B1031

B1031-EVAPORATOR FIN TEMPERATURE SENSOR CIRCUIT LOW (ATC)





For a complete wiring diagram Refer to Diagrams/Electrical.

- When Monitored:

With the ignition on.

- Set Condition:

If the Evaporator Temperature Sensor input is out of range toward the low voltage threshold.





NOTE: This DTC must be active for the results of this test to be valid. Do not perform this test if this DTC is stored. Refer to HVAC System Test (ATC) for stored DTC test procedures. HVAC System Test (ATC)

Diagnostic Test

1.CHECK FOR DTC B1031-EVAPORATOR FIN TEMPERATURE SENSOR CIRCUIT LOW WITH EVAPORATOR TEMPERATURE SENSOR HARNESS CONNECTOR DISCONNECTED





Turn the ignition off.

Disconnect the Evaporator Temperature Sensor harness connector.

Turn the ignition on.

With the scan tool, erase HVAC DTCs.

Turn the ignition off, wait 10 seconds, and turn the ignition on.

With the scan tool, read HVAC DTCs.

Does the scan tool display: B1031-EVAPORATOR FIN TEMPERATURE SENSOR CIRCUIT LOW?

Yes

- Go To 2

No

- Replace the Evaporator Temperature Sensor.
- Perform BODY VERIFICATION TEST - VER 1. Body Verification Test

2.CHECK (C21) EVAPORATOR TEMPERATURE SENSOR SIGNAL CIRCUIT FOR A SHORT TO GROUND





Turn the ignition off.

Disconnect the A/C Heater Control C2 harness connector.

Measure the resistance of the (C21) Evaporator Temperature Sensor Signal circuit between ground and the A/C Heater Control C2 harness connector.

Is the resistance below 10k ohms?

Yes

- Repair the (C21) Evaporator Temperature Sensor Signal circuit for a short to ground.
- Perform BODY VERIFICATION TEST - VER 1. Body Verification Test

No

- Go To 3

3.CHECK (C21) EVAPORATOR TEMPERATURE SENSOR SIGNAL CIRCUIT FOR A SHORT TO (C121) SENSOR GROUND CIRCUIT





Measure the resistance between the (C21) Evaporator Temperature Sensor Signal circuit and the (C121) Sensor Ground circuit in the A/C Heater Control C2 harness connector.

Is the resistance below 10k ohms?

Yes

- Repair the (C21) Evaporator Temperature Sensor Signal circuit for a short to the (C121) Sensor Ground circuit.
- Perform BODY VERIFICATION TEST - VER 1. Body Verification Test

No

- Replace the A/C Heater Control.
- Perform BODY VERIFICATION TEST - VER 1. Body Verification Test