Diagnostic Test

WARNING: This page is about a different car, the 2013 RAM 2500 HD and 2012 RAM Pickup. However, it is still accessible from the selected car via links, so may be relevant.

ACTIVE DTC
NOTE:
Diagnose and repair any communication, system voltage or sensor supply voltage 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.
2. With the scan tool, select View DTCs.
  Is the DTC Active at this time?
  
  Yes
  - Go To 2
  No
  - Perform the INTERMITTENT CONDITION diagnostic procedure. Refer to STANDARD PROCEDURE .
CHECK THE (F855) 5-VOLT SUPPLY CIRCUIT
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 (F855) 5-Volt Supply circuit at the A/C Pressure Transducer harness connector.
  Is the voltage between 4.8 and 5.2 volts?
  
  Yes
  - Go To 3
  No
  - Go To 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 (plus or minus 1 volts) 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 A/C Pressure Transducer and the Powertrain Control Module connectors. Replace the A/C Pressure Transducer if no problems were found with the connectors.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to STANDARD PROCEDURE .
  No
  - Go To 4
CHECK THE (C18) A/C PRESSURE SIGNAL CIRCUIT FOR A SHORT TO GROUND
1. Turn the ignition off.
2. Disconnect the PCM C1 harness connector.
3. Measure the resistance between ground and the (C18) A/C Pressure Signal circuit at the A/C Pressure Transducer harness connector.
  Is the resistance above 10k Ohms?
  
  Yes
  - Go To 5
  No
  - Repair the (C18) A/C Pressure Signal circuit for a short to ground.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to STANDARD PROCEDURE .
CHECK FOR THE (C18) A/C PRESSURE SIGNAL CIRCUIT SHORTED TO THE (K914) SENSOR GROUND CIRCUIT
1. Measure the resistance between the (C18) A/C Pressure Signal circuit and the (K914) Sensor Ground circuit at the A/C Pressure Transducer harness connector.
  Is the resistance above 10k Ohms?
  
  Yes
  - Go To 6
  No
  - Repair the short between the (K914) Sensor Ground circuit and the (C18) A/C Pressure Signal circuit.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to STANDARD PROCEDURE .
CHECK FOR EXCESSIVE RESISTANCE IN THE (C18) A/C PRESSURE SIGNAL CIRCUIT
CAUTION:
Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install the GPEC Diagnostic Adaptor to perform the diagnosis.
1. Connect the (special tool #10436, Adapter, GPEC Diagnostic).
2. Measure the resistance of the (C18) A/C Pressure Signal circuit between the A/C Pressure Transducer harness connector and the GPEC Adaptor.
  Is the resistance below 5.0 Ohms?
  
  Yes
  - Go To 9
  No
  - Repair the (C18) A/C Pressure Signal circuit for an open or high resistance.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to STANDARD PROCEDURE .
CHECK THE (F855) 5-VOLT SUPPLY CIRCUIT FOR AN OPEN/HIGH RESISTANCE
1. Turn the ignition off.
2. Disconnect the PCM C2 harness connector.
  CAUTION:
  Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install the GPEC Diagnostic Adaptor to perform the diagnosis.
3. Connect the (special tool #10436, Adapter, GPEC Diagnostic).
4. Measure the resistance of the (F855) 5-Volt Supply circuit from the A/C Pressure Transducer harness connector to the GPEC Adaptor.
  Is the resistance below 5.0 Ohms?
  
  Yes
  - Go To 7
  No
  - Repair the (F855) 5-Volt Supply circuit for an open or high resistance.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to STANDARD PROCEDURE .
CHECK THE (F855) 5-VOLT SUPPLY CIRCUIT FOR A SHORT TO GROUND
1. Measure the resistance between ground and the (F855) 5-Volt Supply circuit in the A/C Pressure Transducer harness connector.
  Is the resistance below 10k Ohms?
  
  Yes
  - Repair the (F855) 5-Volt Supply circuit for a short to ground.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to STANDARD PROCEDURE .
  No
  - Go To 9
POWERTRAIN CONTROL MODULE (PCM)
1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the related A/C Pressure Transducer and the Powertrain Control Module (PCM).
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 A/C Pressure Transducer and the Powertrain Control Module connectors.
4. Refer to any Technical Service Bulletins that may apply.
  Were there any problems found?
  
  Yes
  - Repair as necessary.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to STANDARD PROCEDURE .
  No
  - Replace and program the powertrain control module in accordance with the service information.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to STANDARD PROCEDURE .