S70 Loves to Be in Limp Mode, Dealership Clueless

[dcarlson12]

Do you still get no DTC codes when it is in limp mode? i.e. when you limped it to the dealer, did they not find any codes?

[BEJinFbk]

I think you may have already answered your own question.
You stated that you have nasty battery cables. They may need replacement.
These cars are getting old enough that unseen damage to the cables may be
affecting how well your car keeps the battery charged and the system voltage up.

Since you have an electronically controlled engine and transmission, weird things
will start to happen if you don't provide good, solid power. Check ALL of your
cabling and be sure that the battery and alternator are up to snuff.

And if the dealership wasn't keen enough to check this out, you might consider
looking for a good, independent Volvo mechanic for a quote. Unlike some dealerships,
those indy guys stay in business because they know what they're doing.

Good Luck!

[Carly245]

All of the codes in my car have been wiped out, and they have been for a while. My dad was on the internet and he found some articles about how replacing either the battery or the alternator (I had to do both about a year ago) can result in an accidental code wipe out, and coincidentally all of these problems happened after I got my battery and alternator replaced. So the Volvo dealership doesn't know what to do, and I took my car to an indy guy who exclusively services Volvos, and the answer I keep getting is, "Well since there's no codes, we don't know what is wrong, we don't know where to start." So they fixed the obvious thing which was the corroded battery cables, and I would hope that they checked all the connections to the battery/alternator as well. So it's just been a long run of trial and error, and I'm taking this car into a very reputable mechanic on Monday, Volvos aren't their specialty, but they've been around for over 30 years and if these guys can't can't figure it out, then I'm done!
Maybe I should ask this question: if your car's codes have been completely wiped out, how can you get them back? But I'm afraid I already know what the answer is....
Thanks everybody for helping me out!

[BEJinFbk]

Again -Before you go any farther, be sure the the electrical supply is stable.
Battery, Alternator, Cables - Everything. Especially the B+ supply cables that run
from the battery to the fuse boxes. This doesn't require any codes, just common sense
and the knowledge and ability to use simple meters. It aint rocket science...
A mechanic that knows the ropes should be able to do this in minutes.

Unfortunately, it seems like there are more and more wrenchers out there that
have never learned about the basics. They've become so dependent on "codes"
and repair software, that they don't know how to check the obvious.
But be assured, the good guys are out there!

[Carly245]

So we took my car into an independent shop, and they ran tons of tests on it, and somehow got some codes out of it. The mechanic concluded that there's a connection issue with the ETM and something else, and he doesn't know what that something else could be, and he's not ready to say for sure that we need to replace the ETM. BUT...my car has been sitting in the driveway for a few weeks and last week I tried to start it and the engine wouldn't even turn over or start. I tried starting my car a few days ago and it still won't start. So what does this sound like? Is it total ETM failure? Is there a progression in ETM failure, from random stall outs to more frequent stall outs to finally a car that doesn't start at all? What's going on here?! And can it also be the MAF? When I google "ETM", "MAF" comes along with the results.