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
LH-SFI Equipped Vehicles
- A 4-pole CTS is used for EZL/AKR ignition systems. It combines 2 sensors into one housing. Neither sensor is connected to housing for grounding purposes. One sensor is for EZL/AKR ignition system and other sensor is for LH-SFI fuel injection system. Both CTS sensors are internally identical so that harness connector can be attached in any position to CTS.
- Unplug CTS harness connector. Using ohmmeter, check resistance value across diagonally opposite terminals of CTS. See Fig 1 . Refer to appropriate COOLANT TEMPERATURE SENSOR SPECIFICATIONS table for resistance and voltage specification at engine coolant temperature. If resistance or voltage values are not to specification, replace coolant temperature sensor.
COOLANT TEMPERATURE SENSOR SPECIFICATIONS (LH-SFI 4.2L)
| Temperature °F (°C) | (1) Ohms | Volts | ||
|---|---|---|---|---|
| -4 (-20) | 15,700 | 5.12-5.60 | ||
| 14 (-10) | 10,000 | 4.49-5.11 | ||
| 32 (0) | 5900 | 4.12-4.48 | ||
| 50 (10) | 3700 | 3.77-4.12 | ||
| 68 (20) | 2500 | 3.36-3.76 | ||
| 86 (30) | 1700 | 2.92-3.35 | ||
| 104 (40) | 1170 | 2.51-2.91 | ||
| 122 (50) | 830 | 2.09-2.50 | ||
| 140 (60) | 600 | 1.69-2.08 | ||
| 158 (70) | 435 | 1.36-1.68 | ||
| 176 (80) | 325 | 1.09-1.35 | ||
| 194 (90) | 245 | .88-1.08 | ||
| 212 (100) | 185 | .75-.87 | ||
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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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