check engine light stays on even when codes clear/ except collant temp code keeps coming up

1995 CHEVROLET IMPALA
V8 • 2WD • AUTOMATIC
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TOPCAT
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used a diagnostic machine keeps saying coolant temp is -41 check engine light stays on even when you reset codes car is a 1995 Impala, changed collant sensors three times from different auto shops(Car Quest, O'riley,NAPA)is there any other sensor that I need to change out?
Jun 12, 2012 at 6:25 PM
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CARADIODOC
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Codes never say to replace parts. They only tell you which circuit needs further diagnosis. -41 indicates there is an open circuit in the wires to that sensor. The sensor itself is the least likely suspect.

Start by inspecting the connector terminals for corrosion and to be sure they're not stretched or deformed. Next, measure the voltages on the two wires, first by back-probing them through the rubber seals with the connector plugged into the sensor. If you find 0.0 volts on both of them, double check by unplugging the connector and touching the meter probe right to each terminal, one at a time. If you still find 0.0 volts on both wires, the 5.0 volt feed wire is open.

With the plug still connected, if you find 5.0 volts on both wires, the ground return wire is open.
Jun 12, 2012 at 6:55 PM
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