Service Exhaust Fluid System message

[Jesse1975]

I'm in the middle of the countdown condition and about 85 miles away from being limited to 4mph. Service Exhaust Fluid System is the only message. No DTC's, no check engine light. Truck is in middle of a regen, which it started with only 10g of soot on the meter. Had the DEF heater replaced today, that cleared the P21DD and P20B9 codes that were in it, added some DEF then regen started. Drove 25 miles to help it, did nothing.

https://www.techconnectcanada.com/blog/2016/03/diesel-exhaust-fluid-basics

That link scares the $#!+ out of me, looks like it knows I had a tune (mild, fuel efficiency based one) and it's out for revenge. I loved the tune but had to go back to stock as Mass Inspections are brutal now and more states are going that way. I'll keep up with this thread to let others know how I make out.

Anyone with any ideas, it would be greatly appreciated.
Thanks
Jesse

[Jesse1975]

I think I found it, the heaters need to be toggled on for a test, can be done by a dealer or shop with an autel or other professional scan/program tool. After successful heater test the condition clears, hopefully. I'll update tomorrow for others who find themselves here.

[DmaxMaverick]

Disconnect both batteries and ground one Batt+ cable to chassis for 30+ minutes. This should reset all the counters. Once started after, all the diags will run. You'll have to put some miles/time on it before the inspection, as it will fail until all the diags run and complete. If that doesn't work, it will have to be reset by the dealer or competent shop. Also, the regen needs to complete before it reruns the emission diag PID's.

[Jesse1975]

Thanks for the response and I'll remember that one. I got a call for work and had to head out last night and the countdown continued. Then with about 30 miles until 4mph, it cleared and normal operation resumed. It had completed the regen and has no codes presently.

To people like me who are cruising the net looking for help with their trucks and came across this page: if it helped you and you can spare a few bucks, BECOME A MEMBER. It's not a lot, free advice like this is priceless. I did last year, and that was after first coming here about 12 years ago with a different login name that I forgot. The people here are great and put time and energy into making this a good forum.

Thanks again thedieselpage

[DieselDavy]

I don't have one of the newer trucks, so what does this mean:
"Then with about 30 miles until 4mph"
"85 miles away from being limited to 4mph"
d

[DmaxMaverick]

I don't have one of the newer trucks, so what does this mean:
"Then with about 30 miles until 4mph"
"85 miles away from being limited to 4mph"
d

The computer will reduce power (and some features) if/when there are significant problems or is unable to run maintenance cycles with the advanced emission systems (DPF and/or DEF), to protect the related system(s), and the powertrain. Essentially, it's a limp mode with a progressive countdown to the next stage of limited power. The "4 MPH" warning may actually be a bluff. I've seen a couple trucks an a car (2018 Gen 2 Cruze) reach this stage, but they were still able to drive at 30 MPH+ for quite some miles, never limited to 4 MPH. I've not heard of any, either.

[DieselDavy]

Thanks Dmax!