ECC Error code 4-1-8 No Control Signal To ECC Power Stage

CRM · Post by **CRM** » Sun Jan 03, 2021 10:12 am

Hi, hopefully somebody can help.
I recently had a problem with my 850R where the heater fan stopped blowing so I replaced the fuses in slot 5 & 31. Obviously this was a bad move as it nearly started a fire as the fan had seized and the replaced fuse caused it to go in to melt down as smoke came out of all the vents. It took a while but I managed to get a second hand replacement fan (right hand drive vehicle). After swapping out the fan I reconnected the power and the fan came on full blast with no key in the ignition!! After reading up a lot of threads it sounded like I may have fried the power stage resistor. Getting a replacement power stage (part no. 9134933) is harder than flying to the moon! Eventually, I managed to get a second hand one which I was told worked. I have now replaced my power stage with the one I managed to find but the fan still comes on regardless of the ignition being off. I have also noticed that the fan speed slider on the ECC has no effect but it does is make the blue relay (part 9130270) located next to the power stage click. I have ordered one of these relays off eBay to see if it makes any difference. I can get the fan to stop if I pull the plug with the blue wire out of the power stage - I presume that is taking the ground away.

I decided to see what codes were stored and got 124, 411, 414 and 418. I then tried clearing the codes and am now left with 124 and 418 (411 & 414 were old codes for the seized fan, presumably?). Now I am at a loss as to what to do. Hopefully the relay when it comes will sort the problem but I don't feel confident. I suppose the second hand power stage I bought could also be bad but the person selling seemed confident it tested fine. As these power stages are rarer than hens teeth there may be no way of getting this fixed - perhaps hard wire a switch and just have it blowing full blast all the time but not ideal. It could even push me to sell the car which I don't want to do but can't drive safely with windows fogging up all the time. HELP!

misha · Post by **misha** » Sun Jan 03, 2021 3:55 pm

Check if you didn't crossed main connectors(2 pin black one) for blower's main power.
It happened to me when i was replacing mine.

No control signal to power stage could be bad ECC.
They are prone to failure.

YouTube · Post by **wizechatmgr** » Wed Jan 06, 2021 8:29 am

The good part is the ECC's can usually be found on ebay for $40-80 =)

misha · Post by **misha** » Wed Jan 06, 2021 9:08 am

Yes...but there are at least 3 different versions which are NOT interchangeable.

Cookeh · Post by **Cookeh** » Wed Jan 06, 2021 10:50 am

wizechatmgr wrote: ↑Wed Jan 06, 2021 8:29 am The good part is the ECC's can usually be found on ebay for $40-80 =)

In the UK ECC is incredibly rare, it was an option on top spec CD models - and not a popular option at all. I've only ever seen one breaker car with ECC in 3 years and they are non-existent on UK sites. Of course they can be shipped from the US, but thats a huge gamble given the lack of cross-compatibility between versions.

CRM · Post by **CRM** » Sat Jan 09, 2021 10:04 am

misha wrote: ↑Sun Jan 03, 2021 3:55 pm Check if you didn't crossed main connectors(2 pin black one) for blower's main power.
It happened to me when i was replacing mine.

No control signal to power stage could be bad ECC.
They are prone to failure.

I wish it was that. When you say crossed due you mean using the wrong plug. The connector I have going to the blower has a black and a blue wire: is that correct?

CRM · Post by **CRM** » Sat Jan 09, 2021 10:13 am

misha wrote: ↑Wed Jan 06, 2021 9:08 am Yes...but there are at least 3 different versions which are NOT interchangeable.

The power stage model I need is 9134933 which is near on impossible to find for sale. It would be good if someone could test the ones I have or recondition. There are some with a model number 9134932 which is for left hand drive (mine is right hand) is this the same apart from the connectors being on the opposite side. Would one of these work ? not sure if there would be room as connectors are on opposite side and fan housing may get in the way, perhaps could make a bracket to bring it back a bit providing glove box can still get back in.

misha · Post by **misha** » Sat Jan 09, 2021 10:33 am

I can't clearly remember now....but the connector i plugged in fitted perfectly and blower started in high speed with key removed from ignition...it was a "live" plug.

I knew immediately that i plugged wrong one...rechecked...and second time i plugged the correct one.Turned key in pos.I and everything worked perfectly.

It was more than a year ago and that wasn't the first time i worked on the heater blower on these cars... I just was in a hurry and made a mistake for the 1st time.

CRM · Post by **CRM** » Sat Jan 09, 2021 10:41 am

misha wrote: ↑Sat Jan 09, 2021 10:33 am I can't clearly remember now....but the connector i plugged in fitted perfectly and blower started in high speed with key removed from ignition...it was a "live" plug.

I knew immediately that i plugged wrong one...rechecked...and second time i plugged the correct one.Turned key in pos.I and everything worked perfectly.

It was more than a year ago and that wasn't the first time i worked on the heater blower on these cars... I just was in a hurry and made a mistake for the 1st time.

Thank you for replying so quick. I have found another post where someone fixed the same issue by correcting the mix up of plugs - mine seem to be correct (plug with red and blue wires). So it looks like it's either the power stage or ECC. The ECC's are available second hand but are around £200 so wouldn't want to go to that expense without knowing for sure that mine is broken.

CRM · Post by **CRM** » Sun Jan 17, 2021 1:47 pm

Just sent off my spare power stage 9134933 off for "repair", will report back when it returns!