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.
1990 Mercedes Benz 350SDFACTORY OEM SERVICE PROCEDURE
Connector Abbreviation Definitions
CONNECTOR ABBREVIATIONS DEFINITIONS - DIESEL
| Connector | Definition |
|---|---|
| B 2/1 | Airflow Sensor |
| B 2/1a | Intake Air Temperature Sensor |
| B 5/1 | Air Pressure Sensor |
| B 11/4 | Coolant Temperature Sensor (EDS) |
| F 1 | Fuse Box |
| G 1 | Battery |
| K 1/1 | Overvoltage Protection Relay |
| L 3 | Speed Sensor |
| L 3x1 | Connector For Speed Sensor |
| L 7 | Fuel Rack Position Sensor |
| N 6 | A/C Compressor Control Unit |
| N 39 | EDS Control Unit |
| S 2/2 | Glow/Starter Switch |
| S 30/1 | Kickdown Switch |
| W 10 | Ground Connection |
| X 11/4 | Diagnostic Connector |
| X 26 | Engine Harness-To-Interior Connector |
| Y 22 | Electromagnetic Actuator (ELR) |
| Y 30 | Engine Overload Protection Switchover Valve |
| Y 31/1 | EGR Vacuum Valve Transducer |
| Y 31/2 | Intake Manifold Air Press. Control Valve Vacuum Transducer |
| Y 31/3 | Wastegate Vacuum Transducer |
| 100 | Intake Manifold Air Press. Control Valve Vacuum Actuator |
Factory Service Tools
Use the Manual With the Right Hardware
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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.