Just had a new crate motor installed and I'm now having engine coolant sensor error codes. Installed new sensor and still didn't fix the problem. With the sensor plugged in, the engine idles down and dies. unplugged it idles fine. This is on a 2001 regular Cherokee 4.0 inline engine. Replaced the engine idle air module as well. Checked the wiring for proper grounding and it checked out. Any ideas? Codes PO117 or PO118.

 

Remove the ECT connector and examine the pin cavities in the connector for being pushed back in, or being enlarged.

Examine the wiring for chafing, broken, etc.

P0117 is an open condition, like unplugging the connectoor.

 

also check to see if the opening / threads have paint on them, preventing the sending unit from making a good ground connection

 

could also be a defective sensor. You can expose the business end of the sensor to hot/boiling water while measuring the resistance and see if it changes as the temp goes up/down.

 

^^^ great suggestion