Is the coolent sensor self grounding? I just installed this engine, and wrapped my used/old coolent sensor with tuflon tape, and now its throwing a code.

What are the odds that if I take the tape off, it will work fine again, or just luck happens it broke at this same time?

 

No. There is a grounded conductor provided at the connector for the CTS.

Make sure you have the correct sensor. There may be as many as three coolant temperature sensors on your engine - One for the dash gauge, one for the radiator auxilliary cooling fan, and one for the ECM reading of engine coolant temperature. The one for the ECM typically has a black (grounded) and yellow (signal) wire in the connector. As I recall, neither of the other two sensors should have a two-wire connector. Also, failure of either of the other two sensors will not set an error code.

You may also simply have a failed sensor, or a poor engine ground for the ECM wiring harness (often at the right rear corner of the intake or rear of the right head).