37500 miles

Two days ago the car popped up the MIL on the dash. Read the DTC and it was PO128 (Coolant Thermostat-Coolant below regulating temperature). This occurred about a day after I degreased and water washed an oily connection to the A/C condenser on the passenger side of the car. The ETC sensor is driver side radiator bottom. Was able to remove the connector on the ECT sensor and jiggled it back on to hopefully make a better connection. From what I've found from Google searches this connector has an issue with corrosion due to it's location. Subsequently I reset the DTC to see if it would return. After taking the car out twice a new code returned, this time PO2183 (Engine Coolant temperature Sensor 2 circuit range/performance).

Got the meter out this morning and did some measurements....
- With car running approximately 4.4-4.6vdc at ECT connector and stable if wires were jiggled.
- At pins of the ECT sensor about 70 deg F, 3500 ohms. (found a graph on this site and if it applies to this year, the resistance seems in the ballpark). Didn't attempt a warm up of the car as I was looking for either an open or a short and figured having some resistance indicated a non-failure.

The connector did appear to have some corrosion. Cleaned with a wound guitar string and DeOxit contact cleaner. The pins I couldn't see well, bit I used a small alligator clip to scrape them a bit.

I haven't taken the car out as of yet or reset the DTC. Wondering if everything I did seems in the right direction and is there something else I should look at.

One other thing.... will a DTC reset itself if all is good after a few trips out or does this need a reset from my reader?