Where is the temp. sender located ??

[Doug Doty]

My car once before give an overheating message on the DIC but was confirmed to not be hot and the problem went away after the 2nd. restart. Now it has came back and is persistant. It cycle tests the gauge on startup and imeadiately tells me " engine hot, A/C off " I am thinking it needs a new sending unit. I was just hoping it was in some accessible location. Any opinions.

Doug...

 

[TED]

I beleive there are 2 One for the gauge and one for the computor.

 

[Doug Doty]

I should have mentioned that the electric fans come on as soon as you start the car as well, even on a cold start.

 

[Cadillac Tech]

It is on the rear of the passenger side or right cylinder head. You may need to remove the intake manifold to gain access to the sensor.

 

[Doug Doty]

Do my symptoms seem as though I am on the right track

 

[Johnxlrv]

Hope it is easier to find the sensor unit

Just started seeing this issue...after checking belts, coolant level and running heater full blast for a short trip (which indicated coolant circ.), I believe I now have this same issue. Interesting that it occurred after letting the battery run down...after recharging, this issue surfaced. With two sensors, I am at a loss...temp gauge cycles and stays low...radiator fan runs high and AC remains off...it is not overheating basis expected oil pressure and the lack of discoloration or excessive pressure on the coolant reservoir.

...Just wishing there was a magic reset lol...

 

[V Happy]

Johnxlr
I would give it a few runs if you are sure it is not overheating. Did you add any Coolant on the check ? Computer may need to see a few starts without overheat code. These cars do some strange things when battery is left depleted. If it continues after a few runs repost. You are adding to a very old post.
V Happy

 

[onalaska]

Just started seeing this issue...after checking belts, coolant level and running heater full blast for a short trip (which indicated coolant circ.), I believe I now have this same issue. Interesting that it occurred after letting the battery run down...after recharging, this issue surfaced. With two sensors, I am at a loss...temp gauge cycles and stays low...radiator fan runs high and AC remains off...it is not overheating basis expected oil pressure and the lack of discoloration or excessive pressure on the coolant reservoir.

...Just wishing there was a magic reset lol...

I had this same problem a few years back and the temp sending unit checked out fine. It turned out the thermostat was bad and causing the problem. It was stuck open, yes open, and the engine was not warming up as fast as the computer expected it too. The message "engine hot A/C off" is shown on the DIC and it runs the fans on high. You would think it would be the opposite and that the thermostat was stuck closed, but the engine was not hot at all. I think the software was programmed incorrectly and delivers the wrong message on the DIC. Anyway replacing the thermostat fixed mine. It's a simple job on a XLR-V. Here is the info from my notes back in 2013 when it happened.

"DIC displayed Engine Hot - A/C off after abt 5 miles. Engine was not hot, but suspected thermostat and after message went away engine was slow to warm up. Replaced thermostat with Duralast 4228 and Felpro 35660 gasket. Topped off coolant."

 

[xlrlist01]

I had this same problem a few years back and the temp sending unit checked out fine. It turned out the thermostat was bad and causing the problem. It was stuck open, yes open, and the engine was not warming up as fast as the computer expected it too. The message "engine hot A/C off" is shown on the DIC and it runs the fans on high. You would think it would be the opposite and that the thermostat was stuck closed, but the engine was not hot at all. I think the software was programmed incorrectly and delivers the wrong message on the DIC. Anyway replacing the thermostat fixed mine. It's a simple job on a XLR-V. Here is the info from my notes back in 2013 when it happened.

"DIC displayed Engine Hot - A/C off after abt 5 miles. Engine was not hot, but suspected thermostat and after message went away engine was slow to warm up. Replaced thermostat with Duralast 4228 and Felpro 35660 gasket. Topped off coolant."

No it isn't programmed incorrectly. On-board diagnostics all have the exact same problem, it never can identify what is wrong with 100% certainty. What happens it that readings and values are out of specification. Based on that the PCM takes a worst case scenario guess and (in this case) goes for a sensor failure. If the sensor has failed there could be an over-heat situation, so that is what gets reported. The diagnostics are very, very good, but they are not psychic, so when trying to work out what is the actual fault it is necessary to take into account all symptoms, which a good tech will ask you for.

 

[TED]

Just started seeing this issue...after checking belts, coolant level and running heater full blast for a short trip (which indicated coolant circ.), I believe I now have this same issue. Interesting that it occurred after letting the battery run down...after recharging, this issue surfaced. With two sensors, I am at a loss...temp gauge cycles and stays low...radiator fan runs high and AC remains off...it is not overheating basis expected oil pressure and the lack of discoloration or excessive pressure on the coolant reservoir.

...Just wishing there was a magic reset lol...

XLRlist01 Is Correct. The thermostat is a fail safe and stuck open! Change it ,get all the air out , erase the code, Enjoy

 

[Big Duck]

Problem is stuck thermostat.

Just had same problem yesterday and indeed it means the thermostat is stuck OPEN.