Limp Mode: Code P2103. Please Help me

Just picked up my first tacoma last Monday and I'm been having a lot of fun fixing it up. Here's my current problem: I'm getting two engine codes - P2111 (Throttle actuator control system stuck open) and P2103 (Throttle actuator control motor circuit high). The big one I need you to help me on is how to diagnose and fix P2103. Here's a quick background on the truck.

Truck had one owner and was a daily from 2009 to 2019, during which time it racked up 226,000 miles (current reading). From 2019 until yesterday, it was parked and didn't move. Enter stage right: Me. I picked it up over the weekend for dirt cheap from a family friend and I spent the entire weekend working on it. All it needed to start up was a new battery. Right after startup, I was getting two codes; the first one went away fast, but the one that lingered was P2103. With the battery unplugged, I took apart the air intake system and cleaned it, and then I removed the throttle body and cleaned it with throttle body cleaner. I put it all back together, reconnected the battery, and several tedious things happened:
1) I still have P2103
2) I have the new code - P2111
3) Idle is jumping to 1900, then falling to 1600, and constantly repeating
4) The car drives, but its in limp mode and won't exceed (somewhere around) 2k RPM
So two and three on that list occurred right after I cleaned the throttle body. Could I have done anything that you know of to directly cause these to occur?
And my main question: What steps do you think I should take to to diagnose and fix the code P2103?

In all honesty, most of my experience with vehicles has been working on old, carbureted Harleys and Kawasaki motorcycles, so all this electronic stuff is a learning curve for me. I'm asking you for help because you seem like a very helpful community, and I bet you could figure it out.

Thank you very much,
Jive

 

Check your ETCS fuse in the underhood fuse box, I have seen them blow on Toyota's after a dead battery.

 

Dm93,
I had the same Idea. I checked the fuses before I cleaned the intake. I didn't notice any problem with it visual, but the top of the underwood box had an extra of the same fuse so I switched it to be sure. No jive - the codes kept up.

 

Being that it has been parked for several years odds are high that rodents have chewed on stuff, you need to give all the wiring under the hood and under the dash a good lookover for chewed wires.

 

Dm93,
That's a good point. I noticed a cracked open acorn near the sparks, but other than that the critter was rather subtle. What you say is definitely a good lead. Besides from the obvious signs of chewing, is there anything more I should look out for?

 

Wires that have gotten rubbed/pinched by something or gotten against something hot and melted, also corrosion in connectors could be another factor depending on how it was stored.

 

My brief, very brief, research says that this code(P2103) is set when the ECU doesn’t see the correct current at the throttle body. Notice it says “current” and not voltage.
The ECU monitors current. (The pink and blue wires, Pins 1 & 2).

My understanding is, its basically 4 things that could cause your problem.

1. Wiring
2. Something stuck inside the throttle body keeping open.
3. Throttle body (bad or sticky spots on throttle valve causing high current draw)
4. ECM

I’m with @Dm93 on this one. I’d head straight to the wiring first. (Start at the throttle body)
As # 3 and 4 are very unusual on these trucks.

FWIW, P2111 isn’t really worth messing with until P2103 is rectified.
(Seriously, the manuals says in short “fix other codes first”)

 

@TnShooter ,

Thank you for the research! I'm still learning about all this electrical stuff, so thank you for pointing out the terms current vs voltage.

I found the attached diagram that I'm going to use as a basis for when I check resistance. I have a question about it and I hope you could help me.

If you look at 2, it says to unplug Throttle body connector and ECM connector. So when I go at it with a Multimeter, I should connect one probe to the Throttle body connector side and the other probe to the ECU connector side. Doing this will tell me if there is a problem with the wiring between those points. Is my understanding correct?
Then, I'll touch only one probe to the mentioned connector and the other to apart of the frame to see if there is an improper ground.

I want to learn, so I really am grateful for all the advice!

 

You are not looking for a ground in this step. You are looking for NO ground connection. A connection to ground would be a short to ground.

Other than that, you are correct

 

Clean the throttle body well. Sounds like a sticky TB.

 

That’s a possibility.

I believe the code is set if it sees 8A of current. Which seems like a lot. If it’s sticky, I bet you’ll know it fairly quick.

 

Correction, if more than 10A is detected. P2103 is set.

 

@Dm93 ,
It was stored in a backyard, parked on dirt, without covering or anything. It sat through multiple very cold winters and very warm summers.

 

That what I hoped as well, so I unmounted the Throttle body and cleaned it. The Code is still there. With the battery unplugged, I moved around the butterfly valve inside the TB and it didn't seem sticky at all. Do you think I may have missed something, or at this point should I look for a different problem?

 

TnShooter, I noticed that in my research as well. I'm going be returning home so I could work on the car this weekend, and so far this is my checklist in an attempt to diagnose the problem
1) Check to make sure all hoses, wires, and screws I've interacted with are fastened/secured (this is the guide I followed for cleaning the MAF and TPS, btw)
2) Use a Test-light to check ETCS fuse #19 in under-hood fuse box again (there is only one fuse related to the ETCS, to my understanding)
3) Check resistance to the TPS, and between the ends of the ECU-to-TPS harness (following the information in previously attached link)
4) Trace wires, starting at the throttle body and going from there. I'll be checking if any areas of any wires are rubbed/pinched/melted/corroded)

Do you think I should add anything to this list for now?

Also, for #3, there's six prongs on the TPS and the TPS harness, but these instructions only say I need to measure 1 and 2. What do the other four do? This engine manual seems to describe them near the last page, I think you may understand better than I could.

Thank you very much.

 

Sounds like a solid plan.

As for the other wires on the TB connector. You do nothing with them.
The 2 wires it says to test are the wires the ECU monitors for current draw.
The others don’t really pertain to the P2103 code.

 

That sounds like a good gameplan, I'm not big on resistance testing for checking wiring integrity but it should work for you since your likely dealing with a broken wire.

The wires at the Throttle Body are:

Pin 1 Blue (Motor Control - (M-))
Pin 2 Pink (Motor Control + (M+))
Pin 3 White/Black (Sensor Ground (E2))
Pin 4 Green/White (Throttle Position Sensor 2 Signal (VTA2))
Pin 5 Blue (5V Reference (VC))
Pin 6 Green/Black (Throttle Position Sensor 1 Signal (VTA))

 

I guess I should mention, make sure your meter set to the correct setting and scale.
As the test calls for Ω and KΩ

 

During fail-safe mode, the ECM cuts the current to the throttle actuator off.

I guess you could disconnect the harness on both ends and supply power/ground to a low wattage light and check for the ability to carry current?

I guess what I am asking is, how would you check wiring integrity?

 

@TnShooter @Dm93

I just got back home an hour ago and got to work. Fuses were fine.

Right off the bat, I'm noticing that the resistance between Throttle body assembly's is very slightly off. The multimeter is reading .22, as opposed to the specified minimum of .3 - is this a big enough difference to cause the code?