I never saw the movie Failure to Launch, but unlike the main character in the film we actually WANT to leave our house but can’t due to mechanical issues. To recap:
- We bought a used 2011 GMC 3500 truck on Dec 8 after the dealer had dealt with a check engine light related to the exhaust system (I know, I know….it sounds so stupid now but I did it). They replaced the DEF injector and NOx sensor #1.
- On Dec 21 after 57 miles the check engine light came on and we took it back to the dealer
- $800 later we had a new DEF tank and heater and were rolling again Dec 27.
- After about 150 miles the check engine light comes on again Jan 6
- After a week in the shop and me calling every day to figure out what they found, today (Jan 13) they say that the catalytic converter (aka SCR), diesel particulate filter (DPF) and NOx sensor #2 must be replaced to the tune of $4200. Oh, and it will take a week to get the parts.
My first reaction is that I feel like I was sold a vehicle that was known to be bad. I want justice. Three check engine lights in 200 miles….there is no way this JUST started happening now. I don’t think there is anyone to blame but me. With a check engine light I should have stayed far away!! But still I feel like somebody knew this was a lemon.
My next reaction is to ask, is that REALLY the problem? The current error is an “exhaust fluid quality poor” message and I believe the tech is following the procedure laid out in PIP5007. When you get to the end of the procedure it says “If all conditions above appear to be functioning normally, SCR replacement may be required but is a very rare occurrence” (emphasis added by me). If you read the entire PIP5007 forum topic linked above you will find many who say just replacing BOTH NOx sensors usually fixes the problem. And it seems to make sense. From my understanding of the system (about half way down the page here is a description and diagram) a properly running system will have a large delta between NOx sensor #1 (at the beginning of the exhaust system) and NOx sensor #2 (after the SCR). When there is a small delta it can mean that the SCR is bad….but the engineer in me says it could also mean that NOx sensor #2 is bad. Compared to the DPF and SCR, the cost of the NOx sensor is wiz in the ocean. So perhaps we just replace NOx #2 and see if everything tests out? Where in that document does it say that the DPF should be replaced?
My third reaction is to ask, do I cut my losses and trade the thing in for something else? But this just seems so wrong on so many levels. Such a waste of money.
Maybe I suck it up and have everything replaced. Then I have an entirely new exhaust system. It should come with a hefty parts and labor warranty from GMC so any other problems with it will be covered right? Like I’m buying an extended warranty on the exhaust system. By the way, we did purchase an extended warranty for the truck. I really did not want to but since I didn’t want truck issues to spoil our trip, I bit. Its a great plan except for the one extra page that says “diesel exhaust system not covered”. Have I told you how I believe bikes are superior to the automobile?
And your reaction is probably, (a) you should not have bought that truck in the first place and (b) if people read this blog they won’t after too many posts like this one. Touche!
So let me wrap up with the good. Our family is happy and healthy. We have awesome family, friends, and neighbors. I have a job. We live in a free country. We have plenty of food to eat, clean water to drink and comfy shelter over our head. We even have a renter (not a done deal yet but looks really good!!).
As cars become more complicated and I have less and less time I struggle with working on my own vehicles. So far, other than a tranny and having a key made ($100 and 1+hour wait in a crowded waiting room with no seats left, for a key!!), I’ve managed to avoid the pain of an auto shop. I cringe at the very thought of having to take my car to someone. No mechanic, especially a dealer, is going to read forums of other peoples experiences, research the parts and designs like you have. He’s going to follow the cookbook and if at the end it says replace the whole thing that’s what he’s going to tell you to do. Do you really think he wants to continue diagnosing your issue while his manager is on him about spending too much time on one vehicle? Your hard drive has errors and after all the tests Microsoft says to replace the HD and motherboard. How about we just start with replacing the HD for an easy win! In my opinion, you know I’m cheap, I’d start with NOx sensor.
Also, sorry to hear of all the difficulty with getting going. When things go like this I like to think the good Lord is delaying you to avoid an even bigger event. If you have a flat tire maybe it’s just His way of keeping you out of an accident 5 miles down the road.