Code help(fixed maybe)

[Redfisher1974]

Hello my 2017 outdoorsman 3.6 has the serv 4wd light coming on randomly most days. When its on I can’t use 4wd but cruise control still works. Usually clears after 30 seconds.
Anyway i got a decent scanner and it came up with this code under ABS, it also googled it and after a quick read i think maybe a open or short in harnesses to ABS module? Any help would be great!

 

[csuder99]

Does your location use road salt in the winter ? Could be "green crusties" in a connector.

 

[mtofell]

I'm no mechanic by any stretch but have read about wheel-sensor issues with ABS related codes.

 

[Redfisher1974]

Does your location use road salt in the winter ? Could be "green crusties" in a connector.

Yes im in Canada, lots of salt! Im gonna try cleaning up the connection at ABS module.

 

[Redfisher1974]

I'm no mechanic by any stretch but have read about wheel-sensor issues with ABS related codes.

My first thought was speed sensors, I’ve ran my scanner on all 4 sensors in graph mode and all are even with no spikes while moving.

 

[Redfisher1974]

Well maybe i fixed it!!! (Knock on wood)

Pulled ABS control module harness and found the green fuzzies on bottom pins. Cleaned everything up ( forgot to disconnect battery) so when I restarted truck i got 4 new codes (think just phantom codes from unplugging ABS without disconnecting battery)
So I disconnected battery for a while and after rehooking up battery and starting only had one code which i cleared with my topdon scanner.
Went for a rip and no codes so far, scanned after rip and looks clear.
We shall see!

 

[Redfisher1974]

One question, i was playing with scanner doing live feeds and such on all abs components and noticed this with brake pedal switch, I thought it would be 0v at rest and 12v at pressed but i get this? (See pics)

 

[Redfisher1974]

3 days no codes!

 

[csuder99]

Glad you found the problem.

Modern vehicles don't have a simple switch anymore for the brake pedal. A typical automotive position sensor operates in the 0-5V range, in case of the brake pedal they actually use two of them for redundancy.

 

[Redfisher1974]

Glad you found the problem.

Modern vehicles don't have a simple switch anymore for the brake pedal. A typical automotive position sensor operates in the 0-5V range, in case of the brake pedal they actually use two of them for redundancy.

Aww that makes sense! Thank u kind sir.

 

[Redfisher1974]

Arrrrrgh…
Well the serv 4wd light is back!
Seems like every time i think I’ve fixed this it’s good for a week or two then comes back! But when it comes back its a different problem.. Now the serv 4wd light comes on with key in run position before you even start it. Stays on until you reverse out drive way then it shuts off when in drive for about 30 seconds.
No U-codes this time, ( my scanner does not see TCCM codes)
I can graph my abs sensor’s and they look good, im starting to think it’s software in TCCM unit.
Almost like upon turning key it sends a signal and it doesn’t hear back so it lights serv 4wd then when driving in forward it re sends signal and the TCCM wakes up and clears light.. I dunno but wish something would just break so i know what it is.