Having problems with your Cadillac DeVille ?
P1258 engine metal over temperature protection- is it the thermostat ,and if where is it located?? Thank-you.
Some Cadillac motors use a sensor called an engine metal temperature switch. This switch is usually located on one of the cylinder heads and normally has a one wire connector. It is small and can be difficult to locate. When you find it , try disconnecting it. If the problem goes away then the switch is bad. Be aware that the check engine light will probably come on if it isn't already and that this procedure may not work because it may need to be in the circuit for the system to operate. Good luck!
Repair Help & Product Troubleshooting for Cadillac DeVille
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