Diagnostic Test

ACTIVE DTC
NOTE: Diagnose any CAN - C Communication DTCs before continuing.

NOTE: Make sure the A/C refrigerant system is properly charged in accordance with the Service Information.
1. Start the engine and allow it to reach normal operating temperature.
  WARNING: When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts or fan. Do not wear loose clothing. Failure to follow these instructions may result in possible serious or fatal injury.
  
  NOTE: Diagnose and repair any system voltage or sensor supply voltage DTCs before continuing with this test.
2. With the scan tool, select View DTCs.
  Is the DTC active at this time?
  
  Yes
  - Go to step 2
  No
  - Perform the INTERMITTENT CONDITION diagnostic procedure. Refer to DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure .
(T103) 5-VOLT SUPPLY CIRCUIT

Fig 1: Checking 5-Volt Supply Circuit
Courtesy of CHRYSLER LLC
1. Turn the ignition off.
2. Disconnect the A/C Pressure Transducer harness connector.
3. Ignition on, engine not running.
4. Measure the voltage on the (T103) 5-Volt supply circuit in the A/C Pressure Transducer harness connector.
  Is the voltage between 4.5 Volts to 5.2 Volts?
  
  Yes
  - Go to step 3
  No
  - Go to step 7
A/C PRESSURE TRANSDUCER
1. With the scan tool, monitor the A/C Pressure Transducer voltage.
  NOTE: The sensor voltage should be approximately 5.0 Volts (+/- 0.1 Volt) with the connector disconnected.
  
  Does the scan tool display the voltage as described above?
  
  Yes
  - Verify that there is good pin to terminal contact in the Transducer and Front Control Module connectors. If okay, replace the A/C Pressure Transducer.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure .
  No
  - Go to step 4
(C18) A/C PRESSURE SIGNAL CIRCUIT SHORTED TO GROUND

Fig 2: Measuring Resistance Between Ground And (C18) A/C Pressure Signal Circuit In A/C Pressure Transducer Harness Connector
Courtesy of CHRYSLER LLC
1. Turn the ignition off.
2. Disconnect the C1 FCM harness connector.
3. Measure the resistance between ground and the (C18) A/C Pressure Signal circuit in the A/C Pressure Transducer harness connector.
  Is the resistance below 100 Ohms?
  
  Yes
  - Repair the short to ground in the (C18) A/C Pressure Signal circuit.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure .
  No
  - Go to step 5
(C18) A/C PRESSURE SIGNAL CIRCUIT SHORTED TO THE (G180) SENSOR RETURN CIRCUIT

Fig 3: Measuring Resistance Between (C18) A/C Pressure Signal Circuit And (C918) Sensor Ground Circuit In A/C Pressure Transducer Harness Connector
Courtesy of CHRYSLER LLC
1. Disconnect the C3 FCM harness connector.
2. Measure the resistance between the (C18) A/C pressure signal circuit and the (G180) Sensor Return circuit in the A/C Pressure Transducer harness connector.
  Is the resistance below 100 Ohms?
  
  Yes
  - Repair the short between the (G180) Sensor Return circuit and the (C18) A/C Pressure Signal circuit.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure .
  No
  - Go to step 6
EXCESSIVE RESISTANCE IN THE (C18) A/C PRESSURE SIGNAL CIRCUIT

Fig 4: Measuring Resistance Of A/C Pressure Signal Circuit From A/C Pressure Transducer Harness Connector To FCM Harness Connector
Courtesy of CHRYSLER LLC
1. Measure the resistance of the (C18) A/C Pressure Signal circuit from the A/C Pressure Transducer harness connector to C1 FCM harness connector.
  Is the resistance below 5.0 Ohms?
  
  Yes
  - Go to step 9
  No
  - Repair the excessive resistance in the (C18) A/C Pressure Signal circuit.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure .
(T103) 5-VOLT SUPPLY CIRCUIT OPEN

Fig 5: Checking 5-Volt Supply Circuit
Courtesy of CHRYSLER LLC
1. Turn the ignition off.
2. Disconnect the C1 FCM harness connector.
3. Measure the resistance of the (T103) 5-Volt Supply circuit from the A/C Pressure Transducer harness connector to the C1 FCM harness connector.
  Is the resistance below 5.0 Ohms?
  
  Yes
  - Go to step 8
  No
  - Repair the open in the (T103) 5-Volt Supply circuit.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure .
(T103) 5-VOLT SUPPLY CIRCUIT SHORTED TO GROUND

Fig 6: Checking 5-Volt Supply Circuit
Courtesy of CHRYSLER LLC
1. Measure the resistance between ground and the (T103) 5-Volt Supply circuit in the A/C Pressure Transducer harness connector.
  Is the resistance below 100 Ohms?
  
  Yes
  - Repair the short to ground in the (T103) 5-Volt Supply circuit.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure .
  No
  - Go to step 9
FRONT CONTROL MODULE (FCM)
1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the A/C Pressure Transducer and the Front Control Module (FCM).
2. Look for any chafed, pierced, pinched, or partially broken wires.
3. Look for broken, bent, pushed out or corroded terminals. Verify that there is good pin to terminal contact in the Transducer and Front Control Module connectors.
4. Refer to any Technical Service Bulletins that may apply.
  Were there any problems found?
  
  Yes
  - Repair as necessary.
  - Perform BODY VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Front Control (FCM) - Standard Procedure .
  No
  - Replace and program the Front Control Module in accordance with the Service Information.
  - Perform BODY VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Front Control (FCM) - Standard Procedure .