Diagnostic Test

CHECK FOR ACTIVE DTC
1. Turn the ignition on.
2. With the scan tool, read the active DTCs.
  Does the scan tool display this DTC as active?
  
  Yes
  - Go to step 2
  No
  - If the DTC is stored, check for an intermittent condition. Visually inspect the related wiring harness connectors. Look for broken, bent, pushed out, or corroded terminals.
  - Perform the BODY VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Front Control (FCM) - Standard Procedure .
A/C PRESSURE TRANSDUCER

Fig 1: Checking A/C Pressure Transducer
Courtesy of CHRYSLER LLC
1. Turn the ignition off.
2. Disconnect the A/C Pressure Transducer harness connector.
3. Turn the ignition on.
4. Measure the voltage across the (F981) 5 Volt Supply circuit and the (C918) FCM Sensor Return circuit at the A/C Pressure Transducer harness connector.
  Does the voltage read 5.0 Volts?
  
  Yes
  - Replace the A/C Pressure Transducer in accordance with the service information.
  - Perform the BODY VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Front Control (FCM) - Standard Procedure .
  No
  - Go to step 3
(F891) 5 VOLT SUPPLY CIRCUIT SHORTED TO VOLTAGE

Fig 2: Checking 5 Volt Supply Circuit Shorted To Voltage
Courtesy of CHRYSLER LLC
1. Turn the ignition off.
2. Disconnect the FCM C1 harness connector.
3. Turn the ignition on.
4. Measure the voltage of the (F891) 5 Volt Supply circuit.
  Is the voltage above 5.5 volts?
  
  Yes
  - Repair the (F891) 5 Volt Supply circuit for a short to voltage.
  - Perform the BODY VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Front Control (FCM) - Standard Procedure .
  No
  - Go to step 4
(F891) 5 VOLT SUPPLY CIRCUIT OPEN

Fig 3: Checking 5 Volt Supply Circuit Open
Courtesy of CHRYSLER LLC
1. Turn the ignition off.
2. Measure the resistance of the (F981) 5 Volt Supply circuit.
  Is the resistance above 10.0 Ohms?
  
  Yes
  - Repair the (F891) 5 Volt Supply circuit for an open.
  - Perform the BODY VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Front Control (FCM) - Standard Procedure .
  No
  - Go to step 5
(F891) 5 VOLT SUPPLY CIRCUIT SHORTED TO THE (C18) A/C PRESSURE SIGNAL CIRCUIT

Fig 4: Checking 5 Volt Supply Circuit Shorted To A/C Pressure Signal Circuit
Courtesy of CHRYSLER LLC
1. Measure the resistance between the (F981) 5 Volt Supply circuit and the (C18) A/C Pressure Signal circuit.
  Is the resistance below 10.0 Ohms?
  
  Yes
  - Repair the (F891) 5 Volt Supply circuit for a short to the (C18) A/C Pressure Signal circuit.
  - Perform the BODY VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Front Control (FCM) - Standard Procedure .
  No
  - Go to step 6
(C918) FCM SENSOR RETURN CIRCUIT OPEN

Fig 5: Checking Front Control Module Sensor Return Circuit Open
Courtesy of CHRYSLER LLC
1. Disconnect the IPM C1 harness connector.
2. Measure the resistance of the (C918) FCM Sensor Return circuit.
  Is the resistance above 10.0 Ohms?
  
  Yes
  - Repair the (C918) FCM Sensor Return circuit for an open.
  - Perform the BODY VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Front Control (FCM) - Standard Procedure .
  No
  - Go to step 7
INTEGRATED POWER MODULE (IPM) / FRONT CONTROL MODULE (FCM)
1. Reconnect the IPM C1 harness connector.
2. Remove the FCM from the IPM.
3. Measure the resistance of the (C918) FCM Sensor Return circuit between the A/C Pressure Transducer harness connector and the IPM Terminal 35.
  Is the resistance above 10.0 Ohms?
  
  Yes
  - Replace the IPM in accordance with the Service Information.
  - Perform the BODY VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Front Control (FCM) - Standard Procedure .
  No
  - Replace the FCM in accordance with the Service Information.
  - Perform the BODY VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Front Control (FCM) - Standard Procedure .