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 THE ENGINE FOR PROPER OIL LEVEL
1. Turn the ignition off.
2. Check the engine oil level.
  Is the oil at the proper level?
  
  Yes
  - Go To 3
  No
  - If the engine oil is not at the proper level, restore the engine oil to the proper specification. Turn the on and using the scan tool, erase the DTC. Start the engine and allow it to idle. If the DTC does not return, repair is complete.
  - If the DTC returns, Go To 3
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 4
CHECK THE CRANKCASE PRESSURE SENSOR (F856) 5-VOLT SUPPLY CIRCUIT FOR AN OPEN/HIGH RESISTANCE
1. Turn the ignition off.
2. Disconnect the Crankcase Pressure Sensor harness connector.
3. Turn the ignition on.
4. Measure the voltage on the Crankcase Pressure Sensor (F856) 5-Volt Supply circuit at the FTP Sensor harness connector.
  Is the voltage between 4.9 to 5.1 volts?
  
  Yes
  - Go To 5
  No
  - Repair the Crankcase Pressure Sensor (F856) 5-Volt Supply circuit for an open or high resistance.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
CHECK THE CRANKCASE VENTILATION HOSE
1. Visually inspect the crankcase ventilation hose for the following:
  - Poor sensor fitting
  - Disconnected at the connections points
  - Holes or breaks in the hose
  - Pinched hose or restriction in the hose
  Were any issues found with the crankcase ventilation hose?
  
  Yes
  - Perform the appropriate repair.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Replace the Crankcase Pressure Sensor in accordance with the Service Information.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .