ECT sensor

Can a coolant sensor go bad but the ecu still get a reading? My cel popped on today for what I assumed was a intermittent P0420. But it was a P0115 instead. I have a scan gauge and it still read the coolant temp as normal. Nothing weird there. My gauge has always been jacked up on the cluster, and the sensor that reads it has been unplugged for years with no issue. My truck uses 2 sensors one for the gauge and one for the ecu.

 

It's possible. Do the readings seem normal for am operating engine temp? 190 to 200 degrrees.

 

there are 2 engine coolant temp sensors, one for the temp gauge in the combination meter and one for the fuel injection. The fuel injection temp sensor is usually a 2 wire sensor whereas the gauge temp sensor is one wire. Which one is your scan gauge reading not 100% sure but I would suspect the 2 wire one via the PCM.

 

Have you checked connection and wires at ect sensor?

 

Yes, the scanguage reads the pcm as it's plugged in directly to the obd2 port. It reads temps as normal, 185-193ish. I cleared the code and it comes right back within a minute. The 2 wire up front reads the pcm, wires and plugs all look normal. I just assumed if there was an issue it would run bad or the temp would be way high or way low on the scan guage... It the factory sensor it appears.

 

To set that code the ecm sees an open or short for 0.5 seconds. Possibilities are the sensor, the wires or the ecm.

 

I’m gonna order a new one and go from there.