Code P0300 on the 2024 Jeep Grand Cherokee with the available Multi-Displacement System (MDS) can indicate issues with the cylinder deactivation system causing random misfires. MDS deactivates cylinders during light-load cruising to improve fuel economy, and issues with this system can trigger misfire codes.
Multi-Displacement System Overview
The MDS system uses special lifters that can collapse on command, preventing valve actuation in selected cylinders. When cruising lightly, four cylinders deactivate, reducing pumping losses and fuel consumption. The transition between 4-cylinder and 8-cylinder modes must be seamless.
P0300 and MDS Relationship
If MDS lifters don't fully collapse or don't lock back in properly, affected cylinders may misfire during transitions or while in 4-cylinder mode. This can register as random misfires (P0300) because the misfires occur across different cylinders as the system activates and deactivates.
Common MDS Issues
Low oil pressure affecting lifter operation, stuck MDS solenoids, worn MDS lifters, or contaminated oil affecting lifter response can cause issues. Engine oil must be the correct viscosity and changed regularly for proper MDS operation.
Diagnostic Approach
Check for specific cylinder misfire codes that might point to MDS cylinders. Monitor MDS status during test drive. Verify oil pressure and oil change history. Check for MDS-specific codes in addition to P0300. Some drivers choose to have MDS disabled if problems persist.