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Home >> Chrysler >> 2011 >> 300 C, RWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 1658 (5.7L CNG - DTCS P0507 To P1456 - 2500 Hd) >> DTC Troubleshooting >> P1456-Fuel Tank Pressure Sensor Circuit Low >> Diagnostic Test

Diagnostic Test

WARNING: This page is about a different car, the 2017 RAM 2500 HD. However, it is still accessible from the selected car via links, so may be relevant.
  1. CHECK FOR AN ACTIVE DTC 
    1. Turn the ignition on.
    2. With the scan tool, read DTCs and record on the repair order.

      Does the scan tool display this DTC as active?

      Yes 

      • Go To  2

      No 

  2. CHECK FOR OTHER DTCS 
    1. Refer to the recorded DTCs.

      Are there any system voltage or 5-volt Sensor reference DTCs active or pending?

      Yes 

      No 

      • Go To  3
  3. CHECK THE (N8) 5-VOLT SUPPLY CIRCUIT VOLTAGE VALUE 
    1. Turn the ignition off.
    2. Disconnect the FTP Sensor harness connector.
    3. Turn the ignition on.
    4. Measure the voltage on the (N8) 5-Volt Supply circuit at the FTP Sensor harness connector.

      Is the voltage between 4.8 and 5.2 volts?

      Yes 

      • Go To  4

      No 

      • Repair the (N8) 5-Volt Supply circuit for an open circuit or short to ground.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  4. CHECK THE ABILITY OF THE PCM TO READ THE FTP SENSOR SIGNAL 
    1. With the scan tool, read DTCs and record on the repair order.
      NOTE:

      The P1457-FUEL TANK PRESSURE SENSOR CIRCUIT HIGH should be active or pending with the connector disconnected.

      Does the scan tool display as described above?

      Yes 

      • Verify that there is good pin to terminal contact in the FTP Sensor and Powertrain Control Module connectors. Replace the FTP Sensor if no problems were found with the connectors.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

      No 

      • Go To  5
  5. CHECK THE (N7) FTP 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 (N7) FTP Sensor Signal circuit at the FTP Sensor harness connector.

      Is the resistance below 3.0 Ohms?

      Yes 

      • Repair the short to ground in the (N7) FTP Sensor Signal circuit.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

      No 

      • Go To  6
  6. CHECK FOR THE (N7) FTP SENSOR SIGNAL CIRCUIT SHORTED TO THE (N10) FTP SENSOR RETURN CIRCUIT 
    1. Measure the resistance between the (N7) FTP Sensor Signal circuit and the (N10) FTP Sensor Return circuit at the FTP Sensor harness connector.

      Is the resistance below 3.0 Ohms?

      Yes 

      • Repair the short between the (N7) FTP Sensor Signal circuit and the (N10) FTP Sensor Return circuit.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

      No 

      • Go To  7
  7. CHECK RELATED HARNESS CONNECTIONS 
    1. Disconnect all PCM harness connectors.
    2. Disconnect all related in-line harness connections (if equipped).
    3. Disconnect the related component harness connectors.
    4. Inspect harness connectors, component connectors, and all male and female terminals for the following conditions:
      • Proper connector installation.
      • Damaged connector locks.
      • Corrosion.
      • Other signs of water intrusion.
      • Weather seal damage (if equipped).
      • Bent terminals.
      • Overheating due to a poor connection (terminal may be discolored due to excessive current draw).
      • Terminals that have been pushed back into the connector cavity.
      • Check for spread terminals and verify proper terminal tension.

      Repair any conditions that are found.

    5. Connect all PCM harness connectors. Be certain that all harness connectors are fully seated and the connector locks are fully engaged.
    6. Connect all in-line harness connectors (if equipped). Be certain that all connectors are fully seated and the connector locks are fully engaged.
    7. Connect all related component harness connectors. Be certain that all connectors are fully seated and the connector locks are fully engaged.
    8. With the scan tool, erase DTCs.
    9. Test drive or operate the vehicle in accordance with the when monitored and set conditions.
    10. With the scan tool, read DTCs and record on the repair order.

      Did the DTC return?

      Yes 

      No 

      • The wiring or poor connection problem has been repaired.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
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