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.

CNG RAIL TEMPERATURE
1. Turn the ignition on.
2. If possible, allow the vehicle to sit with the ignition off for 480 minutes in an environment where the temperature is consistent and above -7°C (19.4°F).
3. With the scan tool, compare the CNG Rail Temperature Sensor reading to the ECT, AAT and IAT sensors readings.
  Is the temperature difference greater than 15°C (59°F) between the CNG Rail Temperature Sensor and either of the ECT, IAT or AAT Sensor?
  
  Yes
  - Go To 2
  No
  - Perform the INTERMITTENT CONDITION diagnostic procedure. Refer to STANDARD PROCEDURE .
ACTIVE DTC
1. If possible, allow the vehicle to sit with the ignition off for 480 minutes in an environment where the temperature is consistent and above -7°C (19.4°F).
2. Test drive the vehicle. The vehicle speed must exceed 48 kmh (30 mph) during the test drive. Do not cycle the ignition off when the test drive is completed.
3. With the scan tool, select view DTCs.
  Is the status active or pending for this DTC?
  
  Yes
  - Go To 3
  No
  - Perform the INTERMITTENT CONDITION diagnostic procedure. Refer to STANDARD PROCEDURE .
CHECK FOR EXCESSIVE RESISTANCE IN THE (K163) CNG RAIL TEMPERATURE SENSOR SIGNAL CIRCUIT
1. Turn the ignition off.
2. Disconnect the CNG Rail Sensor harness connector.
3. 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.
4. Connect the (special tool #10436, Adapter, GPEC Diagnostic).
5. Measure the resistance of the (K163) CNG Rail Temperature Sensor Signal circuit between the CNG Rail Sensor harness connector and the GPEC Adaptor.
  Is the resistance below 5.0 Ohms?
  
  Yes
  - Go To 4
  No
  - Repair the (K163) CNG Rail Temperature Sensor Signal circuit for an open or high resistance.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to STANDARD PROCEDURE .
CHECK FOR EXCESSIVE RESISTANCE IN THE (K900) SENSOR RETURN CIRCUIT
1. Measure the resistance of the (K900) Sensor Return circuit between the CNG Rail Sensor harness connector and the GPEC Adaptor.
  Is the resistance below 5.0 Ohms?
  
  Yes
  - Go To 5
  No
  - Repair the (K900) Sensor Return circuit for an open or high resistance.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to STANDARD PROCEDURE .
CNG RAIL SENSOR
1. Turn the ignition off.
2. Reconnect the PCM C2 harness connector.
3. Turn the ignition on.
4. With the scan tool, view DTCs.
  NOTE:
  The PCM should display a P01B7-ALTERNATIVE FUEL RAIL TEMPERATURE SENSOR CIRCUIT HIGH DTC with the connector unplugged.
5. Connect a jumper between the (K900) Sensor Return circuit and the (K162) CNG Rail Pressure Sensor Signal circuit at the CNG Rail Sensor harness connector.
  NOTE:
  The PCM should display a P01B6-ALTERNATIVE FUEL RAIL TEMPERATURE SENSOR CIRCUIT LOW DTC with the jumper in place.
6. With the scan tool, view DTCs.
  Do the DTCs set as described above?
  
  Yes
  - Replace the CNG Rail 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 Rail 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 .