Hey guys,
So I've got an active code P1876, Transfer Case 2WD Soleniod Circuit Fault. Thanks go to Tugly for making a road trip to my place and pulling old codes resetting and finding this one that came back! So anyway, read one here about unplugging the harness and checking for oil, it's dry as a bone. What would be next?

 

I was reading up on this and I found a couple of references to a bad transfer case motor or a bad ESOF module. That long-running vacuum motor makes me wonder about the ESOF system. Is your cab vent stuck on defrost by any chance?





BTW... I don't know what your schedule looks like next weekend, but I'm "floating" a bit with that rally in Plain.

 

Does your 4x4 work? I also have this code but the 4x4 still works, although I can't say if 4low works. The compressor also runs quite a while on first start of the day. I figure that it don't seem broke so why fix it.

 

So I just re-confirmed 4X4 works and quickie vacuum leak check....start truck, put HVAC onto floor mode, switch to 4 hi, can't turn axels at u-joints, HVAC still on floor, brake on and shift to N, switch to 4 low, audible "clunk" of engagement, shift back to 4 hi, audible "clunk" of disengagement, shift to 2wd, after a few seconds for vacuum level to bleed off u-joints spin free...huh...Seems I read in a thread last night where Robin had had the code, checked relays and "polished up" relay terminals and problem went away. Are relays K378 and K379 located near brake booster?

On another note, I'll be hanging around the homestead this weekend Rich, I'm on-call for work.

 

I've searched the whole wiring diagram and cant find the location of the relays, but I read that they are located where you suspect.

I'll see how things play out this weekend, this rain is wreaking havoc with the cherries... helicopters and orchard sprayers are running at all hours. I don't know what this will do to my work schedule.

 

I'll see if I can locate them and get them checked. If I'm reading the wiring diagram you posted correctly, depending on ESOF switch position, the 4wd module energizes the appropriate relay and voltage polarity reverses. If I'm recalling my basic electrical theory properly, in a DC system, the would drive the solenoid motor one way then the next based on switch position and polarity...sound right to you? If I can make it home from work before 8pm this week I'll check voltages, polarity and Ohm the motor.

Know what you mean about the cherry harvest...been running up and down 97 from E-town to Pateros last couple days, lots of wind machines running...not good on an already smaller harvest year! Around here, there's quite a bit of hay that didn't get bailed before the rain. On a good note looks like we're gonna turn the weather corner tomorrow or Thursday!

 

You "get" the Hi/Low motor function. The ESOF just receives instructions from the PCM like the Hi/Low motor does... be one does not "effect" the other.

Pateros, eh? I'll be at the packing plant 1/4 mile North of the Beebe bridge today, but I'm usually at the plant above the bridge.

 

I'm thinking the issue is in the PVH solenoid. Using your super-secret link and all the wonderfulness in there, used diagnostic guides and found no resistance at PVH solenoid coils. There were a couple other things I wanted to rule out, but when I checked the resistance of the solenoid, the given value should have been between 45-55 ohms and they were open. Now I need to find the current part #.

 

That would certainly throw a code. Great job!

 

Stumbled on this thread.... as I have the Code 1876 now with Two-wheel Drive open circuit open / short ?

I just replaced the shift motor and the 4x4 does engage. As stated above, I have notice the vacuum motor seems to run for a long time, at least two cycles of start up glow plug light.... that may be normal ???

I switched to manual Warn hubs years ago and capped off the vacuum lines to the wheels at the vacuum pump. Heater door works, so I have vacuum there.

Any thoughts out there ?

 

After looking at this a bit, why can't I just unplug this PVH solenoid, since I have manual hubs and this no longer locks the hubs?? Is that going to throw a hard code then ?

 

Bill, unplugging the ESOF hub solenoid will not cause the CEL/SES light to cone on. Although, it will probably not clear the soft code either.