My truck is stuck in low range (low range light is on). It drives like a bus and won't shift. Occasionally, the low range light turns off by itself when cruising for ~3 seconds and it can shift again, only to turn back on right after.

These are my codes:

ETC
041:

"[One or more messages from control unit N78 (Transfer case control module) are intermittently not available on the CAN bus or the transfer case position is position is intermittently implausible.] or [One or more messages from control unit N78(Transfer case control module) are not available on the CAN bus or the transfer case position is implausible.]
DTC Status: Resistance too low"

137:

"One or more messages from control unit N78 (Transfer case control module) are intermittently not available on the CAN bus.
DTC Status: Resistance too high"

AAM
B1040-003:

"CAN BUS: communication control: N78(distributor drive control module)
DTC Status: Stored"

I have tried clearing the codes, but they still remain. "Low Range" Light is on 99% of the time. I read somewhere that I must replace the transfer case motor (as they are prone to fail). Is this correct? If so, is there an updated transfer case motor (where they corrected this flaw and what is the part number)? Should I get a genuine MB part or an aftermarket like Dorman? When installed, do I have to clear the codes again or is there just gonna be no "low range" light?

Thanks in advance.

 

How did this problem occur? Did you purposely try to activate Low Range? Did you spill liquid on the console?

 

I never activated it myself. I know it sounds strange, but it turns on and off by itself. The low range light turns on and turns off for like 3 seconds at times. (Without me putting it in neutral) During those 3 seconds, I could shift normally again. I did not leave my sunroof open nor have a spill my drink onto the console.

 

Try this, with the key out of the ign., remove fuses 18 & 22 in the under hood fuse box. Wait 15 secs. and reinsert then and see what happens.

If the problem still occurs, you should replace the Transfer Case Module with a used one. Vin# needed.

 

I'm out for the week; I'll try this when I get back. If it is the Transfer Case Module, and I have to replace it with a used one, do I have to have it VIN coded? Or is it just plug and play?

 

It's plug & play.