Man MBE 900 Engine 2007 Operator's Guide — page 67 of 158

ENGINE BRAKE SYSTEM be activated only when the engine is in overrun. When constant rpm has been attained, the engine brake is automatically turned off. 2. If you ﬁnd you are still using the service brakes, move the switch to a higher position until you do not need to use the service brakes to slow the vehicle down. Anti-Lock Braking Systems 3. If you are carrying a heavier load and road traction is good, move the progressive braking switch to the “High” position. Vehicles equipped with Anti-lock Braking Systems (ABS) have the ability to turn the engine brake retarder OFF if a wheel-slip condition is detected.

The engine brake will automatically turn itself ON once the wheel slip is no longer detected. The DDEC system will deactivate the engine brake system when the engine speed falls below 1000 rpm or when the vehicle slows down to a pre-set speed, depending on MCM programming. This prevents stalling the engine. Engine brakes can also be used with vehicle Cruise Control TURNED ON. 4. Check your progressive braking switch often for proper position, since road conditions can change quickly. Never skip a step when operating the progressive braking switch. Always go from OFF to LOW, and then to a higher position.

Descending a Long, Steep Grade An explanation of “control speed” may be helpful in understanding how to use the engine brake system while descending a grade. Control Speed is the constant speed at which the forces pushing the vehicle forward on a grade are equal to the forces holding it back, without using the vehicle service brakes. In other words, this is the speed the vehicle will maintain without using the service brakes or fueling. Driving on Flat, Dry Pavement Use the following guidelines when driving on ﬂat, dry pavement: 1. If driving on ﬂat, dry, open stretches with a light load and greater slowing power is not required, place the progressive braking switch in the LOW position.