FixVault

Possible Causes

Possible Causes 
(K451) MDS SOLENOID NO. 1 CONTROL SHORT TO GROUND
(K451) MDS SOLENOID NO. 1 CONTROL OPEN
(Z904) GROUND CIRCUIT OPEN
INSUFFICIENT OIL PRESSURE ACTING ON THE LIFTER LOCKING PINS
OIL PASSAGES RESTRICTED
LIFTER
MDS SOLENOID
POWERTRAIN CONTROL MODULE (PCM)

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. See  DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure  .