Where is the Engine Temperature Sensor located?

2011 CADILLAC CTS-V
36,000 MILES • V8 • 2WD • AUTOMATIC
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TIMBURNS15330
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First of all, this is a custom built restomod of a 1938 Cadillac. It has a all new custom frame, suspension, rearend, etc. And it has the engine from a 2011 CTSV. I have a stand alone wiring harness made for this engine from PSI. When I start the engine, it is difficult to start and the engine runs rough and smokes. When I put a scanner on it, no codes are thrown, however, the Engine Coolant Temp shows -40. From what I understand, that could be causing my issues. However, I'm not sure which sensor is the engine coolant sensor. Based on the harness, what I thought was the ECT sensor has three wires and three pins. So, I don't think that is correct. There's another two pin sensor that I thought might be the ECT sensor, but when I bought a new sensor, although it kind of fits, it doesn't snap on to the harness. So, I don't think that's correct either. My question is, where is the temperature sensor on my 2011 Cadillac CTSV engine?
May 23, 2025 at 2:23 PM
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STEVE W.
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-40 on a temperature sensor is normally an open circuit. It is a 2-pin thermistor circuit, A Yellow and a Tan the Tan is sensor ground and Yellow is the signal. The sensor is in the front corner of the left-hand head.
May 23, 2025 at 4:58 PM
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TIMBURNS15330
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Steve, you’re a genius! Thank you! I did find it. The guy who put my PSI harness had the connector for the temp sensor connected to the evap solenoid. Its kind of fit and I never questioned it. After your post, I traced it down and connected it to the temperature sensor and the engine runs fine! But the oil smells like gas, so another oil change is in my future. Thanks again!
May 24, 2025 at 4:07 PM
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STEVE W.
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Glad to hear you found it. Yeah, if it smells like gas it's got to go. You are welcome.
May 25, 2025 at 6:19 AM