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OK, I'll try to keep my saga brief. I've been searching this and other boards for clues, but have reached the point where I need to ask for insights.
A couple of weeks ago, my 2001 S80 T6 with 204K miles showed a STC message, the temp gauge showed only cold and the car began running very badly. I'll have to take my wife's word for it that all these things came on simultaneously since she was driving. The trip odometer is dashes and the main odometer stopped incrementing too.
Reading how the ABS controllers are notorious and that a bad one can cause seemingly unrelated running problems by sending bad info to the ECU, I removed the ABS controller, and disconnected the battery for an hour hoping that would reset the ECU and only the brakes would be an issue. Am I right that the ECU would recover from limp home mode after being depowered? In any event, there was no improvement in the dash displays or running behavior. My OBDII reader showed no codes after this, but I know there can be codes my simple reader won't show.
I plan to resolder the ABS control anyway when I have time so it is still out of the car and of course the message now says "Brake failure, stop safely ASAP". Driven the car a couple of hundred miles since then without noticable change.
The car continues to show no temp on the gauge and the fan runs on for a couple of minutes after the engine is turned off. It is quite hard to start and harder the colder it gets (5 degrees is the lowest so far, but after much cranking it finally caught and started.) It always runs badly, but worse immediately after you get it started, with much surging. Engine seems to hunt constantly even after warmed up (and it is warmed up since there is plenty of heat.)
So now I'm thinking either the ECU is bad and accounting for everything or I have the unlikely coincidence of the ABS controller's STC circuit failing at just about the same time as the my coolant temp sender went bad and all the running issues are caused by the car having no idea what temp the engine is at.
I hope to get at the temp sender this weekend and test it, but honestly I'm leaning toward a bad ECU at this point and I know that's an expensive replacement which may not be worth it. I'm hoping someone may have seen something similar or have other ideas since after a long line of Volvos, I've had this car for a couple of years and like it very much.
Thanks in advance.
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You know how you drop a little tool and it disappears inside you engine bay never to be seen again? Sometimes that can be a good thing. Especially since the one I dropped was just a T25 bit.
When I got down to look under the car in a fruitless hope that it was on the ground, I saw two wires dangling to the ground. That can't be good. I know an oil change or two ago, I say that a couple of different wires were hanging down some and zip tied them up better. It appears I didn't do this one well enough or a snow bank got it. It sure looks like it would go to an 02 sensor and I found this post which doesn't make me too happy so far.
http://volvoforums.com/forum/volvo-s80-18/2000-s80-o2-sensor-problems-possibly-others-28742/
So I guess I have to try to splice in some new wires, hope I get them connected properly and then hope my ECU isn't bad because of this. Doesn't seem likely that a missing 02 sensor is going to make my temp gauge stop working though, does it?
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Well what a small world. This car was sold to me and now I have the problem. I replaced the Etc for $500 the turbo boost sensor the temp sensor and thermostat and still no change. I tested the wire from the temp sensor to the ECU and they checked out. So is it the ECU not reading the temp sensor? It has so many codes on it. It also won't read the turbo boost sensor and that's new. I'm super frustrated with this car.
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That Volvoforums post was really enlightening! And a bit scary.
Yes, the rear O2 sensor will cause a limp home code, but after splicing it back together you need to clear the codes and see if that one comes back.
A burned ECU... My first encounter with that. Should I say beware of early S80s?
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My back feels better when I sit in a Volvo seat
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I'm not yet convinced the ECU got shorted and burned, but maybe I'm just in denial since that's certainly plausible. Had 8 codes after a long drive today (seemed to run and shift better, but not certainly not right). Not sure how many it can store. It was a laundry list that included not just one, but two 02 sensors. Tried to clear them, but three would not clear with my simple OBDII tool which still leaves me wondering if there are VADIS codes stored which will not let it out of limp mode until they are reset and further if driving in limp mode can then set more codes.
Regardless, unless just driving it far enough with the O2 fixed (if it is fixed) causes the car to realize things are OK, then I will take it to a shop next week to get a verdict and they will be able to read-reset VADIS. I'm willing to spend for that diagnosis, but if the cure is a new ECU and that's $1200, then I think I might just have to be satisfied with the trouble free and relatively inexpensive couple of years I had taking this car from 170K to 204K. That would be a shame since it's otherwise a nice car, but an oil leak and AC not working make it hard to invest $1200 in it rather than into another used car.
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Hmmm,
Mercedes:
http://minneapolis.craigslist.org/hnp/cto/4781153614.html
http://minneapolis.craigslist.org/hnp/cto/4750953120.html
BMW:
http://minneapolis.craigslist.org/hnp/cto/4769517908.html
Volvo S60:
http://minneapolis.craigslist.org/wsh/cto/4777194318.html
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My back feels better when I sit in a Volvo seat
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Update:
Since hope springs eternal, I carefully spliced the wires to the left rear Oxygen sensor. Heat shrink wrap and electrical tape in hopes of keeping water out long term. The wire is shorter now, so doesn't route like it should, but some zip ties are holding it up tight. I'd rather not have it on the bottom at all to get whacked by the snow, but I'm also not in a hurry to spring for a new sensor until I find out the long term prospects for this car.
The only noticeable (and inexplicable) change is that the trip odometer started displaying and the main odometer started incrementing. I think it ran somewhat better, but that could be my imagination. Had left the battery disconnected overnight to clear codes (though I'm not certain that works and would like to hear one way or the other.)
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https://www.midwest-abs.com/S80_99-2001.php
Read what he says about the 2001 S80 ABS module. Good.
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My back feels better when I sit in a Volvo seat
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Thanks, Klaus. That site has a lot of good info and it's one I hadn't seen. Especially showing a part # that is NOT trouble prone could be helpful. I think my unit has a number starting with 9 though. Since it's still out of the car I'll check that when I get home. But my symptoms don't fit the stereotypical ABS module failure and I think I've about eliminated that as my issue.
I think my analysis is going to come down to testing my coolant temp sender. btw, for anyone reading this, it's in the cover of the thermostat which is under the plastic cover for the timing belt on the passenger side (North America) of the engine. I had a little trouble finding that info.
If my temp sender is good, then I think all that's left is my ECU to blame. The ABS module is out of the car with no improvement. the DIM in the dash causes display issues, but not running issues from what I've read. So if my temp sensor is good, then I think my gauge showing always cold, my lack of clock and odometer and all my running issues are due to an issue with the ECU.
I'm willing to pay a shop with VADIS (not the dealer though) to try to confirm that and also answer the question as to whether codes can be stored there, forcing limp mode and which are NOT cleared by depowering the ECU and so must be reset via VADIS before you can run properly again even if the original issue is gone. I doubt it though since I haven't seen any reference to that situation on the web. If anyone knows for sure whether or not depowering, or driving a significant distance without remaining real issues will clear limp mode, I'd appreciate hearing that.
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I would blame the ECU last. First on the list is the DIM and CEM computer boards. That's why you need to get the Volvo codes. Remember, the CEM (Central Electronic Module) is nothing but a data buss or router, sending the signals to the proper destination. If there is an error or a bad weld, well too bad...
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My back feels better when I sit in a Volvo seat
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Didn't know about the CEM, thanks, but all I've found about the DIM is for a bad one messing up the dash displays. Haven't seen anything about a bad DIM creating engine starting/running problems. Do you have info that the DIM can get in the way of info to the other components and so create issues like mine?
btw, it turns out I have the brake controller part# which Midwest ABS says almost never fails (thanks for that link!). So I'm going to put that back in and assume that the theory that this was the original root of my issues is bogus even though the original message was about STC.
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ALL of the communications goes through the CEM. The only way to isolate the CEM as a problem is to do a computer scan, via scan tool. Besides, that is an expensive part to throw at a problem as a guess. A new CEM is too costly to replace and will probably fail in 10 years or less, Xemodex is a better alternative.
The DIM is known for failure, but it will not effect engine performance.
The speed signal goes through the ABS and that effects a lot of engine driven parameters + the odo and speedometer.
A lean/rich fuel mix can also be caused by a vacuum leak, degradded MAF, or even throttle control/TPS.
When you get the codes read, write them all down. And have them check the seat computers and clear any messages stored there while they are at it.
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My back feels better when I sit in a Volvo seat
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Don't tear apart the ABS controller just yet. Only do that if you did have the ABS/STC lights on. Plug it back in and see what happens. The ABS codes will NOT reset with power off.
You have no temp gauge but does the thermostat work? Is the upper radiator hose hot? A failed temp sender will present all sorts of problems as the ECM will be told the engine is either real hot or real cold.
Your 2001 could have a problem with the DIM, driver information module better known as the instrument cluster. But without a good code reader, you won't know.
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My back feels better when I sit in a Volvo seat
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Thanks for your reply, Klaus, I have plenty of heat in the car once the engine warms up, so I know the antifreeze is getting hot and I'm not thinking my thermostat is stuck open. Besides, that would only create an issue after warmup (or what should be warmup), but mine is there and worse at startup.
I had seen mentions of the DIM, but didn't know it was in the instrument cluster. I guess that could be my issue too. Just one more computer to go bad and make craziness.
The one issue I can't think how to pin on a possible bad coolant temp sender is that the odometers aren't working.
It happens that I also have a 2000 V70 which uses the same temp sensor and the same ABS controller so I can swap those parts for testing if I can find a day when both cars can be laid up. I've been leery of putting the ABS controller from the S80 in the V70 though because of my original theory that bad ABS info was causing everything else. I think that theory is fairly discredited at this point though.
If I prove that my temp sender is working then I guess I'll have to pay Glasgow in Saint Paul to give me more bad news.
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If it is the DIM, visit Xemodex.com
Also look at their ABS repair. I am not sure if https://www.midwest-abs.com/ does the 2001, but he is cheap and fast.
Swapping the ABS modules with the 2000 just might work and is worth a shot. Especially if the temps get above 32F like the weather folks promise :>)
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My back feels better when I sit in a Volvo seat
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