4wd System Operation & Help Thread

definitely correct pin and here is a nice picture of yellow L4 going to transfer case

 

And the transfer case isn't physically in Low?


Also I fixed my screwup, I didn't realize I labeled that incorrectly, guess I wan't paying attention

 

its in 2H

 

So just to make sure I'm understanding, when you ground PA Pin 18 (White/Black) the 4wd system works but you have a VSC light or the system is still inoperative?

 

system is not operational in any condition
when I ground pin 18 on PA and unplug L4 from transfer case there is no lights on dashboard
with above when switched to 4H light just blinks and its not engaging
transfer case actuator is tested to be in 2H, there is continuity between pin 4 and 5
driveshaft going to the front axle is spinning freely also front wheels are spinning freely when jacked up

 

I think fix the ground since we know that's bad for sure then redo the voltage checks for 2H and 4H and see what's still out of range.

 

Is there a post showing the location and a diagram of the 4wd electrical connectors behind the glove box for a 3rd gen taco? I am trying to troubleshoot my 4wd issues with my 2017 Tacoma. Replaced actuator, tcase, took it to a shop. No luck. Light is flashing and won’t stop even though the truck is in 4wd.

 

There is a thread for 3rd gens but the 3rd gen 4wd system can talk to a scan tool so if you have access to one that can read all systems I'd be using that to see codes and the status of the limit switches rather than poking wires.

3rd gen thread can be found here.
https://www.tacomaworld.com/threads/4wd-actuator-troubleshooting-transfer-case-and-add.578262/

 

I have a 2006 tacoma 4wd with the 4wd light flashing. when turning it to 4h the transfer case shifts into 4h. then the 4wd light starts immediately flashing. I've replaced the add actuator and the trans case shift motor, no change. If you turn it back to 2h it does not move. light keeps flashing.

 

Same procedure applies, start with checking your limit switch voltages in 2H and 4H as outlined in the first post of this thread and posting your results.

 

ok tl1 2h expected ov act-.006 4h expected 12v-12.15
tl2-12v-12v 0v-12.16v *
tl3 12v-12v 12v-12.17
4wd 12v-11.8v 0v-.01v
l4-12v-11.8 12v-11.88
dl1-0v-.002 12v-.002v *
dl2-12v-11.69v 0v-12v *
add-12v-11.38v 0v-11.48 *
2-4-0v-.002v .05-.07v--.673v
lo-12v-11.99v .05-.07v--.671v
I see the 4 that are out of range. what do I do now?

 

I think verifying circuit integrity of TL2 should be the next step.
Unplug the Transfer Case Actuator and jump Pin 4 (White/Black) (Ground) to Pin 6 (Blue/White) (TL2) with a small paperclip or other suitable jumper that won't spread the terminals then verify TL2 goes to 0v at the 4wd ECU.

 

t2 did go to 0v and 4wd light on and not flashing 4wd lo

 

So we have an issue in the Transfer Case Actuator, either it's not timed correctly or an issue with the contacts/plate.

 

I'll pull it apart and check. Thank you very much for your help. I'll let you know what happens

 

ok, if I time it in 2h, cranh it up no lights on. Turn it to 4h it engages and starts flashing. If I time it in 4h and crank it up it shows to be in 4wd. I can shift it into 4l and it engages. Turn it back to 4h,all good. Turn it to 2h and it starts flashing and tc remains in 4h.

 

Did you check the actuator timing, contact plate, and contacts?

 

all the contacts look good,its like it only turns half way back to 2h then starts flashing

 

Do you have pics of the contacts?

Do you have your old actuator?

 

I have the old actuator and its contacts are definately toast! I have compared the two and they are identical. I don't have any pics of the new contacts but they dont have hardly a scratch on them