Coolant Temperature Hot

2002 BUICK RENDEZVOUS
130,000 MILES • 3.4L • 6 CYL • AWD • AUTOMATIC
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DREV0012
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Hi, I have had a Coolant temperature hot light that has come on a couple times in the last week. The light comes on, car dings until turned off. Each time, after turning the car off and turning it back on, it did not come back on. There were four days between the first time it happened and the second. I scanned the computer and had a few codes, but none seemed to be correlated with the temperature that i am aware of. Both fans appear to be running. Thermostat was replaced a couple years ago. These are the codes I received:

P0463 - Fuel Level Sensor A
Circuit High Input

P1189 - Engine Oil Pressure
(EOP) Switch
Circuit

P1811
Maximum Adapt And Long Shift

U1064
Loss of Communication with Body control module.

Thanks for the help!
May 10, 2016 at 5:17 PM
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HMAC300
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try replacing the switch on engine it may be bad and look for wire grounding out on engine. also check battery for condition including load test it may be that.
May 11, 2016 at 9:38 AM
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RENEE L
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Hi DREV0012,

Here is a link to an article form this site that features written instructions, pictures and a video explaining how to load test your battery yourself. Thank you for visiting 2CarPros.

https://www.2carpros.com/articles/how-to-check-a-car-battery

Kindest regards,

Renee
May 11, 2016 at 4:26 PM
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DREV0012
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Would a bad battery cause the coolant temp light to come one?

Do you have any good instructions for replacing the switch? I know the thermostat is a bear to get at in this vehicle and wondering if the switch is extremely involved. Thanks!
May 12, 2016 at 10:15 PM
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SATURNTECH9
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Just too add to this one does the temp gauge showing its overheating when the hot light comes on?Also the p1811 is almost always a bad line pressure control solenoid.If you drive it too long with the bad solenoid you destroy the transmission.Also the fuel level sensor code is a bad fuel sending unit.We don't have videos for each make model of cars for replacing different cars.I would suspect the coolant temp sensor.I'd your code reader will read live coolant temp data?you can use a infrared temp gun to compare it to what the sensor is reading to see if it's good.
May 15, 2016 at 11:18 AM
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SATURNTECH9
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As far as the oil sending unit you just unplug it and get a oil sending unit socket and unscrew it and screw the new one in.Usually when the thermostat goes bad on those it sets a code P0128.
May 15, 2016 at 11:33 AM