No 4WD in 01 Taco. Troubleshooting Tips?

[SEREvince]

My 4WD stopped working. No indicator light, no 4WD, nothing. It's a 01 Tacoma dcab with ADD. I have the shifter not the push button version. I've never had any issues before and used it with no problems a week before it went out.

Could you guys help me out with any trouble shooting ideas? I checked the fuses the day it happened on the trail and they all look good. The shifter feels normal when moved, but nothing happens.

Thanks!


Vince

 

[Applejack]

Well since you have a lever you can eliminate a transfer case issue, based on the fact that you said it shifts in normally. So the best thing to do is crawl under unplug the wiring harness and use a test light to see if power is being sent through the wires. If you have power on the t-case end, trace the wires up to the diff, looking for any breaks in the wires.

 

[mauricio_28]

If it has ABS, check that the ABS sensor cables are intact.

 

[pray4surf]

ADD correct?

If so, when you shift in/out of 4WD, are you hearing the relay in the passenger footwell 'click'? If not, start by checking the wiring connections on the switch on the transfer case and at the relay.

Next, crawl under the truck and locate the two vacuum lines that actuate the front diff. With the truck running, pull off the vacuum lines one at a time and listen/feel for vacuum as someone else shifts into/out of 4WD.

Check out this TTORA post of mine for a diagram of the ADD system
http://www.ttora.com/forum/showpost.php?p=1511927&postcount=9

If you do not have vacuum when shifting into 4WD, check the vacuum line and also the electrical connection for the VSV4 solenoid.

Here is the FSM page on testing the ADD Control System
http://www.ncttora.com/fsm/2003/Repair_Manual/03tacoma/sa/acsy14wd/insp.pdf

Good luck.

Rick

 

[RHINO]

you sure its not a pre runner?

j/k i dont get the actuator thing in the front diff, i would rather have hubs.

 

[SEREvince]

ADD correct?

If so, when you shift in/out of 4WD, are you hearing the relay in the passenger footwell 'click'? If not, start by checking the wiring connections on the switch on the transfer case and at the relay.

Next, crawl under the truck and locate the two vacuum lines that actuate the front diff. With the truck running, pull off the vacuum lines one at a time and listen/feel for vacuum as someone else shifts into/out of 4WD.

Check out this TTORA post of mine for a diagram of the ADD system
http://www.ttora.com/forum/showpost.php?p=1511927&postcount=9

If you do not have vacuum when shifting into 4WD, check the vacuum line and also the electrical connection for the VSV4 solenoid.

Here is the FSM page on testing the ADD Control System
http://www.ncttora.com/fsm/2003/Repair_Manual/03tacoma/sa/acsy14wd/insp.pdf

Good luck.

Rick

Yes ADD, no ABS.

This look like exactly what I needed. I'll give it a shot, hopefully it's something simple, but I have I feeling it's going to be something impossible to get at and expensive to replace.

Thank you!