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 system voltage or sensor reference DTCs before continuing with this test.
1. Turn the ignition on.
2. With the scan tool, view DTCs.
  Is the DTC active?
  
  Yes
  - Go To 2
  No
  - Perform the INTERMITTENT CONDITION diagnostic procedure. Refer to STANDARD PROCEDURE .
CHECK THE (N8) 5-VOLT SUPPLY CIRCUIT VOLTAGE
1. Disconnect the CNG Tank Pressure Sensor harness connector.
2. Measure the voltage of the (N8) 5-Volt Supply circuit at the CNG Tank Pressure Sensor harness connector.
  Is the voltage between 4.8 and 5.2 volts
  
  Yes
  - Go To 3
  No
  - Repair the (N8) 5-Volt Supply circuit for an open.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to STANDARD PROCEDURE .
CHECK THE (N70) CNG TANK PRESSURE SENSOR SIGNAL CIRCUIT FOR AN OPEN/HIGH RESISTANCE
1. Turn the ignition off.
2. Disconnect the PCM C1 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 (N70) CNG Tank Pressure Sensor Signal circuit between the CNG Tank Pressure Sensor harness connector and the GPEC Adaptor.
  Is the resistance above below 5.0 Ohms?
  
  Yes
  - Go To 4
  No
  - Repair the (N70) CNG Tank Pressure Sensor Signal circuit for an open or high resistance.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to STANDARD PROCEDURE .
CHECK FOR THE (N10) SENSOR RETURN CIRCUIT AN OPEN/HIGH RESISTANCE
1. Measure the resistance of the (N10) Sensor Return circuit between the CNG Tank Pressure Sensor harness connector and the GPEC Adapter.
  Is the resistance above below 5.0 Ohms?
  
  Yes
  - Go To 5
  No
  - Repair the (N10) Sensor Return circuit for an open or high resistance.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to STANDARD PROCEDURE .
CNG TANK PRESSURE SENSOR
1. Turn the ignition off.
2. Reconnect the PCM C1 harness connector.
3. Connect a jumper between the (N10) Sensor Return circuit and the (N70) CNG Tank Pressure Sensor Signal circuit at the CNG Tank Pressure Sensor harness connector.
  NOTE:
  Take care not to damage or spread the terminals.
4. Turn the ignition on.
5. With the scan tool, view DTCs.
  NOTE:
  The P01A0-ALTERNATIVE FUEL TANK PRESSURE SENSOR CIRCUIT LOW DTC should become active or pending with the jumper in place.
  
  Does the DTC set as described above?
  
  Yes
  - Replace the CNG Tank Pressure Sensor in accordance with the service information.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to STANDARD PROCEDURE .
  No
  - Go To 6
POWERTRAIN CONTROL MODULE (PCM)
1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the CNG Tank Pressure Sensor 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.
4. Monitor the scan tool data relative to this circuit and wiggle test the wiring and connectors.
5. Look for the data to change or for the DTC to reset during the wiggle test.
6. Perform any Technical Service Bulletins that may apply.
  Were any problems found?
  
  Yes
  - Repair as necessary.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to STANDARD PROCEDURE .
  No
  - Replace and program the Powertrain Control Module (PCM) in accordance with the service information. Refer to MODULE, POWERTRAIN CONTROL, REMOVAL .
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to STANDARD PROCEDURE .