MTC

B1031-EVAPORATOR FIN TEMPERATURE SENSOR CIRCUIT LOW (MTC)





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 the DTC is stored. Refer to HVAC System Test (ATC) for stored DTC test procedures. Heating-A/C System Diagnostics


Diagnostic Test


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 2


No


- Replace the Evaporator Temperature Sensor.
- Perform HVAC VERIFICATION TEST - VER 1.HVAC 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 (3 ZONE ATC) 32 way harness connector.
Measure the resistance between ground and the (C21) Evaporator Temperature Sensor Signal circuit in the A/C Heater Control (3 ZONE ATC) 32 way harness connector.
Is the resistance below 5 ohms?

Yes


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


No


- Go To 3


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




Measure the resistance between the (C21) Evaporator Temperature Sensor Signal circuit and the (C121) Sensor Ground circuit in the A/C Heater Control (3 ZONE ATC) 32 way harness connector.
Is the resistance below 5 ohms?

Yes


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


No


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