I have a 1993 300E with 104 engine. This is the same engine as the 94-5 320E.

Can someone tell me where the engine coolant temperature sensor is located. Is it east to get to? If anyone can provide a picture, that would be great.

Does the sensor connect to the engine wiring harness? How many prongs are on that connector?

There are 3 coolant temp sensors ..which one are you concerned with???

__________________
A Dalton

The ECT that I am looking for is the one that causes 2 flashes "ECT sensor" on the code reader while testing Pin 8 ECU.

Side mounted sensor under thermo housing

http://catalog.worldpac.com/mercedesshop/sophio/wizard.jsp?partner=mercedesshop&clientid=catalog.mercedesshop&baseurl=http://catalog.peachparts.com/&cookieid=2AO123CS42DW029DXP&year=1993&make=MB&model=300-E-004&category=C&part=Water+Temp.+Sensor

__________________
A Dalton

Thanks, Arthur.

If this ECT sensor is bad, would it cause cold start problems and bad gas mileage.

Is the Pin to test emissions on Pin 6?

Does car have a CE light?

__________________
A Dalton

Can I test the ECT sensor with a ohm meter?

Good suggestion. I will try that tomorrow.

On this car, the only pins that can be read using the code reader is 8, 14. Does pin 6 test for anything? I got 1 flash.

SRS -N/2 module
1 flash is no codes

__________________
A Dalton

Thanks, Arthur for the tips.

I tested the ECT sensor and it apprears to be good (250 ohms at 60 degrees).
The connector has 3 holes and only 2 holes with wires connected to it. The 2 wired holes tested negative for a short so insulation must still be good for now.

My problem was that the 2 wired holes were not connected to the pins on the sensor. It is easy to line up the wrong holes to the pins. I reattached the sensor correctly and reset pin 8 with the code reader. Hopefully, tomorrow the cold start and stumbling go away.

I spoke to soom. Problem did not go away. When testing pin 8 with the code reader today, I still get 2 blinks which indicates a problem with the ECT sensor.

The ECT tested fine. 250 ohms at 85 C and 1200 ohms at 25 C. I cleaned the connctors and pins.

Does anyone have a wiring diagram and let me know what is conncted between ECU and ECT sensor? Does anyone know what triggers a ECT sensor fault. Does the ECU compare the ECT sensor with another component to determine if the ECT sensor is good?

ECT sensor B11/3 is wired directly back to HFM/SFI N3/4 modules pins #28 & #36.
Sensor is monitored for short or open circuit.
R value comparison was not until '95 E320 version.
Suspect is harness.

__________________
A Dalton

Arthur, many thanks.

Cold start problem resolved. I opened the wiring sheathing to the ECT sensor and insulation toward the end of the connectors was disintegrated and bare. I taped up the bare wires and the car now starts fine.

So if anyone has unexplained codes and the sensors are fine, cut open the wiring harness and check it.

You need a Wire Harness.

__________________
A Dalton