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.
1993 Mercedes Benz 400EFACTORY OEM SERVICE PROCEDURE
Control Units
CONTROL UNITS LOCATION
| Component | Location |
|---|---|
| ABS Control Module - Convertible | Right rear of engine compartment, in module box. See Figure . |
| ABS Control Module - Coupe | Right rear of engine compartment, in module box. See Figure . |
| ABS/ASR Control Module | Right rear of engine compartment, in module box. See Figure . |
| A/C Compressor Control Module | Right rear engine compartment, on fenderwell. See Figure . |
| A/C Control Unit | Upper right side of passenger's footwell. |
| ADS Control Unit | In module box, on right rear of engine compartment. |
| Anti-Theft Alarm Control Module - Convertible | Left side of luggage compartment, behind trim panel. See Figure . |
| Anti-Theft Alarm Control Module - Coupe | Under passenger's side footwell. See Figure . |
| A/T Control Unit (5-Speed) | Right rear of engine compartment, in module box. |
| Automatic A/C Push-Button Control Module | In center console. See Figure . |
| Automatic Locking Differential (ASD) Control Module | Right rear of engine compartment, in module box. See Figure . |
| Base Module | Right rear of engine compartment, in module box. See Figure . |
| Continuous Fuel Injection Control Module | Right rear of engine compartment, in module box. See Figure . |
| Convenience Control Module | Under left rear seat. See Figure . |
| Cruise Control/Engine Overload Protection Relay Module | Right rear of engine compartment, in module box. See Figure . |
| Cruise Control/Idle Speed Control Module | Right rear of engine compartment, in module box. See Figure . |
| Diagnostic Module (California Version Engines 104/119) | Under dash, left of steering column. See Figure . |
| Electronic Accelerator/Cruise Control/Idle Speed Control Module (N4/1) | Right rear of engine compartment, in module box. See Figure . |
| Electronic Accelerator/Cruise Control Module | Right rear of engine compartment, in module box. See Figure . |
| Engine Systems Control Module | Right rear of engine compartment, in module box. See Figure . |
| Exterior Light Failure Monitoring Unit | Left rear of engine compartment, in fuse/relay block. See Figure . |
| Front Seat Heater Control Module | Under left rear seat. See Figure . |
| Fuel Pumps Relay Module | Right rear of engine compartment, in module box. See Figure . |
| HFM-SFI Engine Control Module | Right rear of engine compartment, in module box. See Figure . |
| Ignition Control Module (Knock Sensor) | Left front of engine compartment, on fenderwell. See Figure . |
| Left Control Module (N3/1) | Right rear of engine compartment, in module box. See Figure . |
| Left Head Restraint Adjustment Relay Module | Under left front seat. See Figure . |
| Left Power Seat Control Module (With Or Without Memory) | Under left front seat. See Figure . |
| Left Seat Belt Extender Control Module | Under left side of rear seat. See Figure . |
| LH Sequential Multiport Fuel Injection Control Module | Right rear of engine compartment, in module box. See Figure . |
| Mirror/Steering Column Adjustment Control Unit (W/Memory) | Behind right side of dash. |
| Oxygen Sensor (2) (After TWC) Heater Relay Module | Left rear of engine compartment, in fuse module box. See Figure . |
| Overvoltage Protection Relay Module | Right rear of engine compartment, in module box. See Figure . |
| Power Soft Top Control Module | Left side of luggage compartment, behind trim panel. See Figure . |
| Right Head Restraint Adjustment Relay Module | Under right front seat. See Figure . |
| Right Power Seat Control Module (With Or Without Memory) | Under right front seat. See Figure . |
| Right Seat Belt Extender Control Module | Under right side of rear seat. See Figure . |
| Roll Bar Control Module (Crash Deployment) | Under right front seat. See Figure . |
| Roll Bar Control Module (Manual Soft Top) | Under rear passenger-side seat. See Figure . |
| Seat Belt/Keys/Lights Warning Module & Daytime Running Lamp Control Module | In dash, behind instrument cluster. See Figure . |
| Speed Sensitive Power Steering Control Unit | In module box, right rear of engine compartment. |
| SRS (Air Bag) Control Module | Under center console, forward of shift lever. See Figure . |
| Starter Lock-Out Relay Module (ATA) | In dash, behind instrument cluster. See Figure . |
| Stationary Heater Control Unit | Behind right side of dash. |
| Trailer Recognition Control Unit | Right front of luggage compartment. |
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.
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