103 engine coolant temp sensor
 

Have replaced this on my 91 300TE with 103 engine and 4 pole engine coolant temp sensor.

The plug has a flattened edge and the holes in it are marked 1 2 3 and 4. However, the sensor has no flattened edge nor markings, nor did the old one removed.

I've plugged it in has it naturally sits, but rough idle for engine. Other than keep turning the plug 90 degrees and driving the car around, anyone alligned up the sensor and plug correctly?

Thanks.

I was curious about this one too...

I turned it 90 degrees one way, and that did not make a difference in how the engine ran or code pulled. It is very stiff to turn any further.

I am getting Diagnostic code (at pin 6) #8 Engine temp sensor open circuit. Engine had developed rough idle, slightly higher than normal idle, and lower gas mileage. Pulled codes, and replaced the sensor. I cleared, and still get the code both ways the plug is attached.

Also pulling on pin 14 CC/ETA, #11 closed throttle recognition signal to ECM, and #13 Left EA/CC/ISC actuator right cylinder bank.

It does not matter which way you attach the plug. There are two identical sensors inside that unit, and they are wired kitty-corner. So, all you do when you flop the wire 90 degrees is switch which system reads which sensor. Since they are identical sensors, unless one is malfunctioning, swapping will not produce any change in behavior or symptoms at all.

If you're getting an open circuit error, double check the sensor itself - IIRC, you should get 2.2k-2.8k ohms between the pins (diagonally) @ 68degF.

If you've got that, you've probably got a break in the wiring from the sensor to the controller or the contact points in the connector itself are corroded.

Multiple codes could also be a bad ground...

Excellent- it is a new sensor, I will check it's resistence, I did clean the contacts in the plug with contact cleaner, and will check continuity for each of the four wires.

Thanks, Dave

I think the bad ground or wiring is a good suggestion. Is it possible it's the other temp sensor that's causing the code?