98 V70 ECC Drvr HOT Pass COLD Issue Topic is solved

[dosbricks]

Anyone have to replace their ECC unit? Where did you get it from? Did it solve your problem?

I bought a used ECC for my '96 850 from Erie VoVo which had been tested and came with 100% guarantee. It fixed the problem for about $75. This was about four years ago.

I bought a used (no guarantee) one for the S70 for $18 from an ebay JY seller and it was worse than the original. The weird part is that when I swapped the original back in a few weeks ago, it has functioned perfectly ever since.

If there are further problems, the pick-n-pull would be my first choice just to see if I could get lucky.

[scot850]

I have bought one on ebay and pulled a couple from PnP for about $20-30 CDN. I bought them to try to fix an annoying clicking noise from the center of the car, but eventually found a faulty servo motor. Swapped it an all was well.

PnP is worth a try. They are easy to pull (wear gloves as there is a sharp metal edge under there). Once you have pulled the radio out, put a hand in under the unit towards the back of the unit and give a sharp heave up at the back. That should release it. They can sometimes be stubborn, so that is where the gloves also come in to protect you hands.

If you are in Texas (I know it is a big state) it may be worth contact rpsi (Robert that does all the youtube how to videos) as he may have a good working spare you can try.

Neil.

[sleddriver]

Found a used one locally for $100. Not sure if it's guaranteed or not. They might let me try it out first...maybe. I need to check other yards as well. Found lots on ebay for $40, but who know's if they're good or not? Erie Volvo wants $100 as well. They might actually guarantee it though. Never done business with them.

I checked the ESR of all of the elec. caps, and initially meas. one that appeared to be way off. I'll have to check a datasheet for a more accurate value. The good thing about the ESR meter is it'll test in-ckt and accurately measures very, very low resistances. It also does so at a low enough voltage to not turn on any PN junctions. The toughest part will be removing the tiny SMECs without damaging them.

One point about this ckt in the ECC is that there are three others just like it: Same PCB parts. So I have three more to compare it to. Further, to read this 0 - 5V position feedback signal, I'm assuming an A/D converter is used. Could be one channel out of four is wobbly, and thus unable to read the signal. Also could be that the 5V source is being pulled down for some reason (bad elec. cap, weak regulator, shorted transistor or diode) so a full 5V's isn't getting to all four pots. It also has to switch +- 12V to turn the motors, sometimes more than one at a time.

[sleddriver]

Major Update:

Some very interesting things happened today. I used the Multi-Tester Pro to "adjust motors" while meas. voltages. Verified +5V on ECC pin A7, which is applied to the top of each damper motors pot. Meas. a constant 0.9V on pin A12, meaning the motor shaft never moved. So I checked the V between pins A8 & A9 (drvrs temp motor terminals). It started at 0.5V, then after a brief delay rose to 11V, then back down to 0.5V for the rest of the "adjust motors" cycle. When I checked pins A10 & A11 (pass temp motor), the V started at 0, then rose to +11, then dropped to -11V, then returned to 0. Makes sense as it moved the motor one direction, then another to monitor the signal from the position pot.

About that time my indy walked over with an ECC from the shop car, so we plugged it in. After starting, I now had all controls working! Temp on both sides, air control, recirc and A/C. So I figured I had finally answered this riddle: My Ecc is faulty, not the drvr temp damper motor. Ran the "adjust motors" routine in the MTP and it failed the shop ECC !!! Go figure. We never could get it to pass!

So we put the shop ECC back into the shop car and it was still messed up. Cleared codes and it set a few more, that obviously didn't belong to the shop car. Finally got them cleared, but now the shop cars climate control is all messed up and the green A/C LED blinks on it too! We looked at each other in disbelief....WTH?

Plugged my ECC back into my car and now drvr & pass temp are set to cold and air control is set to defrost vents.

So the MTP "adjust motors" did something to MY ECC when I first used it two months (?) ago and I've been fighting it ever since! And now that adjustment routine has screwed up the shops ECC as well!

Anyone else successfully calibrated their damper motors with this routine on a MTP?

[sleddriver]

Update:

I complete the V meas. I started above on the remaining damper motors. The drvrs damper motor is the only one that doesn't reverse direction. This isn't the motors fault though, it's the ECC. Specifically, whatever motor driver Alps used connected to pins A8 & 9. Could be as simple as a single transistor.

As the ambient temp here has been in the low-70's, 100% HOT isn't appropriate. So I pulled the motor connectors off both the drvr & pass side, and closed the heater flap on both sides using a 9V battery and left the motor connectors unplugged. A/C works fine and no more HOT air blowing in my face. This will work until I either fix my ECC or replace it.

What a long, strange, frustrating trip this problems been.......

[sleddriver]

Update:

Arranged to borrow a known, good ECC. Upon installation, everything worked as it should! So, this confirmed my earlier voltage tests.

It's interesting to note that the ECC blamed the drvr temp motor as faulty, but this wasn't true. The ECC itself was faulty. Obviously, it's self-test routine doesn't account for a fault in the motor drive ckt. Further, paying $150 for a new motor would have been a waste as electrical parts usually are not returnable.

Therefore, if you ever experience a ECC-422 fault code or another one related to the motor, its operation or the position sensor. It may be the motor, but then again, it may NOT. Pull the motor and check it with an ohmmeter. If it passes, then suspect the ECC despite the code you pulled.

[sleddriver]

UPDATE:

Found a nice looking ECC console at a local PNP + a replacement cabin temp sensor. Cleaned and installed today and IT WORKS!! SOLVED! No more orange LED's flashing at me.

During the interim, I moved the drvr HOT damper to COLD and the RECIRC damper to ON, using a 9V battery connected to the motor leads. The air control was fixed to the dash vents. This gave me COLD A/C during the heat, while I fixed other issues on the car. The yard charged just $15 for the ECC, while another wanted $60, another $80 and another $100! Got lucky I suppose.

Why so long? Hadn't bothered to scout local yards in more than a few decades. What broke on the car during that time needed a new part. Also, I was busy taking care of other needs. The past seven months, I've spent FAR more hours on the sled than every before in its 18yrs. I now understand why most simply ditch older Volvos. My 14yr old SAAB 900T was far less work, even with 256,000mi on her. MUCH simplier car. I miss those days....

Lots of EXPENSE to pay someone else to do it; Lots of TIME to DIY!

Old Volvos Never Die: They Just Drive Their Owners Nuts...and Broke!

[sleddriver]

Didn't realize until too late, that I can update my title to SOLVED!

[scot850]

Nice to get one issue solved! Junk yards will become your friends. My local PnP and I are almost on first name terms now. That is always a bad sign!

Neil.

[sleddriver]

Indeed it is!

The car that keeps on taking: TIME, $$$, time, time, time, time........................
DIY has saved me thousands upon thousands though, particularly in the last seven months. I'll have to post all the work I've done in a new post. No doubt many hear could identify with my list, including yourself. I just didn't plan on having all of these issues arise AT ONCE!

Now I have yet another one: Front engine oil leak. Wasn't there three weeks ago. Both oil cooler lines have already been replaced once. Crank seal was also replaced with OEM about 10yrs ago. It wasn't leaking then, but done as it was a TB service. Might be oil filter too. It's between the crank & filter.

And.....AND....my old yrs-long-nemesis has returned: P0455 GROSS Evap Leak!! Eeeeek! Thought I'd FINALLY slayed that dragon for good! First clue is a torn seal on the OEM Volvo gas-cap I bought just last Fall. Not even a year old! WUWT? Shocked it's already torn!

Re: Junk Yard. Too bad there's a collasial $%^#@! at the one I've been to who is one twisted #$%&*(@. I have to interact with this @$$^&*_ twice when I go. Worse, it has the best collection of junkers. Rotten luck that.....

Calgary SURE is a LOT cooler than here this time of year. Just beautiful up there......