION WITH THE HDS ) or the climate control unit (see HOW TO USE THE SELF-DIAGNOSTIC FUNCTION WITHOUT THE HDS ).
- Check for DTCs.
Is DTC B1231 or G and AUTO indicated?
YES -Go to step 5.
NO -Intermittent failure. Check for loose wires or poor connections on the evaporator temperature sensor circuit.
- Turn the ignition switch to LOCK (0).
- Remove the evaporator temperature sensor (see EVAPORATOR CORE REPLACEMENT
), and test it (see EVAPORATOR TEMPERATURE SENSOR TEST
).
Is the evaporator temperature sensor OK?
YES -With the evaporator temperature sensor disconnected, go to step 7.
NO -Replace the evaporator temperature sensor (see EVAPORATOR CORE REPLACEMENT ).
- Disconnect the climate control unit 36P connector.
- Check for continuity between climate control unit 36P connector terminal No. 16 and evaporator temperature sensor 2P connector terminal No. 2.Fig 1: Checking Continuity Between Climate Control Unit 36P Connector Terminal No. 16 And Evaporator Temperature Sensor 2P Connector Terminal No. 2
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Is there continuity?
YES -Go to step 9.
NO -Repair an open in the wire between the climate control unit and the evaporator temperature sensor.
- Check for continuity between climate control unit 36P connector terminal No. 12 and evaporator temperature sensor 2P connector terminal No. 1.Fig 2: Checking Continuity Between Climate Control Unit 36P Connector Terminal No. 12 And Evaporator Temperature Sensor 2P Connector Terminal No. 1
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Is there continuity?
YES -Check for loose wires or poor connections at the climate control unit 36P connector and at the evaporator temperature sensor 2P connector, if the connections are good, substitute a known-good climate control unit, and recheck. If the symptom/indication goes away, replace the original climate control unit (see CLIMATE CONTROL UNIT REMOVAL/INSTALLATION ).
NO -Repair an open in the wire between the climate control unit and the evaporator temperature sensor.