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Home >> Jeep >> 2024 >> Grand Cherokee Summit >> Repair and Diagnosis >> External Pages >> Different car >> Section 36 (5.7L - DTCS P2504 To P3400) >> DTC Troubleshooting >> P3400-Cylinder Deactivation System - Bank 1 >> Diagnostic Test

Diagnostic Test

WARNING: This page is about a different car, the 2024 Jeep Grand Cherokee L. 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 
    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 Next Step

      No 

  2. CHECK FOR OTHER DTCS 
    NOTE:

    Diagnose any Misfire DTCs before continuing.

    1. Refer to the recorded DTCs.

      Are there any Deactivation or Oil Pressure DTCs active or pending?

      Yes 

      No 

      • Go To Next Step
  3. CHECK THE MDS SOLENOID 1 AND 7 CONNECTORS 
    1. Turn the ignition off.
    2. Inspect the MDS Solenoid harness connectors, jumper connectors, and all male and female terminals for the following conditions:
      • Proper connector installation.
      • Damaged connector locks.
      • Corrosion.
      • Other signs of water intrusion.
      • Weather seal damage (if equipped).
      • Bent terminals.
      • Overheating due to a poor connection (terminal may be discolored due to excessive current draw).
      • Terminals that have been pushed back into the connector cavity.
      • Check for spread terminals and verify proper terminal tension.

      Were and problems found?

      Yes 

      No 

      • Go To Next Step
  4. CHECK THE MDS SOLENOID 1 OPERATION USING THE SCAN TOOL ACTUATOR 
    NOTE:

    The DTC must not be active for the actuator test to operate properly, clear all DTC before continuing.

    1. Turn the ignition off.
    2. Remove the Intake Manifold in accordance with the Service Information. Refer to MANIFOLD, INTAKE, REMOVAL AND INSTALLATION, 5.7L .
    3. Turn the ignition on.
    4. With the scan tool actuate the MDS Solenoid 1.

      Can you feel and hear the Solenoid Actuating?

      Yes 

      • Go To Next Step

      No 

  5. CHECK THE MDS SOLENOID 7 OPERATION USING THE SCAN TOOL ACTUATOR 
    NOTE:

    The DTC must not be active for the actuator test to operate properly, clear all DTC before continuing.

    1. With the scan tool actuate the MDS Solenoid 7.

      Can you feel and hear the Solenoid Actuating?

      Yes 

      • Go To Next Step

      No 

  6. CHECK FOR RESTRICTED OIL PASSAGES 
    1. Turn the ignition off.
    2. Remove both Solenoids on Bank 1 of the engine block. Refer to SOLENOID, MULTIPLE DISPLACEMENT, REMOVAL AND INSTALLATION, 5.7L .
    3. Remove the Bank 1 Cylinder Head in accordance with the Service Information. Refer to CYLINDER HEAD ASSEMBLY, REMOVAL AND INSTALLATION, 5.7L .
    4. Remove the Lifters from the left engine bank.
    5. Inspect the oil passages to the Solenoids and from the Solenoids to the lifters.

      Are the passages blocked?

      Yes 

      • Clean the oil passages as necessary. If the entire engine is restricted disassembly of the entire engine block may be necessary.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

      No 

      • Replace both sets of lifters if no other possible causes remain.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .