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.
1987 Mercedes Benz 300DFACTORY OEM SERVICE PROCEDURE
Reference Resistor
- With engine off, disconnect reference resistor connector. Reference resistor is located next to altitude correction capsule. Connect multimeter and set to volt scale.
- Probe and check voltage between terminals No. 1 and 2. Voltage reading should be 5 volts. If voltage reading is to specification, replace reference resistor. If voltage reading is not to specification, repair open circuit.
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.