I looked on the Tech Folder and did not see what the 12-06-05 TSB that is fixing the problem. I read through all 16 pages of the Exhaust fluid system fault thread. Look it be possible to get a copy 12-06-05 TSB or am I overlooking something in the Tech Folder. I have a 2012 F250 4x4 CC Lariat with 6900 miles and got the 50 mph Exhaust fluid system fault. Local Service Manager said has not had a truck come in with this error. Dealer is in Marble Falls, TX.

 

That is the latest and the one that fixes the problem. I have been unable to find a copy of it.

As I said, it will fix the DEF system fault, BUT... it will increase the number of active regens and decrease your mileage a bit - about 1 to 1.5 MPG. In addition, you'll lose some of the "hot rod" like performance that your truck currently has. You won't lose any true working or towing power, but the kick you feel during a jack-rabbit type launch is going to be softened a bit.

I want to take this opportunity to state what I think is going on with TSB 12-06-05. As we all remember, prior to this TSB the normal course of action on the part of the dealer for the DEF system fault was to replace the NOX module/sensor, sometimes not until after our 2nd, 3rd or 4th complaint. Sometimes it fixed it, and sometimes it didn't. Now the TSB is used almost exclusively to fix this problem. Some believe that the NOX sensing parameters have been loosened up with this TSB. I really doubt that that is the case. Changing these types of parameters would require some fairly extensive EPA testing. I believe that the fault is due to a real emissions performance issue. The truck really is exceeding EPA mandated NOX emission levels!

Think about it.

NOX is generated during high combustion temperatures. Add more fuel at the appropriate time during the combustion cycle and you reduce NOX. Unfortunately, what is good for the goose, is in this case not good for the gander! NOX reduction and soot reduction are mutually exclusive. Cooler combustion temperatures to meet NOX emission limits creates more soot, which then requires more active regens. A leaner burn reduces soot, but increases NOX. A richer burn reduces NOX but increases soot! Hmmm! What a conundrum! If your SCR system is unable to control NOX emissions due to some physical shortcoming, what do you do? You make adjustments to reduce NOX via a simple software change, then let the active regen system handle all the dirty work. More regens? Who cares? We don't have to meet any mileage requirements, but we do have to meet EPA emissions.

I may be all wet here, but this is what I truly think has happened. Why else would you reduce one of this truck's claims to fame, it's MPG, unless you absolutely had no choice?

 

Damn your smart Romeo. Sounds like a good explanation to me. I just had the TSB 12-6-5 done to my truck yesterday.

 

Service Manger called and said he is going to just replace the DEF pump and reflash the truck. He said this would fix the exhaust system error. I asked him if the Nox sensors needed replaced and he said no.