Diagnostic Test

WARNING: This page is about a different car, the 2016 Jeep Wrangler and 2015 Jeep Wrangler. However, it is still accessible from the selected car via links, so may be relevant.

CHECK IF THE DTC IS ACTIVE
1. Ignition on, engine not running.
2. Using the scan tool, read HVAC DTCs.
  Is this DTC active?
  
  Yes
  - Go To 2
  No
  - Go To 5
CHECK (C21) EVAPORATOR TEMPERATURE SENSOR SIGNAL CIRCUIT FOR A SHORT TO GROUND

Fig 1: Checking Evaporator Temperature Sensor Signal Circuit For A Short To Ground
Courtesy of CHRYSLER GROUP, LLC
1. Turn the ignition off to the lock position.
2. Disconnect the A/C Heater Control C1 harness connector.
3. Disconnect the Evaporator Temperature Sensor harness connector.
4. Measure the resistance between ground and the (C21) Evaporator Temperature Sensor Signal circuit.
  Is the resistance below 100k Ohms?
  
  Yes
  - Repair the (C21) Evaporator Temperature Sensor Signal circuit for a short to ground.
  - Perform the HVAC VERIFICATION TEST. Refer to STANDARD PROCEDURE .
  No
  - Go To 3
CHECK (C21) EVAPORATOR TEMPERATURE SENSOR SIGNAL CIRCUIT FOR A SHORT TO THE (C121) SENSOR GROUND CIRCUIT

Fig 2: Measuring Resistance Between Evaporator Temperature Sensor Signal Circuit & Sensor Ground Circuit
Courtesy of CHRYSLER GROUP, LLC
1. Measure the resistance between the (C21) Evaporator Temperature Sensor Signal circuit and the (C121) Sensor Ground circuit.
  Is the resistance below 100k Ohms?
  
  Yes
  - Repair the (C21) Evaporator Temperature Sensor Signal circuit for a short to (C121) Sensor Ground circuit.
  - Perform the HVAC VERIFICATION TEST. Refer to STANDARD PROCEDURE .
  No
  - Go To 4
CHECK THE EVAPORATOR TEMPERATURE SENSOR
1. Replace the Evaporator Temperature Sensor in accordance with the Service Information. Refer to SENSOR, EVAPORATOR TEMPERATURE, REMOVAL .
2. Cycle the ignition off for 30 seconds then back on.
3. With the scan tool, read HVAC DTCs.
  Does this DTC reset?
  
  Yes
  - Replace and program the A/C Heater Control in accordance with the Service Information. Refer to CONTROL, A/C AND HEATER, REMOVAL .
  - Perform the HVAC VERIFICATION TEST. Refer to STANDARD PROCEDURE .
  No
  - Test complete.
  - Perform the HVAC VERIFICATION TEST. Refer to STANDARD PROCEDURE .
CHECK THE WIRING AND CONNECTORS
1. The conditions necessary to set the DTC are not present at this time.
2. Using the scan tool, check the Environmental Data to help identify the conditions in which the DTC was set.
3. Using the wiring diagrams as a guide, check all related splices and connectors for signs of water intrusion, corrosion, pushed out or bent terminals, and correct pin tension.
4. Wiggle the wiring and connectors while checking for shorted and open circuits.
  Were there any problems found?
  
  Yes
  - Repair as necessary.
  - Perform the HVAC VERIFICATION TEST. Refer to STANDARD PROCEDURE .
  No
  - Test complete.