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Home >> Jeep >> 2024 >> Wagoneer Carbide, RWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 35 (3.0L - DTCS P04DB-00 To P051D-00) >> DTC Troubleshooting >> P051D-00-Crankcase Pressure Sensor Circuit High >> Diagnostic Test

Diagnostic Test

WARNING: This page is about a different car, the 2024 Jeep Grand Wagoneer L and 2024 Jeep Grand Wagoneer. However, it is still accessible from the selected car via links, so may be relevant.
  1. READ AND RECORD DTCS AND ENVIRONMENTAL DATA - ERASE DTCS AND CHECK FOR THE DTC TO RETURN 
    NOTE:

    If there are any 5-Volt Supply DTCs present, perform the diagnostics for those DTCs before continuing with this one.

    1. With the scan tool, read DTCs in all Electronic Control Units (ECUs) and record on the repair order.
    2. For future reference, with the scan tool, run and save a vehicle Scan Report and all related recorded data.
    3. With the scan tool, erase all DTCs.
    4. Turn the ignition off for a minimum of 10.0 seconds.
    5. Turn the ignition on.
    6. Using the When Monitored and Set Conditions above and recorded data, operate the vehicle in the conditions that set the DTC.
    7. With the scan tool, read DTCs.

      Did the DTC return?

      Yes 

      • Go To  1

      No 

  2. CHECK THE (F856) 5-VOLT SUPPLY CIRCUIT FOR A SHORT TO VOLTAGE 
    1. Turn the ignition off.
    2. Disconnect the Crankcase Pressure Sensor harness connector.
    3. Turn the ignition on.
    4. Measure the voltage on the (F856) 5-Volt Supply circuit at the Crankcase Pressure Sensor harness connector.

      Is the voltage above 5.2 volts?

      Yes 

      • Repair the (F856) Crankcase Pressure Sensor Signal circuit for a short to voltage.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

      No 

      • Go To  3
  3. CHECK THE (K926) CRANKCASE PRESSURE SENSOR SIGNAL CIRCUIT FOR A SHORT TO VOLTAGE 
    1. Measure the voltage on the (K926) Crankcase Pressure Sensor Signal circuit at the Crankcase Pressure Sensor harness connector.

      Is the voltage above 5.2 volts?

      Yes 

      • Repair the (K926) Crankcase Pressure Sensor Signal circuit for a short to voltage.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

      No 

      • Go To  4
  4. CHECK THE (K926) CRANKCASE PRESSURE SENSOR SIGNAL CIRCUIT FOR A SHORT TO THE (F856) 5-VOLT SUPPLY CIRCUIT 
    1. Turn the ignition off.
    2. Disconnect the PCM C2 harness connector.
    3. Check for continuity between the (K926) Crankcase Pressure Sensor Signal circuit and the (F856) 5-Volt Supply circuit at the Crankcase Pressure Sensor harness connector.

      Is there continuity between the (K926) Crankcase Pressure Sensor Signal circuit and the (F856) 5-Volt Supply circuit?

      Yes 

      • Repair the short between the (K926) Crankcase Pressure Sensor Signal circuit and the (F856) 5-Volt Supply circuit.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

      No 

      • Go To  5
  5. CHECK THE (K914) SENSOR RETURN CIRCUIT FOR AN OPEN/HIGH RESISTANCE 
    1. Measure the resistance of the (K914) Sensor Return circuit between the Crankcase Pressure Sensor harness connector and the PCM connector.

      Is the resistance below 3.0 Ohms?

      Yes 

      • Go To  6

      No 

      • Repair the (K914) Sensor Return circuit for an open/high resistance.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  6. CHECK THE (K926) CRANKCASE PRESSURE SENSOR SIGNAL CIRCUIT FOR AN OPEN/HIGH RESISTANCE 
    1. Measure the resistance of the (K926) Crankcase Pressure Sensor Signal circuit between the Crankcase Pressure Sensor harness connector and the PCM connector.

      Is the resistance below 3.0 Ohms?

      Yes 

      • Go To  7

      No 

      • Repair the (K926) Crankcase Pressure Sensor Signal circuit for an open/high resistance.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  7. CRANKCASE PRESSURE SENSOR 
    1. Reconnect the PCM C2 harness connector.
    2. Connect a jumper between the (K926) Crankcase Pressure Sensor Signal circuit and the (K914) Sensor Return circuit at the Crankcase Pressure Sensor harness connector.
    3. Turn the ignition on.
    4. With the scan tool, read DTCs and record on the repair order.
      NOTE:

      The scan tool should display the P051C-CRANKCASE PRESSURE SENSOR CIRCUIT LOW DTC as active or pending with the jumper in place.

      Does the DTC display as described above?

      Yes 

      • Replace the Crankcase Pressure Sensor in accordance with the Service Information.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

      No 

      • Go To  8
  8. POWERTRAIN CONTROL MODULE 
    1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Crankcase 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 Service Bulletins that may apply.

      Were any problems found?

      Yes 

      No 

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