Hey guys I just bought a 2007 F350 CCSB 6.0 auto 4x4 with 113k miles on it, it does have the 5th wheel gooseneck trailer hitch in the bed...anyway of course when I looked at the rig everything checked out and now I am getting a U1900 for ABS CAN communication...I should add that the ABS Light itself is not on, just the CEL...I have a feeling it has something to do with the wiring that the PO maybe had done to wire for his 5th wheel hitch?...I checked all the ABS related fuses in both fuse boxes and theyre all fine...
While reading another post on the possibility of the brake pedal position switch up on the pedal itself being bad, someone mentioned that the wiring may be jacked up due someone adding wiring in for the 5th wheel hitch...I also checked the brake pressure switch on the nose of the master cylinder and that looked clean altho I didnt test it...should I just replace these since theyre pretty cheap or is there something I should look for in the wiring underneath the dash? Oh and of course my cruise control isnt working either...likely because of this ABS wiring issue...any help is appreciated....after this I can figure out whats causing my underboost! yikes

Steve

 

anyone have any idea where to start looking?

 

What are you using to check codes? Using something like Forscan can reveal a more specific code to the problem.
A communication failure could be the plugs on the top of the cluster, bad cluster, or a bad Integrated Trailer brake module.
Using Forscan you can monitor the ITBC to see the outputs.

Forscan lite screenshot

 

Thanks for the help. I initally had it checked at Autozone they used a regular Scanguage II but then my bud who is very savvy with 6.0s used his Snap On Solus Ultra scanner to read the codes again...its apparently a 3,500$ scanner its all touchscreen and it said u1900 ABS CAN Bus Malfunction I dont think it was much more specific than that...He said to check all the fuses and relays and any switches or brake related sensors if not than it could be a bad ABS module but I dont think its the module I think the previous owner wired up something for his trailer and messed with the wiring...he also had strobe lights too so I am thinking its something eletrical maybe he took a fuse out and put it in somewhere else or did something...I should add I do have the ITBC under the radio and that seems to light up when I touch it and adjust the gain....do you know where to look/what to test specifically for that ITBC? Thanks!

Steve

 

I'd start with like I said above. Have your buddy check all the inputs and outputs of the ITBC.
Usually that code alone means a connection was intermittently lost or shorted. If you have a boogered up harness repair that first. If this code only pops up after you plug in the trailer and not any other time that may be an indicator. I think if it was the ABS or ITBC module(s) you'd have other codes.
Do you have ANY other issues like speedo reading funny or anything?

 

Thanks...I havent towed a trailer yet so I dont know if it happens then...which harness are you referring to when you said to repair that first?
I do have another code for underboost but thats un-related...my cruise control is not working, however the radio/climate controls on the right side of the steering wheel are working fine...just the left side CC arent...UGH!
what do you think about checking the brake pedal switch or ABS pressure switch on the master cylinder? I wish it was something simple like a fuse or relay

 

Cruise control not working? Are you sure it's the wheel? CC uses some of the same inputs as the ABS and ITBC modules.
And yes, check the switches. Like I said from the start this can be done with Forscan or your buddies Solus scanner. I showed you and example of the inputs and output PIDS in the pic above to show you what ones to check.

 

Thanks again...I am not sure its the 5th wheel I dont know what it is honestly...but yes my Cruise is NOT working...I will have my buddy use his Solus again and get those readings done...I guess I will just go ahead and change those 2 switches those are relatively cheap....do you happen to know the part # for the brake pedal switch? I can't find the switch itself just the wiring harness...in the meantime im gonna download Forscan! Thanks!

 

Use the Forscan to test the switches. Don't just throw parts at it. It may just be a bad connection like the plugs on the instrument cluster or something. Test first to verify that the switches are feeding the modules.

 

I am certainly not just throwing parts at it I am going to test it today I just got my OBDLink MX WiFi that I am going to use Forscan with....thanks for the help, now I just gotta hope that I can run those tests that you did to test those switches.....

 

welp I used Forscan it says Code B1483 Brake On/Off Switch Circuit Failure....so I ordered the 15$ brake pedal switch I already have a cruise control/brake pressure switch that goes on the master cylinder I will put on...I also couldnt find all the readings you had on your dash, I could only find BPA which was OFF and (2) BOO which 1 would turn on when I pressed the brake and another did not....even hit the E brake and got nothing....do I need to upgrade my Forscan? Thanks

 

There is a test for the ITBC if I remember right. Just poke around and you should find it. It's hard for me to remember exactly how to get there or I would walk you through it.
Sounds like you're on the right track.

 

Thanks, I did find it and they all checked out OK...even all 3 wheel sensors were OK...however, ABS is listed *** OFF on the ABSSTAT, as well as BPA (Brake Pressure Applie Switch)...when I press the brake pedal I do get input on one of the BOO_TBC inputs..the ABS, AWD and PCM MSG all say no fault...so I don't know what the heck to do! I looked for something with cruise control and couldnt find anything ...I am guessing that it could be either switch on the master cylinder or the brake pedal itself, at least I hope it is

 

Hey 87- another update...after I installed both the brake pedal switch and brake pressure/CruiseControl switch on master cylinder yesterday I cleared my engine codes and drove for about 90 miles...the check engine light just came on again about 5 miles ago, but this time nothing for the ABS! So I drove the truck while running Forscan and the BOO(brake on/off) 1 switch works however the BOO 2 switch still doesnt go on, regardless if I slam the brakes...the good news is that the BPA(brake pressure applied) switch will turn ON if I press the brakes hard enough, whereas before I had nothing from that reading....the ABSSTAT is still off, but when I press the brakes the BOO ABS switch does switch to ON, whereas I dont think it did turn on before either....

so now I am left with that 2nd BOO switch not changing as well as ABSSTAT listed as off...I wonder if I have to actually brake to the point my ABS engages for those 2 to even show up? how do you reccomend for me checking to see if the ABS works?

Also, the other annoying thing is that my CC still does not work...
so let me know what to do from here as far as running a network test as well as if you think it could be the brake pressure transducer, although I dont see why my CC wouldnt be working if that was bad....

at least theyres no more engine codes for this! now if I could just get that damn CC to work....maybe its the clock spring?

Thanks!

 

I haven't had time to use Forscan on the laptop but I did plug in this afternoon and checked mine with Forscan lite. In all modules the BO/O switch turns from off to on immediately pressing the brake pedal.
Are you using the laptop version?
There's got to be a connection with the Cruise Control not working too.
. There's a test procedure for checking cruise buttons if I remember right. I'll try to find it or maybe Sean can post the PDF.