Reprogramming a used ECM for 2nd Gen Tacoma (2007)???

I'd bet one or more of the 4wd limit switches is missing a ground too, really have to check the limit switch voltages to see what's going on but that would be ny suspicion.

https://www.tacomaworld.com/threads/4wd-system-operation-help-thread.742420/page-12

 

Thanks - I'm pretty new at this so just wanted to clarify after reading the above linked thread. Where exactly am I checking the limit switches? Is that done on the main ECU or on the 4WD ECU under the dash or is there somewhere else I need to perform these checks. I assume I can do this with a multimeter and backprobe? Apologies for all the questions Any other guidance for a rookie would be appreciated!

 

You want to check the voltages at the 4wd ECU (see the thread I linked for it's exact location), yes you can use a multimeter set to Volts DC and meter ground connected to a known good ground.
If you have a printer print the voltage chart out that I have there, write your results on it, and post a picture here.

 

So I think I did it correctly but only did the test with the 4WD control know in 2WD.
Some strange readings on a few PINS (jumping around like crazy) so not sure if operator error or what

 

I'm at work right now but at a glance looks like a bad ground to the actuators (none of the voltages are at 0v), I have links in post 2 of my 4wd thread to someone with that issue and the trsting we did to find it. (Bad ground on EE causing flashing 4wd lights, no cruise, & EVAP codes).
Essentially the next step is to check the ground voltages on the corresponding pins at the JB No2 (see the posts I described above).

 

I just had a chance to read the post you mentioned and I went after PIN 18 on JB2 and I was showing voltage of 11.4 V.
Not sure what that means???

I also looked at ground EE on the back of the head and I think I was checking it properly. Multi meter set to direct current. Black lead in the COMMs port of MM and the red lead checking the ground point. I checked a few around the engine bay and was getting 0.2, when I checked EE I was getting 0 or 0.1. I think this was the issue with my non-start issue before and my mechanic looks to have made a new ground to the chassis? See photos below of EE

 

Here are the photos of the new ground that was made by my mechanic to solve my no start issue. Note the 4Lo flashing and no 4WD engagement was already an issue prior to the non start.

 

Have you given those wires all the tug test, they all look pretty crusty there at EE.

 

Also if your in the salt belt (which it looks like you are) that non-sealed butt splice isn't gona last more than a year or so before it corrodes enough to have a bad connection again.

 

Thanks. I have not given those wires the tug test but will do so tomorrow. Just so I understand are they going to the ground point too or to something else on the block? I thought the ground wire was the one (white/black) running to the single point on the back of the head (where blue collar is).
Yes we are in Ottawa, ON Canada home of way too much salt on the roads.
The butt splice you are referring to is that the new one I mentioned (yellow wire with blue end)?

 

There are multiple wires at EE, they all ground different circuits.

Any wire/splice/connection that isn't sealed or coated with a corrosion inhibitor will corrode very quickly when exposed to salt spray, that's why it's always best to either use a crimp & seal splice or solder and heat-shrink the connection using heat shrink with adhesive to give it the best protection against corrosion.

In an area like where I'm at where there is no salt/corrosive agents put on the roads one can "get away with" using non-sealed splices on exterior wiring but it's still not ideal to do so as they still can eventually corrode.

 

Yup, I cringed when I saw that. If it isn't an issue yet, it will be.

 

I got a new 4x4 ecu re-flashed and tuned for my supercharger with hp tuners, but my 4x4 light blinks. Do I need to pair the 4x4 computer with this new flashed ECU?

 

The 4wd ECU is totally separate from the PCM, if the 4wd light is flashing then there is a problem with the system.
See the thread below for tips on diagnosing it.
https://www.tacomaworld.com/threads/4wd-system-operation-help-thread.742420/

 

Forgot to post an update:
Turned out to be another bad ground on the front actuators (?). Mechanic made 2 new grounds and solved the problem. Engages in 4WD perfectly now. Fingers crossed for no more electrical issues.