Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Overheating/pinging protection, function - GF07.61-P-4027MAS
ENGINE 156.984 in MODEL 216.377, 221.077 /177 as of Model Year 09 /AEJ 08
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 control unit (N3/10) controls the overheating/knock protection according to information from the following sensors:
- LH and RH hot film MAF sensor (B2/6, B2/7), engine load
- Coolant temperature sensor (B11/4)
- Intake air temperature sensor (B17)
- Crankshaft Hall sensor (B70), motor speed
Overheating/knock protection function sequence
If coolant or intake air temperature is too high, the ME-SFI control unit no longer fully opens the front and rear throttle valve actuators (M16/3, M16/4), depending on engine speed and load. The ME-SFI control unit shortens the injection time at the fuel injection valves (Y62) according to the lower air mass.
The ME-SFI control unit also actuates the two-disk thermostat heating element (R48), so that the two-disk thermostat is fully opened and all the coolant is cooled by the engine radiator.
| Electrical function schematic for overheating/ knocking protection, function ME | Model 216 | PE07.61-P-2777-97CAC | |
| Model 221 | PE07.61-P-2777-97SAC | ||
| ME-SFI [ME] control unit, component description | N3/10 | GF07.61-P-6000MAS |
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.