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.
1991 Mercedes Benz 300CEFACTORY OEM SERVICE PROCEDURE
Full-Load Enrichment
- Disconnect throttle valve switch connector. Check resistance of throttle valve switch. In idle speed position, resistance should be infinity. In full load position (wide open throttle), resistance should be zero ohms. If readings are not correct, adjust or replace throttle valve switch. If readings are correct, go to next step.
- For further testing procedures, see Test Step No. 4 (6-cyl.) and see Test Step No. 3 (V8) in the TESTS W/CODES article in this section.
Factory Service Tools
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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.