Cadillac Repair: heater related, mass air flow sensor, mass air flow

Question
I have a 2000 Cadillac sts, just recently the heat has seemed to not be as hot. The temp gauge on the dash is below normal operating range, and the "flap" or diverter in the air trunk doesn't allow air to come out from the dash vents anymore. Thinking this is a heater core or vacuum problem. Temps in are area have been 0 and with wind chills -0 I even stuck a piece of cardboard in front of the radiator to see if a temp change would occur, but has not The check engine light came on and I have had it scanned and that is related to a bad mass air flow sensor, but this seemed to happened right after, not at any way connected?

Answer
Hi Tim,

    You could have several issues going on here. The first thing to do is make sure the coolant in the overflow tank is at the propper level and add if needed. If it is ok then change the thermostat and see what happens to the heat. That might be all that is needed there.

     As for the airflow issue an electric motor could be malfunctioning and by removing the panels under the dash and operateing the air from the floor to the vents to the windshield you should be able to see what motor isn't working. Sometimes those motors can be a charactor builder to replace so a trip to your mechanic might save some sanity.

    When I left the Caddy dealer in '99 the '00 Devilles were just comming out and they had a problem with the mass airflow sensors in that they were setting false codes. There might have been a PCM update calibration to get rid of the false MAF code that might help yours. Otherwise removing the sensor and cleaning the 3 small wires/sensors inside might help. They make a MAF sensor spray. The thing you don't want to do is touch those small wires/sensors or they could break...just use the spray on both sides. Otherwise there could be a problem with the sensor itself and need to be replaced or the wiring and PCM needs to be checked and tested with a scan tool and DVOM.

     Hopefully I have answered your question. Bill