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 lambda control, function engine 113 - GF07.61-P-4022SM
ENGINE 113.986
ENGINE 113.987
ENGINE 113.988
ENGINE 113.989
The mixture composition is controlled within the narrowest possible limits around λ = 1 in order to achieve a high conversion of the exhaust gases (exhaust gas conversion) in the catalytic converter.
The O2 sensors (G3/3, G3/4) react to the oxygen share in the exhaust and transmit a corresponding voltage signal to the ME control unit (N3/10). This alters the mixture composition by controlling the injection quantity so that λ=1 is obtained. This process is repeated constantly (control loop).
The lambda closed-loop control is operational in the following operating conditions (closed-loop control):
- Coolant temperature < 52°C
- O2 sensors have reached operating temperature
- Engine in idle/partial load range
- Deceleration fuel shutoff not active.
The ME control unit alters the mixture composition with a time delay in order to prevent any risk of jerking.
Example:
Assuming a leaner fuel-air mixture is produced. This has the following consequence, that the O2 sensor voltage drops and the ME control unit compensates for this lean drift through a matching enrichment.
This makes it possible to achieve a fuel-air mixture of approximately λ = 1.
The reading of the lambda control factor with the STAR DIAGNOSIS moves towards +25 % The more the lambda control factor moves in the direction +25 %, the leaner is the fuel-air mixture and the greater is the enrichment of the mixture on the part of the ME control unit.
| Fuel injection valves, component description | Y62 | GF07.03-P-6010SM |
| Crankshaft position sensor component description | L5 | GF07.04-P-6010SM |
| Coolant temperature sensor component description | B11/4 | GF07.04-P-6040SM |
| O2 sensor component description | G3/3, G3/4, G3/5, G3/6 | GF07.04-P-6100SM |
| Hot film MAF sensor component description | B2/5 | GF07.07-P-6000SM |
| ME-SFI [ME] control unit component description | N3/10 | GF07.61-P-6000SM |
| Accelerator pedal sensor, component description | B37 | GF30.20-P-2010SM |
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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.