2011 Tacoma 4X4

Hello
Looking for help and advice
I have a 2011 Tacoma crew cab 4x4 not a TRD
My 4x4 low light flashes and it disables the 4WD and cruise control
It started after using 4 low to move a ton of pellets
It went out of 4WD ok but shortly after the light started flashing
I changed the 4x4 solenoid on the front differential and still the same
Now here’s the kicker
If I leave my code reader plugged in before I start it the light doesn’t come on and everything works fine but soon as I unplug it the light comes right back on
I think maybe there’s a stored fault code ?
I unhooked the battery for days and it still does the same thing
I’ve reached my limit
Any help ???

 

It sounds like a ground issue.
Most scanners jump (bridge) the grounds at the OBD connector.
Let me over look some diagrams. I bet we can resolve this.

 

I appreciate any help

 

Do you have a voltage meter?
A few simple test should narrow down where to look.

 

I have a volt meter but to be 100% honest my knowledge of diagnosing wiring issues isn’t the best
My wheelhouse is more mechanical but I’ll try anything

 

All you need to do is check voltages.
Set the meter to 12v (or 20v) DC.
Take the red lead on the meter a probe pin 16.
And the black lead and probe pin 5.
See if you have 12v

You can also do the same thing for pins 16 and pin 4.

 

It would also help to know what the stored fault code is.

 

Thank you
I will do this tomorrow
My cheap code reader doesn’t show any codes

 

To help understand “why” it works with the scanner hooked up.
I add the following diagram.

When you plug the scanner in, it “connects” pins 4 and 5.
So it ties those two grounds together. If one ground is bad, then the other one will “take over” when the scanner is plugged up.

The 4WD system uses the EE ground. Which is the same ground as pin 5 on the DLC.
Which is why I want you to check that pin.

 

That was great TN! That was so easy to understand like that

 

Yeah, truth is, you can still have show 12v on a bad ground.
But we’ll cross that bridge when we get there.
Showing voltage and carry a load are 2 different things

But I don’t want to make things confusing for OP.
Let’s take 1 step at a time. I’m bad for throwing too much info at people at once.
Sometimes, that makes it more confusing.

 

We have been here before although so far no one has found where the wire breaks and instead did the bypass.

From my 4wd help thread:
https://www.tacomaworld.com/threads/4wd-system-operation-help-thread.742420/

Bad ground on EE causing flashing 4wd lights, no cruise, & EVAP codes (See Posts 236, 237, 254, 257, 259, 272, 274, 275, & 278

 

Has anyone ever reported an evap code at the same time?
The evap pump is only grounded to EE as I can tell?
And it comes out at the same pin to EE.
I don’t recall anyone having an EVAP.

just brain storming here.
trying to “narrow” down the “break”.

 

Yes along with cruise inop, see the posts I linked to above.

 

How did I miss that…..you literally said it in the post before mine.
I think I need to get some sleep. I’m missing whole parts of post at this point.

 

I miss read the pin 5 voltage
They are both over 12volts

I put a jumper between 4 and 5 and the light stays out and everything works

 

If you had voltage on both 4 & 5 that mean the ground is likely bad on the 4WD ECU side.
Both the DLC and 4WD ECU exit on pin PA-18, so I wouldn’t suspect a bad wire to EE.
We could narrow it down by testing ground at the 4WD actuators, 4WD ECU, or the junction connector behind the glove box.

I would unplug the Junction Box connector behind the glove box and look for corrosion.
Unplug connector PA (one on top)

 

I don't have time to lay it out at the moment but if you follow the posts I linked to above it should get you there, if not I'll have time to get into details later tonight.

 

OP, did you look over the link Dm93 posted?
We are happy to help. But reading the posts linked would “help us” help you.
It’s a lot of work to walk someone through step by step.
Reading the posts linked would help you get more familiar with the components we’ll be needing you to test.