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Home >> Jeep >> 2021 >> Grand Cherokee L Laredo, RWD >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 20 (5.7L - DTCS P2167 To U0151) >> DTC Troubleshooting >> P3449-Cylinder 7 Deactivation Control Circuit >> Diagnostic Test

Diagnostic Test

WARNING: This page is about a different variant/trim than selected.
  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  2

    No 

  2. CHECK FOR OTHER DTCS 
    1. Refer to the recorded DTCs.

      Are there any Engine Misfire DTCs active or pending?

      Yes 

      No 

      • Go To  3
  3. 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. Turn the ignition off.
    2. Disconnect the in-line harness connector.
    3. Using a 12-volt test light, jumper from the Ground circuit and the MDS Solenoid 7 (K454) Control circuit in the in-line harness connector (PCM side).
    4. Turn the ignition on.
    5. Using the scan tool, actuate the MDS Solenoid 7.

      Does the 12-volt test light flash on and off?

      Yes 

      • Go To  4

      No 

      • Go To  5
  4. CHECK THE MDS SOLENOID RESISTANCE 
    1. Turn the ignition off.
    2. Measure the resistance between the Ground circuit and the MDS Solenoid 7 (K454) Control circuit in the in-line harness connector (MDS side).

      Is the resistance less than 25 Ohms?

      Yes 

      • Go To  13

      No 

      • Go To  9
  5. CHECK THE GROUND CIRCUIT ON THE PCM SIDE OF THE IN-LINE HARNESS CONNECTOR FOR AN OPEN/HIGH RESISTANCE 
    1. Turn the ignition off.
    2. Using a 12-volt test light connected to the 12-volts, probe the Ground circuit in the in-line harness connector (PCM side).

      Does the test light illuminate brightly?

      Yes 

      • Go To  6

      No 

  6. CHECK THE MDS SOLENOID 7 (K454) CONTROL CIRCUIT ON THE PCM SIDE OF THE IN-LINE HARNESS CONNECTOR SHORTED TO BATTERY VOLTAGE 
    1. Disconnect the PCM C2 harness connector.
    2. Ignition on, engine not running.
    3. Measure the voltage on the MDS Solenoid 7 (K454) Control circuit in the in-line harness connector.

      Does the Voltmeter indicate voltage present?

      Yes 

      • Repair the short to battery voltage in the MDS Solenoid 7 (K454) Control circuit between the PCM harness connector and in-line harness connector.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

      No 

      • Go To  7
  7. CHECK THE MDS SOLENOID 7 (K454) CONTROL CIRCUIT ON THE PCM SIDE OF THE IN-LINE HARNESS CONNECTOR SHORTED TO GROUND 
    1. Turn the ignition off.
    2. Measure the resistance between ground and the MDS Solenoid 7 (K454) Control circuit in the in-line harness connector.

      Is the resistance below 100 Ohms?

      Yes 

      • Repair the short to ground in the MDS Solenoid 7 (K454) Control circuit between the PCM harness connector and the in-line harness connector.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

      No 

      • Go To  8
  8. CHECK THE MDS SOLENOID 7 (K454) CONTROL CIRCUIT ON THE PCM SIDE OF THE IN-LINE HARNESS CONNECTOR FOR AN OPEN/HIGH RESISTANCE 
    1. Measure the resistance of the MDS Solenoid 7 (K454) Control circuit from the in-line harness connector to the PCM harness connector.

      Is the resistance below 5.0 Ohms?

      Yes 

      No 

      • Repair the open in the MDS Solenoid 7 (K454) Control circuit between the in-line harness connector and the PCM C2 harness connector.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  9. CHECK THE GROUND CIRCUIT ON THE MDS SIDE OF THE IN-LINE HARNESS CONNECTOR FOR AN OPEN/HIGH RESISTANCE 
    1. Turn the ignition off.
    2. Gain access to the MDS Solenoid. Refer to SOLENOID, MULTIPLE DISPLACEMENT, REMOVAL AND INSTALLATION, 5.7L .
    3. Disconnect the MDS harness connector.
    4. Measure the resistance of the Ground circuit between the in-line harness connector and the MDS harness connector.

      Is the resistance below 5.0 Ohms?

      Yes 

      • Go To  10

      No 

  10. CHECK THE MDS SOLENOID 7 (K454) CONTROL CIRCUIT ON THE MDS SIDE OF THE IN-LINE HARNESS CONNECTOR FOR A SHORT TO BATTERY VOLTAGE 
    1. Ignition on, engine not running.
    2. Measure the voltage on the MDS Solenoid 7 (K454) Control circuit in the MDS Solenoid 7 harness connector.

      Does the Voltmeter indicate voltage present?

      Yes 

      • Repair the short to battery voltage in the MDS Solenoid 7 (K454) Control circuit between the in-line harness connector and the MDS harness connector.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

      No 

      • Go To  11
  11. CHECK THE MDS SOLENOID 7 (K454) CONTROL CIRCUIT ON THE MDS SIDE OF THE IN-LINE HARNESS CONNECTOR FOR A SHORT TO GROUND 
    1. Turn the ignition off.
    2. Measure the resistance between ground and the MDS Solenoid 7 (K454) Control circuit in the MDS Solenoid 7 harness connector.

      Is the resistance below 100 Ohms?

      Yes 

      • Repair the short to ground in the MDS Solenoid 7 (K454) Control circuit between the in-line harness connector and the MDS harness connector.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

      No 

      • Go To  12
  12. CHECK THE MDS SOLENOID 7 (K454) CONTROL CIRCUIT ON THE MDS SIDE OF THE IN-LINE HARNESS CONNECTOR FOR AN OPEN/HIGH RESISTANCE 
    1. Measure the resistance of the MDS Solenoid 7 (K454) Control circuit from the MDS Solenoid 7 harness connector to the in-line harness connector.

      Is the resistance below 5.0 Ohms?

      Yes 

      No 

      • Repair the open in the MDS Solenoid 7 (K454) Control circuit between the in-line harness connector and the MDS harness connector.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  13. CHECK THE IN-LINE HARNESS CONNECTOR AND GROUND CONNECTION FOR DAMAGE OR IMPROPER FIT 
    1. Inspect the in-line harness connector.
    2. Make sure the Ground terminal and Control terminal are fastened securely into the connector and there are no signs of corrosion or damage.
    3. Check wiring to terminal connection. Look for an internal broken wire under the insulation.
    4. Inspect the Ground for a tight, clean connection.

      Were any problems found?

      Yes 

      No