The ME limiting maximum vehicle speed function - GF07.61-P-3007V

ENGINE 273.961 in MODEL 216, 221 up to Model Year 8 

Shown on Engine 272.963 in Model 171 

Fig 1: Identifying ME Limiting Maximum Vehicle Speed Components

Courtesy of MERCEDES-BENZ USA

The ME control unit detects the engine speed via the crankshaft Hall sensor signal. As a protection for the engine and the drive train, engine speed is limited by retarding the ignition timing and switching off the fuel injection valves if the following conditions exist:

1. 1. Transmission overload protection 
2. 1.1 Torque converter protection of automatic transmission 

   In order to protect the torque converter in selector lever positions P and N (no power flow) from excessive static internal pressure, engine speed is limited to approx. 4200 RPM.

3. 1.2 Mechanical transmission (no gear engaged) 

In order to avoid damage to the transmission engine speed is limited to approx. 4000 RPM.

2nd Limiting maximum engine speed when driving 

In order to protect the engine from the consequences of impermissibly high revs, engine speed is limited to 6000 RPM. The driving mode is detected from the vehicle speed signal.

3rd Throttle valve actuator defective 

If the throttle valve actuator is faulty, the engine speed in neutral is restricted to approx. 1400 RPM and in driving mode to approx. 1800 RPM.