Exploring the Volvo ECC.
ECC is a further development of the ACC system. ECC was introduced on the 940/960 from the beginning of 1991. As before, the unit is of the air–mixing type, which means that cold and heated air are mixed to achieve the desired temperature. The advantage of this is that the interior temperature can be varied rapidly. The system features a new, microprocessor–based control system.
MVS Forum Member steve asks:
First a brief history: The fault lights began blinking several years ago. I did not retrive the codes. About 6 months ago the blower fan stopped working after about a year of the blower making whining noises. I replaced the blower motor and resistor module. I reset the codes by disconnecting the battery while doing the R&R. Afterwards the fan worked great and still does.
Now the dreded lights have begun blinking again. I perceive no problem with the blower. I do notice however that the ECC has not been able to keep the temperature controlled the way it should, like it did when new. For example when new, if you set the temp at 72 deg. that is exactly where it was maintained. Now, it might give you 72 for a while but will periodically freeze or bake you depending on which way the wind was blowing that day. I figure a stuck or malfunctioning blend door.
Anyhow, today I read the codes: 211, 321, 322,325,414,417,418.
I need to identify these codes and get guidance to remedy them.
Thanks in advance.
MVS Forum Member TEAGLESON adds:
I also have aproblem with the heater blower in my 1993 850 with ECC.
Does anybody know how to test the heater resistor pack that controls the blower fan??
I posted a separate question earlier today.
MVS Forum Member eric relied:
I just discovered this web site. Have ’93 850 GLT(165K and original to family) with ECC faults and am in process of trying to get blower to work. Have volvo factory book as well as Haynes. Replaced motor from FCP Groton. (Live 40 miles from them. Go right to store. Great folks.) No luck. Have metered a short in power stage. Joined VCOA for 15% discount at dealer. Have found short in both temp sensor/motors and removing these required lowering roof lining to get at screws. Both motors turn freely. Have faults on all damper motors too. According to wiring diagram the ground is common to them. Am trying to replace anything that the meter says is bad(have had faults for a while and they just sort of accumulated without my knowing it until REC/ACC lights just recently flashed. Admit I am somewhat wandering around and it is uncomfortable. Don’t want to get new ECC if I have fault codes elsewhere that may cure problem. Am ordering new power stage from FCP($99). Discount price at dealer still higher. It is my wife’s car. I have been her resident mechanic for 30+ years and gently told her no more fancy shmancy automatic stuff. My Ram 1500 pickup is stripped and a joy to maintain. Have a web site to share that may work for some repairs. It is BBA Remanufacturing. They could not fix my ABS module but it was not for not trying. Nice folks.