4wd/4Lo flashing light brought me here

Been reading/doing the mechanical fixes posted on the various ADD/Transfer actuator posts with no change. Not knowledgeable about the electronic side of things. Starting to double guess my mechanical abilities at this point then found the posts about the ground point EE and did a few quick checks on that (Do the flashing lights go away & 4WD works as should when ODB scanner attached) Success!! Now I'm going to have to try to educate myself with the electronic tracing, since cleaning up that EE ground point didn't help. Also note - had a bunch of emission codes come up (P043E, P043F,P2401,P2402 AND P2419) as well that would not clear and now when trying to read codes the ODB scanner = fail for some reason but the 4WD now works with scanner plugged in. I'm so excited for some progress. Thanks to this forum.

 

I'm assuming your truck is a 2nd gen (you didn't post your year model).

We've been here before, check out Posts 236, 237, 254, 257, 259, 272, 274, 275, & 278 of my thread. I explained why plugging in a scan tool will temporarily "fix" a ground issue on that ground tree and why a bad ground there will also cause EVAP codes although we have not found where that ground breaks as of yet so if you can find it that would be great.

 

yeh its a 2008 trd off road 6 cylinder manual. It is at the local garage to get some other issues fixed (Power steering Pressure line started leaking and have a ripped driver's side CV boot). Told mechanic that I was thinking that the grd may be causing the 4WD & emission problems. He said he would also check on the speed sensors while he's working on the other stuff. Got pretty messy under there. Before the truck left here though -I just found the grd post topic this morning & started down that path & believe I was making progress. When I get the truck back I'm going to continue. I do have a question though - I under stand the ground sharing on the ODB scanner -- since my scanner no longer will read my codes and report back (it fails) - could that mean that my bad wire is on PE pin 7(Data link connector)? or is that just another side affect of a bad ground?

 

It's possible but since you said things work with the scanner plugged in that tells me the other ground is good at the OBD port so the ground is likely not the issue causing a no com.
Did you make sure your scanner plug has no bent/broken pins?

 

scanner reads in our other vehicle so the scanner itself is good. Haven't checked the tacoma port yet. Will when i get it back