| Author |
 Topic  |
|
|
Thomasbus24
Administrator
USA
4547 Posts |
 Posted - 03/14/2018 : 04:55:50 AM
|
"2012" Blue Bird AAFE, built December 2010, just under 100,000 miles of very, very, very, very reliable service...
Driver is heading home after morning route last Thursday when the engine warning alarm goes off and "SCR FAIL" on dash readout. She comes back, we have a code for abnormal update rate on the DEF system.
Find blown fuse in PDU for the constant battery power to SCR system. Try new fuse for fun, immediately pops. DVOM shows short to ground on the harness after leaving the PDU, even with dosing module unplugged. At this point we didn't realize these things even had a separate controller for the DEF, so we didn't unplug anything else.
Cut 14,762 zip ties, trace wires, find nothing. Dead short now gone, fuse holds, still have the code. Neighbor give us tip to print off info from Quickserve, we follow the diagnostics, which lead us to the controller.
Disconnect controller's 2 plugs, find thermal damage seen here... https://www.flickr.com/photos/27265743@N03/albums/72157666654007848
Dealer has "never seen that before" yet they have sold 5 harnesses for the emission systems in 12 months (now 6 since we needed one). Did I mention it was in stock? Interesting. Cannot buy just the plug and pins. Changing the $1000 harness isn't really all that bad. New controller should be here today.
Anybody seen this before? I consulted another authorized Cummins dealer who said just change the harness and controller and it'll be fine. Still has me worried. |
|
|
exmod110
Senior Member
151 Posts |
Posted - 03/14/2018 : 05:39:05 AM
|
| No issues here yet, but I find it very funny that "never seen this before" and "the parts are in stock" go hand in hand. |
 |
|
|
Thomasbus24
Administrator
USA
4547 Posts |
Posted - 03/14/2018 : 07:20:36 AM
|
I'm just worried that we will plug the new control module in, fire the bus up, and melt it down just like the last one. I can't find any legitimate reason for the failure, other than maybe the crimp connection in the plug was loose, thus resistance.
New harness is installed, just waiting on UPS to get here...and wondering if I should replace the dosing module. |
|
|
|
drp53188
Senior Member
89 Posts |
Posted - 03/14/2018 : 10:37:27 AM
|
Look in the doser pump connector on the pump is it green ?
Any repairs to the SCR system you MUST let the system run it`s selftest for one min. before the fault will go inactive and you can then clear the code.
If the pump connector has any green in it junk it , you have DEF leaking from the pump inside, also all my bluebirds have wiring problems at that mileage but i live in the salt belt. |
|
|
|
drp53188
Senior Member
89 Posts |
Posted - 03/14/2018 : 10:39:55 AM
|
| Buy the way you can buy the pins / seals / hardshell connectors and cummins will give you the part numbers in quickserve |
|
|
|
Thomasbus24
Administrator
USA
4547 Posts |
Posted - 03/14/2018 : 11:48:56 AM
|
Doser shows no corrosion or leaking into the plug (we've lived that dream before).
Thanks for the tip for next time on the plug...yet another line of BS from our dealer. I'll add that to the list. |
|
|
|
Rich Michels
Active Member
12 Posts |
Posted - 03/14/2018 : 6:40:32 PM
|
| I know yours is a AARE, on our 2014 DRE's I had a random SCR heater line codes, which would blow the fuse. Our dealer tipped us off that the wire harness for the SCR comes across the top of the engine compartment and drops down to the PDU. The wire harness comes across the left rear corner of the PDU, ours rubbed into the harness. I've since installed a stand off to hold the harness away from the box on all of our DRE's. |
|
|
|
Thomasbus24
Administrator
USA
4547 Posts |
Posted - 03/15/2018 : 03:11:56 AM
|
| Oops, sorry folks...AAFE here. I corrected the original post! |
|
|
|
bluebirdvision
Top Member
USA
1081 Posts |
|
|
Thomasbus24
Administrator
USA
4547 Posts |
Posted - 03/15/2018 : 06:38:40 AM
|
Mentions what? The harness/plug melting?
Got the new harness and control module in...still have the abnormal update code. Can't get the pump to run, thinking it either was taken out by the control module failure or caused the module failure. Both buses on each side of the age of this one have failed their dosing modules, so no shock there.
LP sounds better and better every day.
|
|
|
| |
Topic |
|
DEF module meltdown
