temperature gauge inaccurate or failure?

[viciousvîc]

I read older thread on false temperature reading, is this a sending unit failure? a grounding connection situation? ?? Is this what leads to thermostat housing breakage and OEM aluminum housing replacement part? How common is this problem in 1.6 ECO-TECH II engine or temp gauge failure? I understand false temp signal cud lead to ECU trying to compensate for -40* temp, when actual temp is normal. over RICH/LEAN condition could cause catastrophic engine failure. recreate my 1hr drive commute condition today; everything normal, temp just below halfway and steady, not normal was AC temp went from 35* to steady 68* after 30 minutes into commute as I had thermometer in center vent still from recent freon service couple weeks ago. Everything seemed normal after arriving home a few minutes later, after noticing gauge reading showed typical off/cold position, a few minutes ago. No sign of over heating or excessive fuel burning. Aveo has been running like well oil japanese crotch rocket. plan on code checking in morning, and then will procede accordingly. Hoping for simple gauge failure, sending unit failure or simple ground connection. I will intertain all diagnosis from all members who can send me down rabbit hole thru deduction and/or investigative reasoning. only found 1 thread for temperature gauge false reading. so not much for commonality situations. suggest all read it, this has potential to be very serious situation, turning into catastrophic engine failure, if ignored for short time frame. Thanx to all who can contribute any thots to this/my situation, much appreciated. Have Nice Day..

[viciousvîc]

coolant temp code this morning , 45v guessing the ECU thinks its in north pole. no AC. going to drive to work n moniter realtime readings. safe or not. possible to clear code n get AC back running ? got new thermostat ordered be here end of week. will update daily if possible , thanx

[viciousvîc]

well, made it to work without incident . temp maintained 168* , so thermostat must be stuck open, thats a good thing. Wondering now how much resistance is needed for AC to come back alive, wud a 1156 bulb create enough resistance? unplug temp sensor n wire up bulb...worked on VW alternator n my jeep alt. also, acts like a oneway valve. just a thot.

[viciousvîc]

well, made it to work without incident . temp maintained 168* , so thermostat must be stuck open, thats a good thing. Wondering now how much resistance is needed for AC to come back alive, wud a 1156 bulb create enough resistance? unplug temp sensor n wire up bulb...worked on VW alternator n my jeep alt. also, acts like a oneway valve. just a thot.