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.
ME-SFI two-sensor control, function - GF07.61-P-3020AMG
ENGINE 156.980 in MODEL 164, 251 up to Model Year 8
ENGINE 156.982 in MODEL 209
ENGINE 156.983 in MODEL 211, 219
ENGINE 156.984 in MODEL 216, 221 up to Model Year 8
The ME engine control unit determines the lambda mean value from the signals of the O 2 sensors downstream of TWC. This value is compared with a stored value for optimum exhaust emissions.
If the deviation is too large after a number of measurements, a correction variable (delay time) is determined for the lambda control.
The correction variable (value for new O 2 sensor upstream TWC approx. 0) makes it possible to compensate for aging of the O 2 sensor upstream of TWC within certain limits. If the correction variable exceeds the limit value, the O 2 sensor upstream of TWC must be replaced.
The correction values are map-controlled and are implemented by the ME-SFI [ME] control unit by adapting the fuel injection.
Two sensor control is only enabled when the catalytic convertors have reached their operating temperature and the O 2 sensors downstream TWC operate correctly.
If limit values are exceeded, or if the plausibility check of the O 2 sensor signal is negative, a fault is stored in the fault memory and the engine diagnosis indicator lamp or for CHECK ENGINE indicator lamp lights up. The stored faults can be read out and erased with the STAR DIAGNOSIS.
The effect of the firewall catalytic converters is monitored based on the O 2
sensor signals downstream of TWC.
| Component description for fuel injection valves | Y62y1-Y62y8 | GF07.03-P-6010AMG | |
| Component description for O 2 sensors | G3/3, G3/4 | O2 sensors upstream of the TWC | GF07.04-P-6100AMG |
| G3/5, G3/6 | O2 sensors downstream of the TWC | GF07.04-P-6100AMH | |
| Component description for the ME-SFI [ME] control unit | N3/10 | GF07.61-P-6000AMG | |
| Component description for the three-way catalytic converter | 157, 158 | GF49.10-P-2010AMG | |
| Component description for engine diagnosis indicator lamp | A1e58 | for model 164, 209, 211, 216, 219, 221, 251 and model 216, 221 with code 494 USA version | GF54.30-P-5010AMG |
| Component description for the "CHECK ENGINE" indicator lamp | A1e26 | except model 216, 221 for code 494 USA version | GF54.30-P-5011AMG |
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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.