Lake Runner

Trying to diagnose a temp sensor issue, P0118 code with .1-.2 volts at terminal. Need to test for a short or open circuit .What are the pin locations at the ECM for the sensor wires?
Any help would be appreciated. I had replaced t-stat and sensor twice since this started(before an ECM replacement which cleared up other issues). From what I can find the sensor wires are not on
the 58 pin connector on the ECM.

Oldblue

I just replaced the connector, like this pigtail, problem solved

donbrew

signal/5 volt is the yellow wire on pin #50 and tan on #61 is low ref. That probably explains the odd looking voltage readings.

P0118 is "ECT sensor circuit HIGH voltage". Which means a low temp reading.

Oldblue

Maybe a good burp will help!

https://www.chevyhhr.net/forums/how-...-system-60614/

possibly an air pocket in the cooling system

RJ_RS_SS_350

What thermostat did you put in?

Lake Runner

I put in a Mahle t-stat. OBD2 codes remain P0118 after code is cleared and sensor disconnected and cleared then after connected. Low voltage at the terminal suggest to me that there is a break or short in the wiring.

Lake Runner

The Mahle replaced an Autozone Duralast that was installed in 2013, 177k miles ago.

donbrew

So, all of my work is invisible?

RJ_RS_SS_350

Try the ACDelco 131-158 thermostat.

Lake Runner

Don, I'm not sure what you mean by invisible. I read your reply and have checked and reset the code several times.
The code always comes back the same P0118. It will do this with or without being connected. There is minimal voltage at the pigtail(0.1-.02 volts)
I would like to check the connector pins to the pigtails to see if there is an open or shorted condition in the wiring. At first, this problem was intermittent , and now it is constant.
Would you happen to have a picture or diagram of the pin layout or location as there is only one number(53) on the upper ECM plug. Trying to locate pin 50 and 61.
All help is appreciated.