ECC doesn't work on AUT when engine is started - Volvo 850

Citrofan · Post by **Citrofan** » 12 Feb 2007, 02:17

Hello
I'm come from Poland, sorry for my English. I found Your posts on forum. I have problem with my ECC. First of all when i buy my volvo 850 one month ago there was a problem ECC dosetn work in AUT position at all and the blower fan shut off when i drive, sometimes after 1 minut sometimes after 15 and ten fan will squize too. I replaced the ECC unit and the blower fan buy used from another volvo 850. Now it's seems to be ok the blower run quiet everything worsk but... when the kay is in the I or II position and the fan operating in AUT position everything work fine the blower fan is run and when i move the temperatur knob to max haeting or max coling position the fan is run at highest speed when i set for ex. 19 degrees celsius it speen slowly. The problem is when i move the key to the III position and start the engine! the fan is shut off wen te fan cotrol is in AUT position and it doesnt work at all! When i move it manually to some position it work! It work on any position but wotn works at AUT onyly when engine is started! what it happend? Can you help me?
the REC an AC coded blink a read the error code and it is 1-3-5 a deleted tihis error an was driving a few day and the REC and AC led don't blink anymore but today will blinks again, tomorrow i read the error i think it wil be 1-3-5 again and it is mean that "Engine temperature no frequency signal" it my be the problem? and the ECC dodn't work in AUT position whe engine is running?? Please help me! Thanks an sorry for my bad English again, I hope that You understend what i have been written.
I have one AC relay not two, and probably the relay is ok, because when engine is not runnig everything its working fine on AUT postions.

Post by **Ozark Lee** » 12 Feb 2007, 07:49

Your climate control unit is not receiving a signal from the engine temperature sensor. It is designed to not turn on the fan until the coolant is warm enough to provide heat.

Does your temperature gauge on the instrument cluster work properly? It should rise to the middle position of its range within the first kilometer or so of driving and stay there. If your gauge is not working properly I would replace the engine coolant temperature sensor.

If your temperature gauge is working properly there is a problem in the wiring between the instrument cluster and the ECC unit. The coolant temperature is sent from the instrument cluster to the climate control on a Green wire with a gray stripe and it goes to pin 23 on the A connector in the back of the climate control unit. The A connector is the widest connector of the 3 connectors that plug into the unit. If you have a voltmeter available you should be able to measure a voltage of around 5 volts DC on that wire.

Good Luck,

...Lee

Citrofan · Post by **Citrofan** » 12 Feb 2007, 08:57

Hello again.
Yes, temperature gauge is working properly, it rise to the middle position and stay there. Today I chek connection on the wire you told me. But one think still confused me, i think that this signal isn't the problem. Toy say that It is designed to not turn on the fan until the coolant is warm enough to provide heat, but if i move the temperature knob to max cooling, the blower fun shuld start provide teh cool air direct from outdoor am i right? So why it doesn't work even that at all? Why it works great when engine stopped? there is no signal form engine collant too when is stoped and ECC work great. What it's happend?

Citrofan · Post by **Citrofan** » 12 Feb 2007, 10:38

Hello again
I just come back from my car. I check the pin 23 (green/gray) on ECC unit and there is 5V when engine is started there is 6V. i reset the 135 error code an try tu start and stop the blower fan, try to start engine and stop an after few times the REC and AC start blinking again, i read the code an again is 1-3-5.

what is goin on? How can I repear it? It is possible thah te blower fan or ECC unit that i buy from other used volvo is still bad and i need another?

Post by **Ozark Lee** » 12 Feb 2007, 12:58

I spent some time going through all of my available manuals and, unfortunately, the manuals don't say anything about what should occur with the key in position II but the car not running.

I actually have the manual climate control unit so I don't have a way to test the system hands on.

From the service manual I have a paragraph on what is normal fan operation.

As vehicle speed increases, the fan speed will be reduced to maintain constant airflow throughout the passenger compartment. When heating the passenger compartment after starting a cold engine, the fan speed is gradually increased as the engine coolant temperature rises.

Since the ECC is not correctly interpreting the engine coolant temperature sensor signal I don't think the ECC ever figures out that the engine is warm and the fan never speeds up.

The question now becomes why. Since you have voltage on the Green/Gray wire we must assume that the signal is being sent from the instrument cluster to the ECC unit but, for whatever reason, the ECC is not recognizing the signal which is why you get the 1-3-5 code.

Only 2 things come to mind.

One would be that there is a dirty connection between the A connector and the ECC unit. If you have access to contact cleaner it would be worth a try to spray both the male and female sides of the A connector with the cleaner. If you don't have contact cleaner alcohol will sometimes work.

The other possibility is, as you suggested, that the ECC unit itself is faulty.

Hopefully it is just a dirty connection. Let us know.

...Lee

Citrofan · Post by **Citrofan** » 15 Feb 2007, 13:30

hello again!
Today I buy and install anotehr ECC unit and... nothing change! The blower fan still isn't running on AUT setting when the engine is running!
I still get a 1-3-5 error code on ECC but is another ECC. People please help me! I also read the codes form the instrument panel and there is a 1-2-2 code what means "Temperature signal interval too long". The engine temperature meter on dashboard worsk fine but maybe something is wrogn whit this coolant temerature signal and because that my ECC won't work on AUT when the engine is on. Any ideas??

Post by **Ozark Lee** » 16 Feb 2007, 07:40

Both of the codes are related to the same thing, the coolant temperature sensor. It is perplexing that the temperature gauge works fine.

The test procedures to troubleshoot the instrument panel error code are quite involved but they are outlined in the service manual here.

https://www.matthewsvolvosite.com/chat/p ... php?t=8018

Once you download and unzip the manual, find the files called:

ac heater system auto.pdf

and

instrument panel.pdf

The troubleshooting procedures for both errors are outlined in great detail.

Hopefully someone else will chime in here on what an ECC normally does when the key is turned to position II but the car not started. My climate control is the manual version so I'm not sure what normal operation is.

...Lee

Citrofan · Post by **Citrofan** » 16 Feb 2007, 11:48

I alI already have been tested the instrument panel it works fine but there was one error 1-2-2 Coolant engine temperatur signal intervals too long, whatever that means. But one thing is shure! the temperature sensor is working good because signal from them goes to the main ECU and then to jetronic unit. From jestronic the signal is going to te instrument panel and maybe the problem is on that way!! but the temperature on the instrument panel is shown correctly!
There is no error in ECU an jetronic units. What is going on. I don't belive that ECC dont work on start engine because of bad coolant temp. signal! Maybe there is another porblem???
I forgot to say but i also don't have the gas in airconditioning system, now is winter and I don;t need to refill this system maybe on summer, but it may cause my problem??

VolvogoBrrrrt · Post by **VolvogoBrrrrt** » 13 Apr 2022, 21:35

Working link for the manual zip file referred to above:
https://web.archive.org/web/20070304160 ... vo_850.zip