When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
My truck does mostly pavement duty so no telling how long ago 4WD quit working but I needed it the other day and it's now a no-go. It's the '06 truck in my sig and it has ESOF.
When I flip the switch (4hi or 4low acts the same) my A/C continues to come out of the dash vents, it doesn't change. With KOEO I can hear a whirr-click from under the truck when switching 4wd on and off, I get noise both ways. 4x4 light on the dash seem to work correctly.
Broke out FORScan and got the following info:
===GEM DTC P1832===
Code: P1832 - Transmission Transfer Case 4WD Solenoid circuit failure
Module: Generic Electronic Module
Diagnostic Trouble Code details
Transmission Transfer Case 4WD Solenoid circuit failure
===END GEM DTC P1832===
===GEM DTC P1876===
Code: P1876 - Transfer Case 2-Wheel Drive Solenoid Circuit Open Or Short To Ground
Module: Generic Electronic Module
Diagnostic Trouble Code details
Transfer Case 2-Wheel Drive Solenoid Circuit Open Or Short To Ground
--- Possible Causes --------
This DTC can be generated by:
--- Possible Causes --------
P1812 can be generated by:
-Open 4-Wheel Drive Mode Switch
-Suspect 4-Wheel Drive Mode Switch
-Suspect Generic Electronic Module
NOTE: For Vehicles with 4x4 Option
If you encounter this code when you are in 4x4 Low mode, rerun the Self-Test in the 4x2 High mode. If you still generate code P1812, there is a 4-Wheel Drive Switch/Circuit problem.
===END GEM DTC P1812===
Any tips to quickly nail it down between the switch, GEM, wiring or solenoid? Looks like the whole thing is failing- lol. I've climbed under the truck and all the wiring appears undisturbed. No recent work under there. In FORScan, these DTC's were generated in a user iniated test and I didn't pick up the instruction to re-run the test in 4x2 mode until I posted just now.
Under the hood everything seems to be routed correctly and connected. Vacume pump runs a short while on start up like always has. I can lock hubs manually and they don't seem to be binding hard but they are a little stiff, haven't done that before so I don't know how hard it should be to turn them. I have a MiteVac but haven't tried using it to try and lock the hubs. Not sure any of that matters (yet) with the DTC's listed above.
Picture just to be sure I'm in the right place. 0 continuity between any of the three pins in this device. Didn't check on the harness side. Thanks for the reply Cheezit.
No problem.
Most of the time the 4x4 relay code are bogus.
You can pull the shift motor and varify the shaft moves when changing to 4x4.
Assuming you are not defauling to defrost then the vacuum side should be fine.
10-4, I'll have to check that tomorrow. I didn't mention in the first post that the hubs aren't moving in 4 hi or low. Can it fail before it moves them? Not even a slight variation in A/C output. Stays solidly out of the dash vents.
I wasn't certain either so I posted the pic. Wishful thinking I guess but I wanted it to be that thing (vacume actuator) looking more like the shift motor. Xfer case was serviced last year (2014)
So maybe blow off the GEM DTC for now, the switch seems to make the dash light work so at least part of that is working correctly. The shift motor makes a "motor" sound for a second or a little less and then a thunk. Sound like it hit home or at least ran into something. I guess for my next step I'll pull it off and verify it going full travel.
So maybe blow off the GEM DTC for now, the switch seems to make the dash light work so at least part of that is working correctly. The shift motor makes a "motor" sound for a second or a little less and the a thunk. Sound like it hit home or at least ran into something. I guess for my next step I'll pull it off and verify it going full travel.
Can you lock the hubs manually? When mine are in auto once in awhile they wont lock but the 4X4 always works when they are in manual.
Mine quit working last winter,light on dash came on and everything but it was a no go when I was stuck in the middle of the road,manually locked the hubs in and I was good to go.come to find out the vacuum pump under the hood was getting weak and not pulling enough vacuum.
I actually noticed this a few days ago. My wheels have a center cap that requires an Allen key to remove and I didn't have one that would work so I couldn't try manually locking them when I was stuck. Later I did pull the caps and the hub locks aren't moving with the switch. I could move them to manual by hand but I didn't take it out and see if I had 4wd when I did it. I'll check that tomorrow also. As I posted above they did seem kinda hard to turn but I didn't have the truck running or the switch in 4x4. Maybe they are easier to turn like that.
I've only owned a couple of 4wd trucks and was lucky to not have much trouble with them so I'm not very experienced on this subject.
Iirc the 4x4 indicator is only illuminated when the shift motor has physically moved, same as low range. This is not simply the output from the dash switch or relay. I would look close at your hub hubs and vacuum system.
Jack the wheel up, apply vacuum to the hose leading to the hub right at the connector. Its sitting at the frame rail in the wheel well, just pull it off the plastic piece (first break) right where the well cover meets the frame. Pull a good vacuum and then spin the wheel by hand, it should go into 4x4 with not much movement.... if the inner axle seal, both o-rings, the hub itself and the vacuum tubing can hold vacuum.
My vacuum tool has a gauge on it, couldn't really pull anything, it just sat at zero when I started trouble shooting.
1) bad rubber tubing leading to the hub.
2) bad hub o-ring. Get at Advance, Dorman brand, black colored, goes around the hub.
3) wheel bearing o-ring, yellow colored, goes around the wheel bearing.
4) axle seal, big fat seal you drive into the knuckle using a axle seal tool or maybe PVC pipe.
And from what your saying earlier (A/C doesn't shift to the defrost), you probably have something in the hub bad. Axle seal is typically worn out from all the one's I've help fix. Seal runs $70, o-rings are about $10 each and a small 2' piece of tubing from the parts store about $4.
If its the axle seal, you can make a tool or get the one made by OTC for around $60. I bought the tool from Advance and all the parts as well, did it on-line and used the code TRT30 and saved 30%, had them shipped to the house.
If it doesn't click when you spin the wheel after applying vacuum to the hub, time to replace something.
using the vacuum pump on the truck it's pulsed. Unplug the vacuum tubing going to the hub, connect your vacuum devise to the tubing makes it work and won't pulse the hub, just a good vacuum test to see if it will work or help you find a vacuum leak. Ideally, you want it to hold the vacuum, then spin the wheel and it should lock it in, if all the seals and o-rings are good.
Seems to be the season for 4x4 and all these hub questions come up again. When I get back from this Bahrain trip (work gets in the way), I'll do a video or picture thread of trouble shooting and the fix for ESOF hubs.
