Manual Temperature Control

B1031 - Evaporator Fin Temperature Sensor Circuit Low






For a complete wiring diagram, refer to.

• When Monitored: With the ignition on.

• Set Condition: If the evaporator temperature sensor input is out of range toward the low voltage threshold.






• This DTC must be active for the results of this test to be valid. Do not perform this test if this DTC is stored.

Test Step 1 - Check for DTC with The 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 this DTC as active?

Yes

• Go to Test Step 2 => [ Test Step 2 - Check Evaporator Temperature Sensor Signal Circuit
for a Short to Ground ]

No

• Replace the evaporator temperature sensor.

• Perform the HVAC Verification Test. Refer to => Non-DTC Based Diagnostics. HVAC Verification Test

Test Step 2 - Check Evaporator Temperature Sensor Signal Circuit for a Short to Ground






• Turn the ignition OFF.

• Disconnect the A/C heater control (3 ZONE ATC) 32 way harness connector.

• Measure the resistance between ground and the evaporator temperature sensor signal circuit in the A/C heater control (3 ZONE ATC) 32 way harness connector.

Is the resistance less than 5 ohms?

Yes

• Repair the evaporator temperature sensor signal circuit for a short to ground.

• Perform the HVAC Verification Test. Refer to => Non-DTC Based Diagnostics. HVAC Verification Test

No

• Go to Test Step 3 => [ Test Step 3 - Check Evaporator Temperature Sensor Signal Circuit
for a Short to Sensor Ground ]

Test Step 3 - Check Evaporator Temperature Sensor Signal Circuit for a Short to Sensor Ground






• Measure the resistance between the evaporator temperature sensor signal circuit and the sensor ground circuit in the A/C heater control (3 ZONE ATC) 32 way harness connector.

Is the resistance less than 5 ohms?

Yes

• Repair the evaporator temperature sensor signal circuit for a short to the sensor ground circuit.

• Perform the HVAC Verification Test. Refer to => Non-DTC Based Diagnostics. HVAC Verification Test

No

• Replace the A/C heater control.

• Perform the HVAC Verification Test. Refer to => Non-DTC Based Diagnostics. HVAC Verification Test