UPDATE: Fixed, it was a combination of the PVH Solenoid, GEM module, and the transfer case motor. By swapping in all the original ones I was able to determine that all three of these infact need to function for ESOF to work, back in business baby!


Good afternoon gentlemen.

I have a '02 F350 CCLWB SRW 7.3 4x4 Lariat.
She's got 345,000 on her and I went with my father to buy it in '03. It towed a camper around the southe east when we used to race Motocross, and then after drove the family and dad to work till 2020 when I purchased it.




The truck is equipped with the oh so amazing ESOF on the dash with Auto hubs. I never had functional 4x4 via the switch. So I've just recently started to diagnose and try to fix this.

​​​​​​I have access to AllData as well as a Autel Scan tool for when I reference anything.

I couldn't communicate with the factory GEM (4x4) module under the dash behind the glove compartment, the windshield previously leaked and I had to replace it so I'm assuming this is what caused the issue.

I found one with a matching part number on eBay and replaced the old one. Now, I can communicate with the module and read codes, + after the truck starts up, for a brief moment the 4x4 low and 4x4 high lights illuminate, that previously did not occur.

I found two codes in the module section on my scan tool, and referred to AllData for further information.
DTC P1834
DTC P1876

I followed the instructions and found my "PVH" as AllData calls it or "4WD Actuator Solenoid" as AutoZone called it to be faulty. I was able to confirm the harness between the module and the PVH was good, as it Ohm'd out perfect with no resistance. However the solenoid itself did not OHM out at all and displayed an Open loop. I hated the new one and it was between 0.09 and 0.04, and installed it. This has fixed my two codes, DTC P1834 &DTC P1876.

However still now, with the engine on and in neutral, foot on brake I still cannot get the transfer case to switch with the ESOF (4x4 switch) on the dash. I did command the dash lights and both high and low 4x4 illuminates fine.

The truck now only throws ,
In the Overhead Trip Module
B2148 PWM(Pulse-with modulation status) Input Circuit Failure.
P0500 VSS (Vehicle speed sensor) Circuit fault

This overhead console hasn't worked for 10 years. Clearing them makes the stay away for quite a while.

In the HEC (Hybrid Electric Cluster) module
C1284 Oil pressure switch failure
B1352 ignition key in circuit fault
and again,
B1352 ignition key in circuit fault.

I however have no CEL on at anytime, truck starts and stops fine etc.

What's the deal? What else can I diagnose from this point?

Thanks.

 

If you turn the front locking hubs from AUTOMATIC to LOCK, does your 4x4 system work?

 

No change, besides locking the hubs to the axle shafts.
Transfer case still in 2WD, switch does not acuate the transfer case, driveshaft still spins freely

 

The most common cause of this is the shift motor failure.

 

I'm about to parts slap a new one on as soon as I get back home lol. Parts shotgun is firing on full auto today lol

 

OK. Load the parts cannon and let us know how it goes.

 

That did it, I swapped in all the old parts after to confirm and all three failed at some point, PVH, GEM, and Transfer Case Motor lol.

Thankfully though this wasn't a wiring issue.

 

Sheesh, a three-fer

 

I lied. It worked fine all day yesterday, this morning went to test it again, KOEO, it tried too, then failed. Now it's not working again, with a new code, Code P1865 Transmission Transfer Case Contact Plate Power Short To Ground.

Got another new TCase motor, gonna parts slap it and see if maybe this cheap Dorman one failed.

 

New TCase motor and it's back up and running, found water in a connector and reassembled with dielectric grease this time on the new unit