'84 Cadillac Coolant temp sensor circuit

Hi All!
I have a '84 Cadillac Fleetwood. It has trouble code 15. "Open Coolant Temperature Sensor circuit". The BCM test 0.4 show -38 celsius for the coolant temp.
Is it possible the car hitch during driving because of the CTS? The choke is working always. Off course the a car "think" is it cold. I stop the engine when it is warm, the restart is very difficult... Is it depends on the CTS???
Thanks! Sands
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Sands wrote:

Yes. I suppose so or it could be the torque converter lockup.
" The choke is working always" What R E talking about?
Yes.
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The choke works when the engine is warm. I suppose, because the car "thinks" the engine is cold. CTS send wrong values to the ECM! Maybe...
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Since the CTS is 'open', the ECM is using the MAT sensor for input, which is probably why the engine is performing like it is. It could be a faulty CTS but first; check all wiring connections! Bad/loose/corroded/faulty mating are the things to look for in this circuit. There are some electrical tests that can be done but you'd need the diagnostic 'ladder' to follow. Do you also have a E21 code? If it turns out to be a wiring problem, be sure to clear the code afterward.
Dave S(Texas)
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Good info, right on target, Dave S, this is Dave S in NY!!

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Hi All!
It was the CTS bug. A replaced that and now everything is great! Thanks for all!
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