fotomoto Posted June 24, 2013 Report Share Posted June 24, 2013 (edited) OK, I know we Texans have been know to tell a tall tale or two but I've got pics to prove it! :) Then a few minutes later, the mother of all blizzards fell upon me: and finally while checking things in the settings menus it does this: I'm going to perform a master reset and see if this resolves the OAT readings. I have 3.5.1 from the factory. Edited June 24, 2013 by fotomoto Quote Link to comment Share on other sites More sharing options...
Jus-A-CMax Posted June 24, 2013 Report Share Posted June 24, 2013 Adair...Please come and collect your Aliens Quote Link to comment Share on other sites More sharing options...
Adair Posted June 24, 2013 Report Share Posted June 24, 2013 My aliens might do the +167 but NEVER the -40. They know better! Quote Link to comment Share on other sites More sharing options...
SnowStorm Posted June 24, 2013 Report Share Posted June 24, 2013 fotomoto - Are you the guy that removed your right side mirror? Looks like a bad connection to the sensor - jerking it one direction or the other. The numbers are -40 to 75C, probably the limits in the software, and then --- when it decides "bad sensor". Hope it's easily fixed! Quote Link to comment Share on other sites More sharing options...
Jus-A-CMax Posted June 25, 2013 Report Share Posted June 25, 2013 I think that was Matt who removed his mirror...could be wrong. fotomoto...that is plain bizzare, sorry not much of a help other than make you smile ;) Quote Link to comment Share on other sites More sharing options...
fotomoto Posted June 25, 2013 Author Report Share Posted June 25, 2013 fotomoto - Are you the guy that removed your right side mirror? Nope, not me. Was that ever determined to be the temperature sensor on the bottom? The master reset didn't cure it. :sad: I'm sure it's related somehow as now the HVAC system has gone bananas (technical term). In auto mode set to 74F, it switched to floor vents and heat! The a/c compressor and fans were both off. I switched to manual and dash vents only to get warm air out of those. Eventually a couple of power on/off's and setting it to max a/c got it working again. About an hour later in the garage, I went to pair my phone which had been lost to the master reset. Same things happened again. I checked under the hood to hear only silence from the compressor and fans. This morning it was fine and the OAT was just a few degrees off actual. <shruggs> Quote Link to comment Share on other sites More sharing options...
ceemax71 Posted June 25, 2013 Report Share Posted June 25, 2013 (edited) The outside air temperature sensor is definitely in the passenger side rear-view mirror.The OAT sensor is actually wired to the power train control module and is used by several different control modules as well as HVAC.If the OAT sensor or related wiring is bad, I would think that you would be getting some type of diagnostic fault code. Edited June 25, 2013 by ceemax71 Quote Link to comment Share on other sites More sharing options...
plus 3 golfer Posted June 25, 2013 Report Share Posted June 25, 2013 The ambient air temperature sensor is in the RH mirror (passenger side). I assume it's the little nub projecting from the bottom of the mirror. The sensor is connected to the PCM. Generally, when a sensor fails, the control algorithms use backup values as a proxy for the failed sensor although this may not have a backup but likely is the backup should the engine intake air temperature sensor fail. You may want to test with some ice on the nub and see how the temperature behaves. There may even be some test screens in the MFT (note: I need to again find how to enter the screens and put in glove box so I don't forget). The fact that the temp swung to extremes suggests that the sensor resistance went from infinite (open circuit - low reading) to zero (short circuit - high reading). It looks like P0072 and P0073 are DTC for Low / High ambient air temps which may be in the MFT test screens or perhaps in the Engineering Test Mode (IIRC do show DTC) since these are Powertrain Codes. Quote Link to comment Share on other sites More sharing options...
SnowStorm Posted June 25, 2013 Report Share Posted June 25, 2013 I tried holding my fingers and then a hot rag on that nub but could never get the OAT reading to change. This was in the garage with the car on (didn't try it while driving!). It seemed like the value was "frozen" as it was certainly reading different from the temperature in the garage at the time. Yet when driving it seems to work fine. So I don't know if the sensor is in the nub or not. (Or if the value gets "latched' until a certain point after you start driving or what.) Quote Link to comment Share on other sites More sharing options...
Napa Jeff Posted February 27, 2015 Report Share Posted February 27, 2015 I have a 2014 C-Max that has started having the same problem this evening. Less than 7K on odometer. Back to the shop AGAIN! I'm howling at everyone that will listen about what a bad purchase it was. Quote Link to comment Share on other sites More sharing options...
Adrian_L Posted February 27, 2015 Report Share Posted February 27, 2015 (edited) I have a 2014 C-Max that has started having the same problem this evening. Less than 7K on odometer. Back to the shop AGAIN! I'm howling at everyone that will listen about what a bad purchase it was. Frustrating. Hopefully it's just a sensor to be replaced and you'll be able to enjoy getting to know your car and it's unique qualities. Welcome to the Forum. Edited February 27, 2015 by Adrian_L Quote Link to comment Share on other sites More sharing options...
fotomoto Posted February 27, 2015 Author Report Share Posted February 27, 2015 As the OP of this thread, I should follow up that it never happened again nor did I have it looked at. Quote Link to comment Share on other sites More sharing options...
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