check engine code reads Catalytic running too cold and engine running too cold. on 2005 Nissan Sentra

my mechanic says it might be that since the thermostat may be stuck in open position, the catalytic converter may not be registering hot enough to work effectively. Is this possible??

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1 answer 1 comment
90% it's a stuck open thermostat. Have the mechanic plug in the scanner and see what the coolant temperature is getting up to. Should be above 190 degrees while driving.
Thank you! I'll have him check it and let you know! Thanks, again. ~ Dennis