Air Conditioning problems

[Spinout93]

Hey guys - My 93' a/c is acting weird. If I set the temp. controller inside to maintain 72 degrees the compressor will cycle on and off as if it is low of ref. but when I touch the accumalator and the return line they are extremely cold.
I put a digital therm. in the air vents and while it is running it will produce 48 deg. air. After the compressor cycles a few times the green light starts to blink at the controls. I do not have any codes to read. Any suggestions?
Thanks again.

 

[whsteele@bellsouth.net]

AC problems

You might want to also check your temp sensors, one for outside temp is at bottom right of radiator below bumper, one is on passenger side in air vent and the sun temp sensor is at top of dash up near windshield. All this effect the cycle and how the system responds to amount of temp drop needed.

Let me know how it goes.

Wayne

 

[KOPBET]

If the LEDs are blinking then shouldn't you have a DTC code set?

Press and hold the fan "UP" and "DOWN" arrows at the same time for ~5 seconds. The LCD will read "-00". Then push the "AUTO FAN" and the LCD will show stored DTCs. If the inside or outside air temp sensor or sun load temp sensor is open or shorted a code will be present.

You can then press the fan up or down button to select a system parameter number then press the "AUTO" button to display its corresponding value.

Inside air temp sensor is parameter "2". Range 10-130.
Outside air temp sensor is parameter "3". Range 10-130.
Sun load is parameter "4". Range 0-120.
Temperature setting is parameter "1". Range 60°-90°

 

[whsteele@bellsouth.net]

AC problems DTC codes

I followed the procedure you outlined and found the following: code 02=136, code 03=98, code 04=140 and code 01=64. The first code that displayed after the 00 was code 07 and that equaled 00. I also did all the codes in the system using the up and down fan and checking each parameter. Not sure what all this is telling me. Is the code 07 the problem?

 

[KOPBET]

I didn't mention that the parameter categories will have a negative sign next to them as in "-00". Parameter "-00" is "system faults" so if a "07" appears there after pushing the "AUTO FAN" button then yes, you have a "07" fault which means the sun load sensor is faulty.

If you select the "-04" parameter and examine its value while varying the light input to the sun load sensor then you can check it. In other words if the car is outside with a lot of light then cover the sensor. If the car is in the garage with little light then shine a bright light on it. The parameter value should vary correspondingly.

Inside air temp sensor is parameter "-02". Yours is "136" which is a little outside the specified range but likely it is Ok.

Outside air temp sensor is parameter "-03". Yours is "98" which is Ok.

Sun load is parameter "-04". Yours is "140". Way high.

 

[KOPBET]

Where'd everybody run off to?

 

[Bonnell]

Hi Kopbet,

Do you know if this applies to the '88 model?

Thanks,

J

 

[Spinout93]

I finally got a chance to run the codes on my DTC's. They are as follows...00=9,01=86,02=104,03=165,04=199. I did apply a flashlight to # 4 and the value started to fall. It appears that I may have several sensor problems accordingly to your range sheet. Can this be possible or should I look further? Can they be calibrated or are they factory set? I also retrieved the remaning values and I would like to know if they are in the OK range. Can you direct me to the web site that has these parameters? Thanks a million.

 

[KOPBET]

Hi Kopbet,

Do you know if this applies to the '88 model?

Thanks,

J

Hello Bonnell,

"Knowledge is Power" indeed. But in this case I have none. Sorry. Electronic air was an option in coupes staring in '86 I believe, but I don't know if the operation and diags were similar or not.

Perhaps Ken or someone else with that vintage car will jump in here and answer for you.

edit: after more checking it appears this functionality began in '90.

 

[KOPBET]

I finally got a chance to run the codes on my DTC's. They are as follows...00=9,01=86,02=104,03=165,04=199. I did apply a flashlight to # 4 and the value started to fall. It appears that I may have several sensor problems accordingly to your range sheet. Can this be possible or should I look further? Can they be calibrated or are they factory set? I also retrieved the remaning values and I would like to know if they are in the OK range. Can you direct me to the web site that has these parameters? Thanks a million.

Sure!

http://www.idavette.net/tech/c4diag.htm

According to the DTCs, it thinks you are low on freon which may account for the cycling of the compressor. Have you had an A/C man check the system? I suspect the sensor ranges are fixed and non-adjustable.

I'll double check those ranges against yours, but I agree with you that two of them are very high.

What is the temp where you are anyway? Time for A/C already?

 

[KOPBET]

Let me see if I can get this right.

The range of the parameters is

minus sign added to the left of the value increases it by 100

02 - In car temp sensor is 10 (hot to -(minus)130 (cold) (which is really 230).

03 - Outside temp sensor is 10 (hot) to -(minus)130 (cold)

04 - Sun load sensor is 0 (max light) to -(minus)120 (dark) (which is really 220).

So, your values as indicated should be ok, AS LONG AS you don't have a negative sign displayed next to the values.

Your values were:
02-104
03-165
04-199

I checked my car while it was sitting cool in the garage:
02-150
03-105
04-198

 

[Spinout93]

Thanks for the codes and analyzing my parameters for me. In question to the a/c charge I would think 48 degree air for r-12 would be enough to atleast keep it running, but with the factor of the three temp probes and it was only 70 - 71 degrees outside makes me think this car is smarter than I thought it was. God I love corvettes... I will have to buy a charge kit with a guage set, then I will have to chase down the possible leak. Any luck with those over the counter a/c leak repair kits?

 

[KOPBET]

Thanks for the codes and analyzing my parameters for me. In question to the a/c charge I would think 48 degree air for r-12 would be enough to atleast keep it running, but with the factor of the three temp probes and it was only 70 - 71 degrees outside makes me think this car is smarter than I thought it was. God I love corvettes... I will have to buy a charge kit with a guage set, then I will have to chase down the possible leak. Any luck with those over the counter a/c leak repair kits?

I don't do AC, and whenever I've had a leak I've always had to have the hose, seal or whatever replaced professionally. 48° air when it's 70° outside doesn't necessarily mean much to me. If it was 108° outside then 48° would sound pretty good.