Hello all....I posted this in the Excursion forum a few weeks ago and haven't gotten any responses yet. I was hoping this forum might be a better place to get help.
I have a 2000 Excursion 7.3 4x4 Limited with 225K on the clock. It runs strong and I don't notice any issues. I recently picked up a OBDLink LX and have Forscan on my laptop. I was getting a flashing OD light for a bit after I drove thru the snow the other night and it happened exactly when I went back into 2wd. I will post my codes and list the work I have done. I would appreciate some assistance in interpretation with these as some make no sense to me. I was not expecting this many codes. There is NO Check Engine Light on at the present moment...never has been.

DTC B1681 - No transceiver signal received from the module/no transceiver detected. (No clue what this even means)
DTC P0475 - Exhaust pressure control valve malfunction (might be from the EBPV delete?)
DTC P0720 - OSS sensor circuit fault (No clue what this means)
DTC P1211 - Injector Control Pressure Higher/Lower Than Desired (engine running)
DTC P1316 - Injector Driver Module Codes Detected (No clue again)
DTC P0238 - Turbo/Super Charger Boost Sensor A Circuit High (brand new MAP sensor)
DTC P0478 - Exhaust pressure control valve malfunction (also from the EBPV delete?)
DTC P0722 - Output Shaft Speed Sensor No Signal (transmission related?)
DTC P0541 - Manifold Intake Air Heater Circuit Low (this has been deleted)
DTC B1203 - Fuel sender circuit short to battery (no clue here)
DTC B1428 - Safety belt lamp circuit failure (I think this is from not having a bulb....needed it for 4x4 which was burned out)
DTC P1876 - Transfer Case 2-Wheel Drive Solenoid Circuit Open Or Short To Ground (I suspect this is causing the OD light to flash)
DTC P1865 - Transmission Transfer Case Contact Plate Power Short to Ground (I suspect this is also causing the OD light to flash)

What I have done to the vehicle so far....

Suspension/etc..: X codes in front and modded B codes in back, Bilstein 5100 all around and steering stabilizer, cleaned pickup filters in tank, new Bosch fuel pump, Edge Monitoring system with air pressure attachment (boost)/EGT monitor/Transtemp, all new fluids, upgraded headlights to clear lenses and all other bulbs to LED, Pioneer DVD player, LED relay.
Engine: S&B Intake with MBRP 4" exhaust, new MAP sensor, 203 degree thermostat, Dieselsite coolant filter, new water pump, RiffRaff boots and plenum inserts, International bellowed up pipes, turbo rebuilt with 4 way thrust washer and WickedWheel2, EBPV pedestal delete, new EBPV sensor and tube, new Bosch fuel filter, Dieselsite mechanical wastegate controller, new Degas bottle and cap, new GPRM, new IPR, has a TS chip but I am unsure of the tunes (guessing stock).
Transmission: 6.0 trans cooler, Dieselsite trans filter, John Woods valve body, bypass removal kit (per his recommendation), trans only gets up to 230F now...not sure if that is too low or not, I also recently replaced the 4x4 vacuum hoses that connect to the frame and hub.

Any thoughts on these errors? I hope I have provided enough info here.....again, I was not expecting this many with it running so strong.

 

It means there is an electrical circuit problem with the Output Speed Sensor on the trans. I think on the 4x4 Excursion this sensor is on the output of the transfer case, I don't remember for sure. It could be on the trans. This code will make the OD light flash.

This says that due to the previously mentioned electrical fault the PCM doesn't see a signal from the OSS. That's because there is an electrical problem. Fix the bad wire and/or sensor and this code will go away. This code will make the OD light flash.

I'm not a transfer case expert, but I think these will flash the OD light, too.

I strongly disagree with this, but to each his own.

That is at the upper end of normal. You don't want to run that hot for more than a half hour at a time without cooling it down.

 

Thanks for the response Mark!
I checked with Ford and they seemed to think it was the OSS that was causing all of these codes to show up. Unfortunately for me, there aren't any around so I will have to wait until Tuesday to pick one up and find out. They mentioned it was at the back of the trans on the very top. I will have to remove the skid plates to get my head up there and verify....no room for my arm either.

On the transmission temp....I meant to put down that it only gets to 130 degrees....running for 4hrs at 70mph. I have not towed with it yet.
I did some searching and found your posts on removing the bypass. I still have mine in my garage so I can put it back in if I should. I used to have the stock trans cooler and a Hayden cooler added to it. I pulled a pop up camper and got to 235 and 240 going up a mountain pass. I figured they just weren't enough for towing so when I swapped out the trans cooler for the 26 row version, I decided to change the valve body. JW recommended it and he knows more than I do, so I did it.
If I put that bypass back on, should I replace the bolts (one or both had a check ball and springs in them if I recall) or just re-use them? I have them in there now so it would be an easy swap.
Thanks for your input on this....
PS: I have been driving around town and no OD light.....makes me wonder if its actually that transfer case solenoid causing it. There are two plugs on the transfer case...one in front, one in back. I am going to check my Haynes book to see which is which.

 

At the very least the spring needs to be replaced. Summit sells a rebuild kit for the bypass that's pretty cheap.

 

Thanks Mark...ordering one from Sonnax.

Is the trans temp of 130 degrees OK, or should I worry about that being too low?
I have seen a check valve that helps with this, but with the DieselSite filter inline, I wonder if that would be too restrictive on flow.

 

That is a bit low. A cheaper way to bring the temps up on cold weather is to put a piece of cardboard over the cooler in cold weather.