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 COOLING SYSTEM
1. Turn the ignition off.
2. Check the Low Temperature Cooling System for:
  - Coolant leaks
  - Low Coolant level
  - Improperly bled or air in the system. Perform the FILL AND BLEED COOLING SYSTEM Standard Procedure. Refer to STANDARD PROCEDURE - FILLING .
  - Improper coolant concentration
  Were there any problems found?
  
  Yes
  - Repair the Low Temperature Cooling System as necessary in accordance with the Service Information.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Go To 3
CHECK THE (A501) FUSED B+ CIRCUIT FOR AN OPEN/HIGH RESISTANCE
NOTE:
Verify the integrity of the (A501) Fused B+ supply Fuse.
1. Turn the ignition off.
2. Disconnect the LT Coolant Pump harness connector.
3. Disconnect the Power Distribution Center (PDC) C2 harness connector.
4. Measure the resistance of the (A501) Fused B+ circuit between the LT Coolant Pump harness connector and the Power Distribution Center (PDC) C3 harness connector.
  Is the resistance below 3.0 Ohms?
  
  Yes
  - Go To 4
  No
  - Repair the LT Coolant Pump (A501) Fused B+ circuit for an open or high resistance.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
CHECK THE (Z921) GROUND CIRCUIT FOR AN OPEN/HIGH RESISTANCE
1. Measure the resistance between ground and the (Z921) Ground circuit at the LT Coolant Pump harness connector.
  Is the resistance below 3.0 Ohms?
  
  Yes
  - Go To 5
  No
  - Repair the (Z921) Ground circuit for an open or high resistance.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
INSPECT THE LT COOLANT PUMP WIRING AND CONNECTORS
1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the LT Coolant Pump and the Powertrain Control Module (PCM).
  NOTE:
  When inspecting wiring and connectors be sure to include inspection of midline connectors in the circuit.
2. Look for any chafed, pierced, pinched, or partially broken wires.
3. Look for any loose, or partially broken ground wires.
4. Check for broken, bent, pushed out or corroded terminals. Verify that there is good pin to terminal contact in the LT Coolant Pump and Powertrain Control Module connectors.
  Were there any problems found?
  
  Yes
  - Repair as necessary.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Replace the LT Coolant Pump in accordance with the Service Information.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .