boehnc

Maybe a simple answer to this newbie question.

I'm getting no heat from my vents until I turn the temp to max 85 degrees. I've researched and performed the self diagnosis. I understand I'm supposed to get three readings for test mode 51.

It's 100 degrees out today. The first code read 117, second code read 120 and I didn't even get a third reading when I pressed the Defrost button..it took me back to 51.

Anything abnormal about the temp readings or the missing third reading?

DennisMik

iTrader: (2)

When you set the temperature to 85, that is actually the "heat always on" position. Similarly, when using the air conditioner, setting the temperature to 65 is actually the "a/c always on" position.

You should get 3 readings from test 51. They are, in order of display: ambient (outside) temperature, in-vehicle (cabin) temperature and intake (cabin sampling) sensor. Since you don't get a reading from the intake sensor, that seems to be your problem. To start, I would check to see if it is connected. It is behind the little "grill" in the heater control panel.

As for the test going back and repeating test 51 when you press the DEF button, that is exactly what it is supposed to do. If you want to advance to step 52, press the REC (Recirculate) button.

boehnc

Great..thanks for the response Dennis. I assumed even if the intake sensor was faulty it would still give me some kind of reading..albeit faulty. Thanks for the info...Since it was 100 degrees outside, and the ambient temp reading was way off at 117..and no third reading, could this be symptoms of something bigger with the unit?

Trini Boom

iTrader: (5)

So let me get this straight, if I do not see the third reading ad it goes back to 51, then that sensor is bad? Wouldn't it have thrown a malfunction code from the 20 test?

njmaxseltd

iTrader: (19)

Is there something wrong with the system or are you just looking for codes?

At 100 degrees outside one wouldn't expect any "heat" from automatic climate control until you brought the interior of the car down into the 70's and removed the sun load.

So what's the system doing that has you looking for an error?

DennisMik

iTrader: (2)

The diagnostic goes through each category, checking whatever and reports it. you then have to tell the diagnostic to either repeat the category or move on to the next one.

The self test does not automatically loop on a bad reading. You as the person running the diagnostic have to tell it to. And that is what the op was doing.

I agree that the op should have had an error 24 during the 20 testing, maybe he did and didn't tell us.

boehnc

My car overheated a bit last weekend going up into the mountains. Been doing this last couple years, thankfully I dont go uphill much. But tried to take heat away from the engine, so I increased the temp...noticed cold air until I reached 85..which is a new thing. So, trying to fix the overheating issue..found another I need to work on...

My codes were:

1. 25 (didn't have car in sunlight)
2. 30
3. 41
5. 51
a. 117
b. 120
c. Back to 51

njmaxseltd

iTrader: (19)

What was the outside and interior temp when you tried calling for heat?
Auto climate control will not provide you with heat until you exceed the set point, until them you WILL get cold air.

I'm not 100% sure you chasing a problem just yet.

Example: On a 90 degree day with climate control set to 84 degrees, you'll get ice cold A/C until you drop the cabin temp below 84, then the system will temper the air to maintain set point.

Is that what's happening?

boehnc

Interesting. Maybe. I hardly turn on the AC during the summer. I'll do some tests and report back. Would this affect the 3rd reading on the 51 diagnostic test? And is a 117 ambient temp abnormal if the outdoor temp is actually 100?

njmaxseltd

iTrader: (19)

The temp sensor is just in front of the radiator. If the rad is hot, pavement is hot etc, yes it's possible to see that reading.