denizli escort bayandenizli escort bayandenizli escort bayandenizli escort bayanantakya escortantakya escortantakya escortiskenderun escortiskenderun escortiskenderun escorteskişehir escorteskişehir escortdenizli escortdenizli escortdenizli escortdenizli escortdenizli escortdenizli escortdenizli escortdenizli escortdenizli escortdenizli escortdenizli escortdenizli escortmalatya escortmalatya escortgaziantep escortgaziantep escortgaziantep escort

izmir escort

antalya escort

izmir escort

porno

porno izle

bursa escort

escort

mobil porno

havalandirma sistemleri

antalya escort

takipçi satın alma

instagram beğeni hilesi

instagram takipçi hilesi

saha betonu

izmir escort

eskişehir escort bayan

takipçi al

beğeni al

takipçi satın al

beğeni satın al

Ambient temperature sensor failure
500 Madness
  
DiCorse
      
Page 1 of 2 1 2 LastLast
Results 1 to 10 of 11

Thread: Ambient temperature sensor failure

  1. #1
    Member
    Join Date
    Jan 2021
    Location
    Alabama Gulf Coast
    Posts
    39
    Thanks
    1
    Thanked 33 Times in 16 Posts

    Ambient temperature sensor failure

    Today I got a check engine light caution in my 2015 Fiat 500 Abarth. When I got home I read the code which showed a failure of the ambient temperature sensor, the one in the passenger's side mirror. I was able to reset the code, but the temperature reading shows 104 degrees F, which is obviously wrong. So I ordered a 10k thermistor and I'll repair the sensor when the part arrives.
    When I had the diagnostic equipment connected I took a look at the intake manifold temperature and it showed 82 degrees, which seems about right.

    I read somewhere that the ambient temperature is one of the parameters read by the ECU and if the reading is way out of wack, it could effect the fuel/air ratio. Of course, since the information came from the Internet, who knows how true it may or may not be.

    It seems to me that if the car knows the intake temperature, it would not really care about the outside air temperature when it comes to engine operations, fuel/air ratio, etc. My guess is that the ambient temperature is posted on the dash strictly for driver's information and may, perhaps, help predict ice on the roads, and so on. Of course, that's just a guess too.

    Does anyone really know what the ambient temperature sensor does other than simply display the outside air temperature for the education of the driver? Is it really an input for the ECU as well? That makes no sense since there is an intake manifold temp. sensor. And why if it simply indicated temperature for the driver's information, does it turn on a check engine light with a suggestion to take your car to be serviced? I know a lot of people who might immediately shut off the car and pay for an expensive tow when the check engine light illuminates, which in this case would be a real disappointment.

    What's the deal? Does anyone really know?

  2. #2
    Amministratore Fiat500USA's Avatar
    Join Date
    Feb 2011
    Location
    New York
    Posts
    13,382
    Thanks
    7,877
    Thanked 6,914 Times in 4,105 Posts
    Quote Originally Posted by Mozella View Post
    Today I got a check engine light caution in my 2015 Fiat 500 Abarth. When I got home I read the code which showed a failure of the ambient temperature sensor, the one in the passenger's side mirror. I was able to reset the code, but the temperature reading shows 104 degrees F, which is obviously wrong. So I ordered a 10k thermistor and I'll repair the sensor when the part arrives.
    When I had the diagnostic equipment connected I took a look at the intake manifold temperature and it showed 82 degrees, which seems about right.

    I read somewhere that the ambient temperature is one of the parameters read by the ECU and if the reading is way out of wack, it could effect the fuel/air ratio. Of course, since the information came from the Internet, who knows how true it may or may not be.

    It seems to me that if the car knows the intake temperature, it would not really care about the outside air temperature when it comes to engine operations, fuel/air ratio, etc. My guess is that the ambient temperature is posted on the dash strictly for driver's information and may, perhaps, help predict ice on the roads, and so on. Of course, that's just a guess too.

    Does anyone really know what the ambient temperature sensor does other than simply display the outside air temperature for the education of the driver? Is it really an input for the ECU as well? That makes no sense since there is an intake manifold temp. sensor. And why if it simply indicated temperature for the driver's information, does it turn on a check engine light with a suggestion to take your car to be serviced? I know a lot of people who might immediately shut off the car and pay for an expensive tow when the check engine light illuminates, which in this case would be a real disappointment.

    What's the deal? Does anyone really know?
    Here are a few posts with info taken from the repair manual. The last post is a little ambiguous.


    Quote Originally Posted by Fiat500USA View Post
    Hi Jim,

    The ambient air temperature sensor sounds like it needs to be checked. Here is how it works:

    The ambient air temperature sensor is a variable resistor that monitors the air temperature outside of the vehicle. The Automatic Temperature Control heating and A/C system uses the ambient temperature sensor data to maintain optimum cabin temperature levels. The ambient air temperature sensor is that little bump that protrudes on the bottom of the right outside rear view mirror. The dealer uses the scan tool to diagnose it.



    Source: FCA US LLC
    Quote Originally Posted by Fiat500USA View Post
    Some info on the P0073 code.

    The Heating, Ventilation, and Air Conditioning (HVAC) module receives the information about outside temperature to carry out the correct air mixing strategies from the Body Control Module (BCM) via Controller Area Network (CAN). The ambient temperature sensor is positioned in the right door mirror and it is managed by the BCM, which also receives the sensor’s temperature information.

    P0073-AMBIENT AIR TEMPERATURE SENSOR CIRCUIT HIGH

    When Monitored:

    This diagnostic runs continuously when the following conditions are met:

    • With the ignition on.
    • Battery voltage greater than 10.4 volts.


    Set Conditions:
    The Powertrain Control Module (PCM) detects that the Ambient Air Temperature Sensor input voltage is above the maximum acceptable value.

    Default Actions:
    The MIL light will illuminate.

    Possible Causes

    • AAT SIGNAL CIRCUIT SHORTED TO VOLTAGE
    • AAT SIGNAL CIRCUIT OPEN/HIGH RESISTANCE
    • AAT SENSOR GROUND CIRCUIT OPEN/HIGH RESISTANCE
    • AMBIENT AIR TEMPERATURE (AAT) SENSOR
    • BODY CONTROL MODULE (BCM)
    Quote Originally Posted by Fiat500USA View Post
    The Fiat 500X thermostat is closed below 195F (90C).

    According to FCA
    The Thermostat is considered malfunctioning if the coolant temperature does not reach the highest temperature required to enable other diagnostics, or the coolant temperature does not reach a warmed up temperature within 11.0C (20F) of the Thermostat regulating temperature. The Powertrain Control Module (PCM) creates a model of the engine coolant temperature warm up cycle, based on the engine coolant temperature at start up, ambient temperature, vehicle speed and engine speed. The modeled engine coolant temperature is compared to the Engine Coolant Temperature Sensor reading. If the engine actual temperature reaches the calibrated temperature threshold before the model, the diagnostic passes and completes. If the model reaches the calibrated temperature threshold before the engine actual temperature, a pass/fail determination is made based on the difference between the model and actual values. The diagnostic is considered passing if the difference between the engine actual temperature and model is acceptable when the model is greater than the engine but represents the slowest possible warm-up for a “good” thermostat.


    The PCM runs this diagnostic when the following conditions are met: With the engine running. Start up coolant temperature less than 65C (149F). Ambient temperature between -8C (17.6F) and 50C (122F). Average vehicle speed greater than 16 km/h (10 mph) until coolant temperature reaches 85C. Engine speed does not go above 5400 rpm for more than 32 seconds. The pass/fail determination point is reached when the coolant temp model reaches 88C (190.4F).

    The MIL turns on when the predicted coolant temperature reaches the target threshold before the actual coolant temperature and the PCM detects that the actual engine coolant temperature is too far below the what is acceptable for a good thermostat.



    Possible Reasons

    LOW COOLANT LEVEL
    COOLING SYSTEM ISSUES
    THERMOSTAT OPERATION

    Here is how to test the thermostat



    • If the ECT is above 82C (180F), allow it to cool down to below 65C (150F) before performing this test.
    • For optimal results, allow the vehicle to sit outside for 8 hours before performing this test.


    1. Turn the ignition on.
    2. With the scan tool, monitor the Engine Coolant Temperature (ECT).
    3. With a thermometer, monitor the temperature directly downstream of the thermostat.
    4. Start the engine.
    NOTE: The ECT reading on the scan tool and the reading on the thermometer should be about the same after the thermostat opens. A discrepancy may indicate an inaccurate ECT Sensor signal to the PCM.
    5. As the engine warms to operating temperature, record the temperature at which the thermostat opens.
    6. Using the appropriate Service Information, determine the proper opening temperature of the thermostat.

    If the thermostat opened at the correct temperature you then check the ECT engine coolant temperature.


    description courtesy of FCA
    However, I read on the forum someone disconnected the sensor and they didn't mention any problems with running. http://www.fiat500usaforum.com/showt...rature-Display
    Last edited by Fiat500USA; 04-11-2021 at 10:15 PM. Reason: added some more info
    Enjoy the Forum, or has it helped? Please Whitelist us on your Ad Blocker. Thx!

    #modifiedabarth modifiedabarths.com

    abarth500forum.com fiat124spiderforum.com fiat500lusaforum.com fiat500xforum.com

  3. The Following User Says Thank You to Fiat500USA For This Useful Post:

    luckymoi (04-12-2021)

  4. #3
    Member
    Join Date
    Jan 2021
    Location
    Alabama Gulf Coast
    Posts
    39
    Thanks
    1
    Thanked 33 Times in 16 Posts
    Thanks for that info. It makes sense that the A/C system might have an input form the Ambient Temperature. As far as it having an input to the engine cooling thermostat, I had not thought of that. But it did not make sense to me that it would have anything to do with the fuel/air ratio and the information you supplied seems to support that idea.

    At any rate, cutting out the old thermistor and soldering in a new one for a dollar or so seems simple enough and is certainly better than paying more than a hundred bucks for a whole new mirror because someone at Fiat failed to include a connector for the thermistor.

  5. The Following User Says Thank You to Mozella For This Useful Post:

    Fiat500USA (04-12-2021)

  6. #4
    Moderator map's Avatar
    Join Date
    Dec 2018
    Location
    Eugene
    Posts
    2,195
    Thanks
    654
    Thanked 690 Times in 571 Posts
    I like your idea of replacing the thermistor. If you can locate one, try to find a +/- 1% model. I understand it's using the internal (mounted in the dash) and external temps to determine when to turn on/off the A/C; not sure if it affects when to open the heat flap. When the unit goes bad it usually reads higher than normal temps, but a couple 500e owners had them read low temps... and the reported A/C wouldn't come on. (That makes sense... why run A/C if it's 30 degrees outside.) It is also responsible for turning on the ice warning light.

    Several cars I've tinkered with had temp sensors low and near the grill. That area could become heat soaked on the 500... the mirror would be a more sensible location. I don't know if there's a second temp sensor near the throttle body intake. That would make sense to me but Fiat sometimes does things differently.

  7. The Following User Says Thank You to map For This Useful Post:

    Fiat500USA (04-12-2021)

  8. #5
    Amministratore Fiat500USA's Avatar
    Join Date
    Feb 2011
    Location
    New York
    Posts
    13,382
    Thanks
    7,877
    Thanked 6,914 Times in 4,105 Posts
    There is a Intake Air Temp Sensor built into the MAP sensor. Here's a post from a previous thread.

    Quote Originally Posted by Fiat500USA View Post
    The Fiat 500 Abarth combines the intake air temperature sensor and the MAP sensor into one unit (see below). Between that and the coolant temperature sensor, it is doubtful the PCM is using the ambient temp sensor in the mirror for engine operation.



    This sensor monitors both Inlet Air Temperature (IAT) and Manifold Air Pressure (MAP).

    The sensor is installed in the intake manifold with the sensor element extending into the air stream. The Intake Air Temperature (IAT) portion of the sensor is a two-wire Negative Thermal Coefficient (NTC) sensor. Meaning, as inlet air temperatures increase, resistance (voltage) in the sensor decreases. As temperature decreases, resistance (voltage) in the sensor increases.

    The Manifold Air Pressure (MAP) portion of the sensor provides instantaneous manifold pressure information to the Powertrain Control Module (PCM). The data is used to calculate air density and determine the engines air mass flow rate, which in turn determines the required fuel metering for optimum combustion.

    courtesy of FCA
    Enjoy the Forum, or has it helped? Please Whitelist us on your Ad Blocker. Thx!

    #modifiedabarth modifiedabarths.com

    abarth500forum.com fiat124spiderforum.com fiat500lusaforum.com fiat500xforum.com

  9. #6
    Premium Member Premium Member RexS's Avatar
    Join Date
    Aug 2018
    Location
    Williamsburg, Va
    Posts
    442
    Thanks
    139
    Thanked 181 Times in 117 Posts
    I just replaced the Ambient Temp sensor in my wifes 500 sport. Pretty simple to do. Ordered the sensor on ebay for about $30.
    It is located inside the passenger side mirror unbelievably. Just pop the mirror glass out and the cover off and you'll have easy access.
    You'll need a soldering iron and some small heat shrink. Takes about 15 mins. to do.

    2013 500 Sport - Espresso Brown
    2017 500c Abarth Cabrio - Rosso Red
    Abarth mods:
    Aodhan AH-02 17x8 Wheels
    4 Point Roll Bar
    Madness CF Front Lip
    Madness CF Rear Lip Extension
    EC Phase 2 with P&B's Tune
    Tsudo Hi-flow Cat & Cat Back Exhaust
    Lots of CF trim
    Forge Blow Off
    Forge WGA
    Tork Intake & OG Racing Ram Air Pipe.
    Madness Bronze & CF Front Brace
    Speedlab 25mm Front Sway Bar
    CFP 25mm Rear Torsion Bar
    Chassis Braces
    BC Racing Coilovers
    Custom Tan Leather Interior
    more....

  10. #7
    Member
    Join Date
    Jan 2021
    Location
    Alabama Gulf Coast
    Posts
    39
    Thanks
    1
    Thanked 33 Times in 16 Posts
    Quote Originally Posted by map View Post
    I like your idea of replacing the thermistor. If you can locate one, try to find a +/- 1% model. I understand it's using the internal (mounted in the dash) and external temps to determine when to turn on/off the A/C; not sure if it affects when to open the heat flap. When the unit goes bad it usually reads higher than normal temps, but a couple 500e owners had them read low temps... and the reported A/C wouldn't come on. (That makes sense... why run A/C if it's 30 degrees outside.) It is also responsible for turning on the ice warning light.

    Several cars I've tinkered with had temp sensors low and near the grill. That area could become heat soaked on the 500... the mirror would be a more sensible location. I don't know if there's a second temp sensor near the throttle body intake. That would make sense to me but Fiat sometimes does things differently.
    I understand it's a 10k ohm thermistor. I ordered a couple which are supposed to be +- 1%. If the resistance is low, the temperature would read high so I'm, guessing mine has an open because it constantly shows 104 degrees. Those with an abnormally low reading probably have a short and, now that I think about it, it makes sense that a very low reading might disable the A/C compressor.

    Anyhow, I'll open the mirror and solder in a new thermistor shortly which, fingers crossed, will give a correct instrument panel reading and prevent those check engine lights which, to me anyway, are worrisome since it COULD mean something serious.

  11. #8
    Senior Member mp4guy's Avatar
    Join Date
    Jun 2014
    Location
    New York
    Posts
    627
    Thanks
    190
    Thanked 320 Times in 199 Posts
    Quick! Somebody alert Autoblog!
    Phase 0, Neu-F Torque Bushing, Neu-F 28mm rear bar, Front & Rear Koni Yellows, 4C coils, Craven Short Shifter, GFB-DV, El Gato Braces, Corsa Forza center brace

    Abarth & Co. Corse Marche 38/72 Torino Tel. 794.894

  12. #9
    Moderator map's Avatar
    Join Date
    Dec 2018
    Location
    Eugene
    Posts
    2,195
    Thanks
    654
    Thanked 690 Times in 571 Posts
    Quote Originally Posted by Mozella View Post
    I understand it's a 10k ohm thermistor. I ordered a couple which are supposed to be +- 1%.
    There's a successful replacement post here: http://www.fiat500usaforum.com/showt...erature-sensor


    Last edited by map; 04-12-2021 at 04:54 PM.

  13. #10
    Member
    Join Date
    Jan 2021
    Location
    Alabama Gulf Coast
    Posts
    39
    Thanks
    1
    Thanked 33 Times in 16 Posts
    UPDATE: The 10k ohm thermistors arrived from Amazon yesterday. I tilted the mirror full down, popped off the plastic access cover, disconnected the mirror power connector by pressing the tab, unbolted the mirror, and took it to my bench.
    Then I pried off the glass and rotated the sensor holder so I could lift it out of the bottom of the mirror housing. Then I cut the old thermistor off as close to the sensor as possible so the remaining wires were as long as possible. Then, using a Dremel tool, I ground away the potting and removed the remains of the old sensor. I put on my magnifying headset and heated up my smallest soldering iron. I soldered in the new thermistor using my best neurosurgeon techniques. The wires are very small and the working space is limited, particularly the length of the old wires. Don't forget to use heat shrink tubing and when you heat it with a heat gun do not overheat any of the components of the adjustable mirror mechanism.
    I potted the new thermistor with some 5 minute epoxy and as soon as it was cured, I reinstalled the sensor holder, popped the glass back in place, and remounted the mirror on the car.
    To my delight, the dash reading was now reading ambient temperature of 67 degrees rather than 104 to 106 degrees. Problem solved for less than ten bucks. Total time about 40 minutes start to finish.

Page 1 of 2 1 2 LastLast

Similar Threads

  1. Ambient air temperature sensor
    By Romanoaf in forum Fiat 500 DIY
    Replies: 5
    Last Post: 02-07-2020, 02:14 AM
  2. P0073 - ambient temperature sensor high - location?
    By PLP in forum Fiat 500X Issues and Concerns
    Replies: 8
    Last Post: 12-19-2017, 10:31 AM
  3. Ambient temperature reading wrong
    By SoggyWenis in forum Fiat 500 ABARTH Issues and Concerns
    Replies: 3
    Last Post: 12-28-2016, 03:10 PM
  4. Air Intake Temperature Sensor
    By lower byhalia in forum Fiat 500 DIY
    Replies: 0
    Last Post: 06-07-2014, 08:37 AM

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •