Secondary Air pump stuck on

My Tacoma is no longer my primary vehicle, so it can sit for a few days at a time. Recently, came back to find it dead. Hooking it up to a starting battery, I managed to get it started, but as soon as I hook power up, the secondary air pump starts running.
It (or issues related with it) is drawing enough power that when I disconnected the battery, my engine died.

I've browsed a bit, found issues with the air pump system, but none of them match my problem.
Right now, I'm suspecting a short and/or a bad relay, but haven't had much luck finding diagrams, including/especially wiring. It took me a bit just to find that the pump was the "secondary air pump".

Does anybody have a clue as to what might have happened, and what the fix would be? My brother borrowed the truck for a couple weeks while I fixed his van. Didn't see any issues when he returned it.

 

What year and what engine?

 

Would help to know the year and engine of your truck but it would seem you have an issue with the Air Injection Control Driver module.

 

I was putting together more information, totally forgot:
2008, 2.7L engine.
This happens when I apply power: IE connect the battery back up. The truck does NOT need to be turned on.
I also finally got the connector out of the air pump, leading to more information:
The ABS pump module is also running. It was quieter, so I couldn't hear it, with the other one hooked up.

Edit: To be clear, this is just hooking the battery up, no key in the ignition, no nothing.
Thank you for your help.
@Dm93, I'm going through your links right now.

 

That's interesting, would seem something must have happened to cause this. Reverse connecting the battery, jump-start, lightning strike, etc.
Modules typically don't fail in that manner and almost never do you have 2 fail at the exact same time.

 

That's why I'm scratching my head. I never get the easy simple problems. (Well, I do, but I'm not forced to ask questions online about them.)

I'm actually wondering if there's a short somewhere between a constant power positive wire (or such) and something that should be switched. I mean, those modules shouldn't even be getting power without the switch being turned on, should they?

Possibly rodent related, though all the wiring I can see looks fine.

Thank you for the wiring diagrams.

 

It would be hard for it to be a short. As the pump has to be commanded on. And and both power and ground are at supplied by the AIC Driver.

I guess you could unplug the pump, then use. Test light form battery negative to the black wire on the pump.
Truck off. Key Off. If what you say is true, the light should come on.
Then go unplug the AIC Driver and see if the light goes out. If it does, it’s the driver. If it doesn’t, you have a short to power. (But I doubt you do)

 

Okay, there are two connections on the air injection control driver - Removing the one with 5 wires changes nothing, light stays on. Remove the one with the white and black wire, it shuts off. Removing the 50A A/PMP fuse also turns the light off.

Checking resistance - whether the 5 wires are plugged in or not, it's low between the two pins on the controller.

Looking at the wiring diagram, it looks like the controller is acting as a relay, it should probably be default off, right?

Not as worried about that as the ABS controller at this point though.

The diagrams say that the fuses connect to the battery, does that mean that they're supposed to be constant power?

Any hints on how to get the ABS controller connection off? I've looked at a number of pictures of it, as well as it in place, and I'm not seeing anything that moves easily enough to tell me that I'm not just ripping it apart.

I'm starting to be afraid that it was a lightning strike - both controllers are very close to each other, and both on the passenger side. We lost a Mazda last year to what we suspect was a lightning strike as well.

Again, thank you very much for your advice.

 

So that means the driver is bad, something caused the driver to short internally.

I mean if the ABS pump runs constantly even with the key off it really can't be anything other than a failed ABS module. If I recall correctly the ABS connector uses a sliding latch.

You should be able to find both modules used relatively cheap, just need to match the part numbers for the ABS as there are several different ones depending on the configuration of the truck.

For both modules to fail in the same manner at the same time like that it would have to have been either a lightning strike or some other kind of electrical surge from either jump starting or connecting the battery backwards.
We were helping a member on here awhile back that had a dead truck we're pretty sure it was a lightning strike, pretty much every module got taken out.
Wonder if anything else got fried, does the truck still run?

 

Truck still runs. Actually, moved it to a better position for working on it.

After getting rid of the two big loads and getting the battery charged up, I should be able to pull the codes. Just have a bunch of appointments tomorrow.

I HOPE it is only those two modules if it comes down to it. Replacing the ABS controller will be a pain. Sourcing a not expensive one is going to take a bit.

 

Abs module shouldn't be too hard to change if the screws come out, you shouldn't need to change the hydraulic part.

 

Okay, with the secondary air injection driver unplugged, as well as the ABS fuse, I was able to start my truck and keep it running.

Oddly enough, the only code it is throwing is P1613 - "Secondary Air Injection Driver Malfunction" - Jeez, I wonder why?

But it is also showing it to be in 4-Low, which I darn well know it isn't. It also doesn't do anything when I move the switch.

But I'm getting 12.6V when the engine is running, which seems low.

So I might be up to 3 modules, possibly a battery and/or alternator.

I'm sad, this truck has been so great to me. From North Dakota to Alaska to Florida.

Edit: Found a truck of the same year in a pull-your-part yard. Should be around $40 each if I understand their pricing. It's only a 4x2 though, so no 4WD controller with it.
I can stand $80-120 easy.

 

Dang.

Sounds like a failed alternator and 4wd ECU, not too hard to test them.

https://www.tacomaworld.com/threads/2nd-gen-information-diagnostics.784008/#post-28042155

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

The ABS and 4wd ECU part numbers have to match what you have.

You may also check the sites below for used modules, you may also look around on here as 4wd ECUs occasionally pop up for sale by people the to swaps.

https://www.hollanderparts.com/
https://www.car-part.com/