ambient air sensor, 'E' in display, OBD2, and A/C

[chrisbinsb]

Had an interesting issue the other day. It was very hot (95f and hotter) I noticed the display showed 'E' instead of the external temp.

Then I got a check engine light. I used an OBD2 reader to discover it was caused by a code for the ambient air sensor. I reset it and found a fairly consistent pattern: The temp would show on the gauge correctly when I started the car. A short while later (maybe 3-5 minutes) the AC fan would suddenly start to blow harder and a few seconds later the E would pop up on the display. Later that evening as it cooler, the problem went away and it hasn't returned

Since the E is supposed to be an issue with the A/C system and the OBD2 code is for the outside air temp, what is the relationship between the ambient air sensor and the AC? I would have thought only interior temp really mattered for A/C.

I also used the OBD2 sensor to log readings as I drove and discovered that even when the exterior temp was displayed correctly on the car's display, the log showed it as always 0. Does anyone know if the car simply doesn't report ambient air temp via the OBD2 port? My understanding is that not all cars report all the possible data.

Thanks!

 

[CatmanV2]

Been thinking about this, and the comment on the other place about the ECU may have another sensor.

I'd bet the mirror sensor doesn't output to the OBD port. I'd check but I just don't think I'll have time until next week, if not later.

However, I wonder if there is a fault with the 'other' sensor which is causing the CEL.

C

 

[chrisbinsb]

Been thinking about this, and the comment on the other place about the ECU may have another sensor.

I'd bet the mirror sensor doesn't output to the OBD port. I'd check but I just don't think I'll have time until next week, if not later.

However, I wonder if there is a fault with the 'other' sensor which is causing the CEL.

C

Certainly could be that there is anther sensor that the ECU uses - maybe the mirror sensor is only for the dash temp display? In which case, it would certainly be likely that it doesn't output to the OBD2 port. Regardless, it seems to be a temporary issue, probably heat related as the CEL is off and no sign of the E since that especially hot day

 

[Contigo]

Mine displays E at startup then shows correct outside temp. Apparently the sensor on the dash is suspect but it has no adverse reaction so I am going to leave it

 

[Tompelli]

Had a lot of problems with mine showing the snowflake & 4C in Thailand! This reading would knock the aircon off & leave us having warm air basting us. Had the garage check & clean the external mirror sensor (already replaced 2 years ago) & now performs better but not 100 percent.

Sent from Nokia 920 using Tapatalk

 

[CatmanV2]

Had a lot of problems with mine showing the snowflake & 4C in Thailand! This reading would knock the aircon off & leave us having warm air basting us. Had the garage check & clean the external mirror sensor (already replaced 2 years ago) & now performs better but not 100 percent.

Sent from Nokia 920 using Tapatalk

]

I think there's an issue with the connections through the door, which might be your problem.

C

 

[safrane]

You can get the AC code off the car by pressing the eco and recirculation button together with the ignition kn.

My bet it AA114...sadly I have no idea what the code means.

 

[Contigo]

Yep the codes are spurious and very hard to interpret. sd2/3 is your friend here...

 

[outrun]

Had a similar issue with mine and it was the connection to the sensor in the door which was not well enough connected. The door card had been off to fix the internal handle and the connection was loosened somehow during that process. I'd suspect that the extreme heat is affecting that connector in your case. Perhaps getting to the connection in the door and insulating it would help?

 

[Fran]

Mine displays E at startup too. My indie, Giallo, told me was a problem with the sensor, so I bought and installed a new one. Still showing E which I believe is just the initial check up when starting. I have no other problems and it show the external temperature correctly.

F

 

[CatmanV2]

No it shouldn't do that. If you get the error code, it might explain it. Mine does an E in cold weather, which is the mixer flaps sticking as whatever lube they use thickens up.

C

 

[Contigo]

Yep same as mine Fran

 

[BennyD]

I had the 'E' a while ago. It turned out to be one of the little servo motors which control either the hot/cold air or the air distribution had gone 'phut'. What a pig of a job. All the dash has to come out to get to the motors which are situated behind the shaped metal air-con pipes. It's as though they started with these two little motors and built the bl00dy car around them. It has worked perfectly since we did it, which is nice as it was pumping out hot air even when the outside air temp was 34 degrees!

 

[chrisbinsb]

This mysterious E is very interesting. Mine came on again yesterday for no obvious reason....

 

[davy83]

Nice thread. My car has occasionally thrown up an "E" too. It has never persisted and after a restart never come back. I am not at home but i wonder if my workshop manual has the AC error codes in it? I will have a look when i get back next week. I would add (yes i had some thing worth saying) that the description of how the AC works in the manual which is quite lengthy, describes how the AC adapts to the outside weather including the sensor under the windscreen which tells it if there is sunlight coming in, so i suspect the AC does take account of the exterior temperature as well as the interior temperature. So a flaky mirror sensor might well make the AC unit throw up an E.

 

[Contigo]

There is indeed a list of all the sensor Error codes and mine came up with the Ambient Sensor. My air con doesn't work, hasn't done since I got it but as we are in the first summer I guess I can try regassing and hoping that the condensor and drier are not shot but when I changed the Rad last week the condensor looked like it had seen better days. Looks like it was made out of cardboard tbh.

 

[Contigo]

Here's the info and if it shows the E then the outside temp then there is a problem. Mine gives error code related to Ambient Sensor on the dash.

 

[safrane]

So what is AA114? PLEASE

 

[Contigo]

Think Catman said Recirc flaps.

 

[safrane]

Thank you....good job I don't use that function then.