I am a mechanic and struggling to figure out this problem with a 2012 f350 6.7 4x4 truck I am working on. The truck automatically engages the locker when turned on. It's a base module with a switch that only turns the locker on, it's a floor shifted 4x4 model. I am getting two codes. U3000-49, which reads control module internal electrical failure, as well as P189A-00, Axel disconnect input switch circuit low. A new, used, switch has been installed and nothing changed. The locker is disengaging when the truck is turned off as confirmed by spinning the wheels when raised. Anyone run into this problem? New TCCM at this point? I'm assuming it will need a reflash at the dealership as my Snap-On reader cannot perform this function.
Doozy.pup
I’ve not had this issue before. Have you wrang the wires out to make sure you don’t have any shorts to ground causing it to engage without the switch being activated?
I am working on that, I have tested for continuity for all wire in the system and have confirmed that they have it. All wires go from switch to TCCM, except one. A purple and grey small gauge wire goes into the fuse block on the passenger side. If I understand the system correctly, wouldn't a short to ground cause it not to work? Since it applies voltage to lock the mechanism and not to unlock it?
Without having a schematic in front of me and knowing what kind of circuit it is… it’s hard to say. But if you’re shooting for continuity from one end to the other and not reading through anything that will cause resistance then you’d know if it’s shorted to ground or not.
So I just watched a really interesting video where a guy swapped a 2012 diff with E Locker into a 2006 housing. You’re correct. When power is applied, it locks. He actually ran a battery straight to the locker wiring and put a switch in between. It locks and unlocks with just 12 volts dc applied and removed respectively. Maybe that’s worth a try and take the TCCM out of the loop. If it works, then order a new TCCM. If not then it’s back to the drawing board.
Two possibilities:
- U3000:49 - TCCM Control Module: Internal Electronic Failure CLEAR the DTC. REPEAT the self-test. If DTC U3000:49 is retrieved, INSTALL a new TCCM - To be honest you really should start with this.
- P189A-00 - Axle Disconnect Switch Circuit Low - will require testing the switch and the white/green wire from the switch to the TCM - I would address the U3000:49 code first. Sending a PM.
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
