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 .
CHECKING FOR OTHER PCM DTCS
1. Refer to the recorded DTCs.
  Are there any other DTCs present?
  
  Yes
  - Repair the other DTCs before continuing.
  - Perform the PCM VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Go To 3
CURRENT DTC
1. Turn the ignition on.
2. With the scan tool, erase the PCM DTCs.
3. Test drive the vehicle under various load and speed conditions to attempt to duplicate the fault.
4. With the scan tool, read the PCM DTCs.
  Did the DTC return?
  
  Yes
  - Go To 4
  No
  - Perform the INTERMITTENT CONDITION diagnostic procedure. Refer to INTERMITTENT CONDITION .
FUEL SYSTEM LEAK
1. Turn the ignition off.
2. Inspect the entire fuel system for leakage.
  Is there any evidence of leakage?
  
  Yes
  - Repair as necessary in accordance with the service information.
  - Perform the PCM VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Go To 5
FUEL SYSTEM CONTAMINATION
1. Inspect the fuel system for contamination.
  Is the fuel contaminated?
  
  Yes
  - Repair as necessary in accordance with the Service Information.
  - Perform the PCM VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Go To 6
ATTEMPT TO START ENGINE
1. With the scan tool, erase the PCM DTCs.
2. Attempt to start the engine.
  Does the engine start and idle?
  
  Yes
  - Go To 7
  No
  - Go To 11
FUEL PRESSURE REGULATOR
1. With the scan tool, compare the Fuel Pressure Setpoint with the Actual Fuel Pressure.
  NOTE:
  A sticking Fuel Pressure Regulator is indicated by the Actual Fuel Pressure gradually dropping below the Fuel Pressure Setpoint then suddenly increasing (spiking) above the Fuel Pressure Setpoint.
  
  Does the Actual Fuel Pressure gradually decrease then suddenly increase (spike) above the Fuel Pressure Setpoint?
  
  Yes
  - Replace the Fuel Pressure Regulator in accordance with the Service Information.
  - Perform the PCM VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Go To 8
CHECKING FUEL DELIVERY SYSTEM
1. Perform the CHECKING THE FUEL DELIVERY SYSTEM diagnostic procedure. Refer to CHECKING THE FUEL DELIVERY SYSTEM (HARD START) .
  Were there any problems with the Fuel Delivery System?
  
  Yes
  - Repair as necessary in accordance with the Service Information.
  - Perform the PCM VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Go To 9
FUEL INJECTOR(S)
NOTE:
An injector that sticks open can cause this DTC. A sticking injector will cause the engine to misfire and emit excessive black smoke from the exhaust system.

Does the engine exhibit the symptoms described in the above note?

Yes
- Using the service information, remove and inspect the Fuel Injectors for signs of damage or debris that may cause the injector to stick. Sticking injectors may cause the combustion chamber to become black and oil soaked. Replace Injector(s) as necessary.
- Perform the PCM VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
No
- Go To 10
FUEL PRESSURE REGULATOR
1. Turn the ignition off.
2. Replace the Fuel Pressure Regulator in accordance with the Service Information.
3. Turn the ignition on.
4. With the scan tool, erase the PCM DTCs.
5. Attempt to start and test drive the vehicle.
6. With the scan tool, read the PCM DTCs.
  Did the DTC return?
  
  Yes
  - Replace the High Pressure Pump in accordance with the Service Information. Refer to HIGH PRESSURE FUEL PUMP .
  - Perform the PCM VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Test Complete.
  - Perform the PCM VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
CHECKING FUEL DELIVERY SYSTEM
1. Perform the CHECKING THE FUEL DELIVERY SYSTEM diagnostic procedure. Refer to CHECKING THE FUEL DELIVERY SYSTEM (HARD START) .
  Were there any problems with the Fuel Delivery System?
  
  Yes
  - Repair as necessary in accordance with the service information.
  - Perform the PCM VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Go To 12
FUEL PRESSURE REGULATOR
1. Turn the ignition off.
2. Replace the Fuel Pressure Regulator in accordance with the Service Information.
3. Turn the ignition on.
4. With the scan tool, erase the PCM DTCs.
5. Attempt to start and test drive the vehicle.
6. With the scan tool, read the PCM DTCs.
  Did the DTC return?
  
  Yes
  - Replace the High Pressure Delivery Pump in accordance with the Service Information. Refer to HIGH PRESSURE FUEL PUMP .
  - Perform the PCM VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Test Complete.
  - Perform the PCM VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .