The multi-displacement system in the Dodge Ram deactivates a cylinder bank on the Hemi V-8 engine to improve fuel economy. An unfortunate side effect of this technology is slightly delayed throttle response, and a poor exhaust note in four-cylinder mode when used with an aftermarket exhaust. The system is triggered by a solenoid on a camshaft, and there is no MDS defeat switch in the cabin. The only options for disabling MDS on a Dodge Ram involve software tuning or hardware modifications.
Place the shifter in the "5" position rather than in "Drive." In the "5" position, the transmission will continue to operate as normal -- shifting up and down through the five forward gears -- but MDS will be disabled. This is the only way to disable MDS without performing modifications. While the Ram does have a tow mode (activated by the tow mode button), it only revises transmission shift points, and does not disable MDS.
Disable MDS via the custom options menu on your handheld tuner if you are running a custom tune on your Dodge Ram. Aftermarket performance tunes are installed into your Dodge Ram via a hand-held tuner that is plugged into your truck's OBD port. These tuners have a variety of functions, including the ability to disable the MDS function.
Install the MOPAR hi-performance camshaft for your engine. The MOPAR Hemi high-performance camshaft deactivates the MDS system. The camshaft must be used in conjunction with revised tuning provided by a Mopar ECU, and cannot be used with your stock programming.
