Overheating/pinging protection, function - GF07.61-P-4027G

ENGINE 273 in MODEL 463.202/222/236/237 up to 31.5.12 as of model year 2009/YoM 08

Fig 1: Identifying Overheating/Pinging Protection Function Chart

Courtesy of MERCEDES-BENZ USA

Function requirements for overheating/knock protection, general points

Circuit 87M ON (engine control ON)
Engine running

Overheating/knock protection, general points

In case of thermal overload, the overheating/knock protection protects against engine damage and overheating damage to the firewall catalytic converter.

The ME-SFI [ME] control unit controls the overheating/knock protection according to information from the following sensors:

Hot film MAF sensor, engine load
Intake air temperature sensor
Coolant temperature sensor
Crankshaft Hall sensor, engine speed

Overheating/knock protection function sequence

If the coolant or intake air temperature is too high, the ME-SFI [ME] control unit no longer fully opens the throttle valve actuator, depending on engine speed and load. The ME-SFI [ME] control unit shortens the injection time at the fuel injection valves (Y62) according to the lower air mass.

The ME-SFI [ME] control unit also actuates the heating element in the three-disk thermostat valve, so that the three-disk thermostat is fully open and all the coolant is cooled by the engine radiator.

Component description for ME-SFI [ME] control unit

N3/10

GF07.61-P-6000G