ECC can't mantain AUT temp control

AP · Post by AP » 30 Mar 2006, 20:33

I got a 2000 S70 GLT with the Automatic AC or ECC I think it's called. When I start the car the AC conrol panel flashes for 20 sec indicating something is wrong with it. The AC blows cool air but when it's in the "AUT' mode it can't regulate the fan speed or the temp anymore! What has gone wrong and how expensive would it be to repair? I don't trust a VOLVO dealer to troubleshoot and repair it, I'm sure they will overcharge me as usual!

Post by **MadeInJapan** » 30 Mar 2006, 21:41

At least your fan works so this shouldn't be too expensive unless it's the A/C evaporator....God forbid

. The fuse for the ECC is #31 (under the hood- 25amp) check it to make sure it's not blown first. It probably isn't.

I suspect a Rheostat needs to be replaced by your description, but I may be wrong. If it does, it involves replacing a socketed sensor that the blower is plugged into, and requires taking your glove box, knee bloster and airbag cover off to get to, but it's not very expensive and you can do this yourself. Anyway, to make sure (and of course it could be something else entirely) let's do some diagnostics.

Your ECC (Electronic Climate Control) stores diagnostic trouble codes and displays them by the flashing lights that you noticed. To find out what the codes are do this:
Ingition ON, position I or II.
Wait approx. 3 seconds.
Ignition OFF
Ignition ON again.
Wait for .5 seconds (or rather don't wait at all). If a diagnostic trouble code (DTC) is stored, the indicator LED will flash once. Only start pressing the bottons (explained below) after the flashing.
Press in the REC button 2 times within the following 2.5 seconds.

You will get a set of blinking lights in groups of 3 (ie: 2blinks, pause, 3blinks, pause and 1blink....long pause indicating 2-3-1 DTC, etc.) The long pause of 5 second is before the ECC unit give you the next code, if there is more than one problem. You need to write down everyone of these trouble codes. Once you get the same code again, you've gone through all of the trouble codes stored in your system and you can stop.

Now, you want to erase the DTS's (you have to go through all of them for them to be erased, so be patient) Follow the procedure above, but instead of 2 pushes, push the REC button 4 times (very quickly- within 2.5 seconds). Now the codes should be erased, and you would get code 1-1-1 (which means no codes are stored) if you tried the first procedure again .

Now try to use your fan like you normally would. If there's a problem go through the diagnostics above again. Once again, write down your DTC's. The codes that remain after erasing are the ones you need to be concerned about.

Note that the DTC's can also be erased by disconnecting the control module for more than 2 minutes (disconnecting the battery is the easiest way, but make sure you have your radio code if you do this). DTC 5-1-2 (5 blinks, a pause, 1 blink, a pause and then 2 blinks) can only be erased by disconnecting the control module as stated above or by going through a successful self-adjustment or a "set" (explained below).

In the case that you have a new control module, it has to be "set." To do so, you push the REC button 3 times instead of 2 like you did to read the codes, or 4 to erase them. Sometimes a used ECC control module will act like it's never been programmed and will need to be set. That's when you'll get the 5-1-2 DTC.

Hope this all helps. Please post back the DTC's you got AFTER erasing them once. In other words, if you're able to erase the trouble codes, and they don't come back, you've essentially "fixed" the issue(s) you were having with your Electronic Climate Control unit. The number of codes are too extensive to list them all here, so just post yours back here and I'll try to tell you what they mean.

Good luck...and post back if you have trouble with any of the procedure.

AP · Post by AP » 01 Apr 2006, 11:53

Thank you for all the good info there. However when I tried to retrive the DTC's using your techique I got no codes. Everything is fine, no flashing idicators. It's only when you actually start the engine the flashes comes on.
I tried to reset by disconecting the BAT for 2 min, but It's still the same problem when I turn on the engine??? Now I got annother problem on my hands...The Radio code was written as 2933, only there are only buttons for # 1,2,3,4,5,6...No # 9??? I'm calling my dealer on monday!

Post by **pfeener** » 01 Apr 2006, 12:10

Assumming the 2s and 3s are correct, you've only got 8 other possible codes. You get 2 shots and then the radio display will change to off and you'll have to leave the key in position I with the radio on for a couple hours and it will reset and you'll get another 2 shots.

I'm betting on 2633.

Capt Jack · Post by **Capt Jack** » 03 May 2006, 15:51

Try cleaning out the little temperature sensor that's mounted in the dash in the same cluster as the info centre, heated window/mirror and TRACs switch. A Volvo dealer told me that dust inside the little grille causes ECC faults to appear. Regular cleaing with the brush attachment of the vacuum cleaner did the trick!

Post by **JRL** » 03 May 2006, 21:15

It's probably one of the cabin sensors

utvol1984 · Post by **utvol1984** » 05 May 2006, 07:38

My 93 850 has ECC with the little air intake fans behind the grab handles above the front doors. I took them both out and cleaned them - actually replaced one with one I took off an 850 I stripped. Seemed to help for awhile but I kept having similar problems - ECC control unit flashing like a Christmas tree. Local Volvo tech told me I might try switching out the entire control unit in the dash. Since I had the one out of the other (junk) 850 I did that. The "new" unit appeared to be newer than the one I took out - graphics were a bit different. Installed and so far (knock on wood) everything works great. Admittedly I was lucky - I got the ECC unit out of a car I only payed $400 for (blown head gasket). A replacement ECC unit from Volvo runs about $600 I think. If you wind up having to replace the ECC unit, make sure the dealer agrees to take it back if it doesn't solve the problem. Fortunately, replacing the ECC unit is a five minute plug and play operation. Good luck.

BjornT · Post by **BjornT** » 08 May 2006, 13:52

Hi,

I had the same symptom on my -2000 V70 last year.
It turned out to be the actual "ventilation fan" (located behind the glove compartment) that was about to break down.
An error code was read out from the OBD-II connector indicating that the fan engine was "consuming a too high current".
I tried with cleaning the fan and giving it some lubrication but that only helped temporarily ( a month or so.)

So i ended up exchanging the fan.
Volvo wanted some 450$ for only the fan (no work included).
But i managed to find a new fan from a "pirate manufacturer" for about 130$

. The replacement was no problem.
Remove the glove-compartment and behind that you easily see the fan which is held in place with some 4 screws.

Please note: The prices i mention are my re-calculation from Swedish currency. I have no clue about the actual pricing situation for Volvo parts in the US.

Good luck!

Post by **MadeInJapan** » 08 May 2006, 19:39

Believe www.fcpgroton.com also has much cheaper fans. If not there, then you can get one from eeuroparts.com

utvol1984 · Post by **utvol1984** » 19 May 2006, 11:28

Well I have to update my earlier post on this subject. I guess I spoke too soon when I said my ECC problem was "fixed." The ECC module is now acting wierder than Linda Blair's head in "The Excorcist." It can't seem to contol dampers properly, activate the compressor properly and the auto settings don't work at all. So I'm pretty much back to square one. At times the fan spins up hard so I know it can blow hard with the proper signal from the controller - leads me to think the fan motor and resistor are probably okay. I'm tempted to buy a new ECC module (cha ching cha ching $$$) but I'll REALLY be pi$$ed if that doesn't fix it. Guess I'll try to pull codes and see what I come up with.

I have to say that I really like my 850 in all other respects but if I had had any idea what junk this ECC system is, I would have run the other way from this car.