P3400-MDS RATIONALITY BANK 1





For a complete wiring diagram Refer to Section 8W.

Theory of Operation


When all criteria has been met, power is supplied to each MDS Solenoid when the engine is making a transition from 8 cylinder mode to 4 cylinder mode. By actuating the solenoid, oil pressure is raised to the pair of lifters that coincide with each particular solenoid. The oil pressure pushes in the locking pins that allows the lifter to collapse, decoupling the valves and camshaft.


  • When Monitored:

    Transition from 8 to 4 cylinder mode.

  • Set Condition:

    O2 sensor readings on Bank 1 side indicate a lean condition while in 4 cylinder mode. One trip fault.


Possible Causes
  
INSUFFICIENT OIL PRESSURE ACTING ON THE LIFTER LOCKING PINS
  
OIL PASSAGES RESTRICTED
  
LIFTER
  
MDS SOLENOID
  

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).



Diagnostic Test

1.ACTIVE DTC



NOTE: Diagnose any Oil Pressure DTCs before continuing.



Is the DTC Active at this time?

Yes
  • Go To 2


No

2.MDS SOLENOID 1






Can you feel and hear the Solenoid Actuating?

Yes
  • Go To 3


No
  • Remove the Solenoid and check for any debris that may be blocking the oil passages to the Solenoid. If the passages are clogged, clean the passages and replace the MDS Solenoid 1. If the passages are not clogged with debris, replace the MDS Solenoid 1.
  • Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

3.MDS SOLENOID 7



Can you feel and hear the Solenoid Actuating?

Yes
  • Go To 4


No
  • Remove the Solenoid and check for any debris that may be blocking the oil passages to the Solenoid. If the passages are restricted, clean the passages and replace the MDS Solenoid 7. If the passages are not clogged with debris, replace the MDS Solenoid 7.
  • Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

4.OIL PASSAGES RESTRICTED







Are the passages blocked?

Yes


No