[IndyDiesel]

Finally got the diagnosis - DEF reductant tank reservoir heater needs to be replaced. I thought that might be it, but odd no CEL.

Did they give you an estimate of cost of replacement of the def Heater Reservior? More curious than anything.

 

[IndyDiesel]

A couple of years ago I had this warning with no CEL ( I had already been thru the failed heater prob, couldn't get one so took it to the dealer where they could get one next day, they told me they swapped out the reservoir but they just unplugged and swapped out he drop in part, I learned long ago to sharpie the parts before they SAY they replace them). I wasn't aware of shelf life considerations on the DEF. I googled the way to decipher the Peak DEF fluid code so I was sure to get the newest I could then siphoned out the existing fluid and replaced with new. warning went away and didn't return for a long time.

Fast forward to one month ago I get the poor def warning and the subsequent countdown, no code. I always get newest fluid I can, usually at local farm store. I topped it off with about 2 gallons of Peak DEF with Date code representing mid November, so really fresh. Warning went away immediately. 2 weeks later warning returned. I siphoned all of it out and replaced with the fresh and warning goes away immediately.

Now, 2 weeks later, warning is back, no CEL. we are at 98K on the odometer. Could my problem have any thing to do with the recent sensor and regen letters we received? I don't recall ever seeing any notification about a regen running, never inquired at dealer about one. I have had bad luck with dealer for problem diagnosis and paying for unnecessary parts before. I really hate to go there for anything. If I need to go I will find a different one.

Sounds like it could be the DEF heater issue, it has a private letter good for free replacement if you are having the issues you are having, they should replace the def heater and whatever goes with it for free, it was 10 years and or 120k miles as I recall. Take it to a dealer that knows what they are doing and services diesels.

 

[IndyDiesel]

no codes. limited to 65MPH. Took it in with the recall letter for NOX 1 sensor/ECM update/regen. figured that may get rid of the "Diesel exhaust fluid poor quality" warning and limp mode. no luck. still had the same warning. sat in the dealership for 7 hours, no progress, no codes. Left it there over the weekend.

This am they called me and said they determined that the problem was with NOX 2 sensor. Still no codes. They could change that for > $900. That amounts $500 for the sensor and 3 hrs labor. They recommended flushing the trans and cleaning the battery terminals also but that would run me about $1300 all together.

I am infuriated. took a number and told em I would call back. been steamed all day. I can't see how they can quote 3 hrs labor for a NOX sensor that is sticking right out at you. unless they are charging for time spent guessing at why the recall work didn't get it out of limp mode. ARGH! Probably another part I am unable to readily buy outside of the dealer like that DEF tank heater.

Online the nox sensor is about 230, I would consider doing it myself. Sounds like they are not being fair on price in my view, I think GM has a screwed up emission system that is too darn expensive to fix out of warranty.

 

[IndyDiesel]

The speed limit/poor DEF quality issue is extremely likely the DEF heater. They are apparently not doing a good job of diagnosing it. That repair is covered under a 10 year 120K mile extended warranty. I am 99% sure that's what the issue with your car is. My dealer was able to diagnose without a CEL present.

The NOx sensors do NOT contribute to a speed limit message, based on all the info I've gathered, and 4,000 miles on my car with an on-and-off P11DC (NOx #2) CEL.

if this dealer misdiagnosed the issue which is a definite possibility, how are they going to put this emission system or something similiar to it with the gen 2 ctd in so many cars, the dealers don't seem well trained on this system across all dealers. Very disappointing to be honest.

 

[IndyDiesel]

That's awesome that my suggestion worked!

And yes, it does feel like you are going to break something, but I've done that many times over the past 199K miles, and nothing has ever broken as a result. It's been at least 2000 miles since mine cleared and it hasn't returned.

Only thing I would add is if you drive for an extended period like this wide open, after you are satisfied you have done that long enough, might be a good idea for some easy driving after to let the turbo cool down,it has to be very hot driving that hard, can't imagine driving 10 plus miles effectively full throttle and pull into a garage And just shut it off so hot.