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.

READ AND RECORD DTCS AND ENVIRONMENTAL DATA - ERASE DTCS AND CHECK FOR THE DTC TO RETURN
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 2
  No
  - Perform the INTERMITTENT CONDITION diagnostic procedure. Refer to INTERMITTENT CONDITION .
CHECK FOR OTHER DTCS
1. Refer to the recorded DTCs.
  Are there any 5-Volt Supply DTCs present?
  
  Yes
  - Perform the applicable diagnostic procedure(s). Refer to DIAGNOSTIC CODE INDEX .
  No
  - Go To 3
CHECK THE CRANKCASE PRESSURE SENSOR (K926) SIGNAL CIRCUIT FOR A SHORT TO GROUND
1. Turn the ignition off.
2. Disconnect the Crankcase Pressure Sensor harness connector.
3. Disconnect the PCM C2 harness connector.
4. Check for continuity between ground and the Crankcase Pressure Sensor (K926) Signal circuit at the Crankcase Pressure Sensor harness connector.
  Is there continuity between ground and the Crankcase Pressure Sensor (K926) Signal circuit?
  
  Yes
  - Repair the Crankcase Pressure Sensor (K926) Signal circuit for a short to ground.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Go To 4
CHECK FOR THE CRANKCASE PRESSURE SENSOR (K926) SIGNAL CIRCUIT SHORTED TO THE (K914) SENSOR RETURN CIRCUIT
1. Check for continuity between the Crankcase Pressure Sensor (K926) Signal circuit and the (K914) Sensor return circuit at the Crankcase Pressure Sensor harness connector.
  Is there continuity between the Crankcase Pressure Sensor (K926) Signal circuit and the (K914) Sensor return circuit?
  
  Yes
  - Repair the short between the Crankcase Pressure Sensor (K926) Signal circuit and the (K914) Sensor return circuit.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Go To 5
CRANKCASE PRESSURE SENSOR
1. Reconnect the PCM C2 harness connector.
2. Connect a jumper between the Crankcase Pressure Sensor (K926) Signal circuit and the (F856) 5-Volt Supply circuit.
3. Turn the ignition on.
  NOTE:
  The scan tool should display the P051D-CRANKCASE PRESSURE SENSOR CIRCUIT HIGH DTC as active or pending with the jumper in place.
4. With the scan tool, read DTCs and record on the repair order.
  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 6
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
  - Repair as necessary.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Replace the Powertrain Control Module in accordance with the Service Information.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .