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coolant temperature sensor is sending high voltage code


underthesun1020

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I have a 2000 deville dts with the 300hp motor and i just had it replaced and the only code it sends is a p0118 code that is cts high voltage. Has anybody heard of this problem and how do i fix it, by the way the gauge in the cluster isn't reading anymore it just stays on cold. I replaced the sensor but it is still doing the same thing. can anybody weigh in on this.

thanks

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When you replaced the sensor, did you double check the connector on the chassis wiring? And double check the remainder of the harness that goes to the PCM?

With an engine R&R there is a chance the wiring is pinched or otherwise damaged. The high voltage code usually means the circuit is open somewhere.

Jim

Drive your car.

Use your cell phone.

CHOOSE ONE !

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A high voltage reading on the engine coolant temperature sensor usually means that it is disconnected. See if there is any voltage on the terminal at the sensor with the engine off, key on. If not, work bacward for an open circuit, which would be a loose connector or wire pulled partly or completely out of a connector, a cut or broken wire, etc.

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It is possible your "new" sensor is also failed.

You should read some value of resistance across the sensor terminals; can't give you a value as it depends on temperature and I am unable to find a resistance vs. temperature chart for the sensor.

If the sensor resistance changes when you change the temperature of the device, it is most likely working as intended. Guessing here, but if I saw resistance in the range of 500 Ohms to 3,000 Ohms, I would assume the sensor is not the problem.

That leaves the connector(s) at the PCM. My wiring schematic says the ECT sensor is across PCM C2-18 and C2-33.

Jim

Drive your car.

Use your cell phone.

CHOOSE ONE !

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