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Home >> Jeep >> 2014 >> Wrangler Sahara, Standard Trans >> Repair and Diagnosis >> External Pages >> Different car >> Section 79 (2.4L - DTCS P0443 To P1593) >> Diagnosis And Testing >> P1457-Fuel Tank Pressure Sensor Circuit High >> Diagnostic Test

Diagnostic Test

WARNING: This page is about a different car, the 2014 Dodge Journey. However, it is still accessible from the selected car via links, so may be relevant.
  1. ACTIVE DTC 
    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  2

      No 

  2. FTP SENSOR 
    Fig 1: Fuel Tank Sensor Harness Connector End View
    GC0106774Courtesy of CHRYSLER GROUP, LLC
    1. Turn the ignition off.
    2. Disconnect the FTP harness connector.
    3. Connect a jumper wire between the (N7) FTP Signal circuit and the (K917) Sensor ground circuit in the Sensor harness connector.
    4. Ignition on, engine not running.
    5. With the scan tool, monitor the FTP voltage.
      NOTE:

      The sensor voltage should be approximately 0.0 Volts (plus or minus 0.1 volt) with the jumper wire in place.

      Does the scan tool display the voltage as described above?

      Yes 

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

      No 

      • Go To  3
        NOTE:

        Remove the jumper wire before continuing.

  3. (N7) FTP SIGNAL CIRCUIT SHORTED TO VOLTAGE 
    Fig 2: Checking FTP Signal Circuit For A Short To Voltage
    GC0106775Courtesy of CHRYSLER GROUP, LLC
    1. Turn the ignition off.
    2. Disconnect the C1 and C4 PCM harness connectors.
    3. Ignition on, engine not running.
    4. Measure the voltage on the (N7) FTP Signal circuit in the FTP harness connector.

      Is there any voltage present?

      Yes 

      • Repair the short to battery voltage in the (N7) FTP Signal circuit.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to PCM VERIFICATION TEST .

      No 

      • Go To  4
  4. (N7) FTP SIGNAL CIRCUIT OPEN 
    Fig 3: Checking FTP Signal Circuit For An Open
    GC0106771Courtesy of CHRYSLER GROUP, LLC
    1. Turn the ignition off.
      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 PCM Pinout Box to perform diagnosis.

    2. Measure the resistance of the (N7) FTP Signal circuit from the FTP harness connector to the appropriate terminal of the PCM Pinout Box 8815.

      Is the resistance below 5.0 Ohms?

      Yes 

      • Go To  5

      No 

      • Repair the open in the (N7) FTP Signal circuit.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to PCM VERIFICATION TEST .
  5. (N7) FTP SIGNAL CIRCUIT SHORTED TO THE (F856) 5-VOLT SUPPLY CIRCUIT 
    Fig 4: Checking FTP Signal Circuit For A Short To The 5-Volt Supply Circuit
    GC0106776Courtesy of CHRYSLER GROUP, LLC
    1. Measure the resistance between the (N7) FTP Signal circuit and the (F856) 5-volt Supply circuit in the FTP harness connector.

      Is the resistance below 100 Ohms?

      Yes 

      • Repair the short between the (F856) 5-volt Supply circuit and the (N7) FTP Signal circuit.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to PCM VERIFICATION TEST .

      No 

      • Go To  6
  6. (K917) SENSOR GROUND CIRCUIT OPEN 
    Fig 5: Checking FTP Sensor Ground Circuit For An Open
    GC0106777Courtesy of CHRYSLER GROUP, LLC
    1. Measure the resistance of the (K917) Sensor ground circuit from the FTP harness connector to the appropriate terminal the PCM Pinout Box 8815.

      Is the resistance below 5.0 Ohms?

      Yes 

      • Go To  7

      No 

      • Repair the open in the (K917) Sensor ground circuit.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to PCM VERIFICATION TEST .
  7. POWERTRAIN CONTROL MODULE (PCM) 
    1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the FTP 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 FTP and Powertrain Control Module connectors.
    4. Perform any Technical Service Bulletins that may apply.

      Were there any problems found?

      Yes 

      No