Toyota says 08/2000-2002 4Runners all got this. That's pretty much going to be all 2001-2002 4Runners. (Actually all later 5VZFE engines so some Tacomas and Tundras.)

DIRTY! Must Clean! {ad for Simple Green goes here}

The Victim:

These are going for $625 from discount Toyota dealers. They are NOT cheap. I bought one though because I was getting all sorts of codes pointing to the TB...and at 17 years...the old girl was due a bit of an indulgence.

So this is my old one...

...let's take a look inside!

But first we CLEAN!

Cleaned and cleaned some more. Used Throttle Body cleaner spray. The residue inside the TB is just so gummy. I used half a spray can.




That's MUCH BETTER! {ad for Simple Green goes here}

Before I started cleaning I was wondering how the heck the recirculating gases got into the TB. No holes!

After cleaning...there they are! 4 holes! That's how much sludge was in my TB.



Dang that picture makes me want to clean it again.

Also...you can see a bit of sunlight now on the top and bottom. It doesn't close all the way.

So what is this thing? A Pedal position sensor? Can it go bad? What are the symptoms?




I didn't take it apart further as I really didn't want to have to fight a bunch of coil springs....and I don't know if I've ever heard anyone complain that it's a problem.

OK, onto that little rectangular plate on top:



Ewww...this is where those recirculating gasses come in...and boy it needs a cleaning.



That's much better!



Now, on other throttle bodies...isn't there an IAC that controls this flow? So it must be controled outside the TB? It's hard to see, but the tube does have a hole directly into that chamber. Those 4 little holes go straight into the TB air passage. I really can't see where there's anything controlling the flow here.

So I unbolted the TPS.



Then I unbolted the big plastic cover.



I didn't think I needed to go further and remove this stuff. We're looking at gears...and a motor buried in there. Everything looked fine.

Plus more coil springs. I don't really want to release them. When you look at everything they stuffed in this thing $625 starts to seem more realistic.

So apparently here's the bugaboo...the TPS. You can't buy this new anywhere...and they fail. So let's rip into this guy. Code on top is 89452-35030. They mold the edges of the unit around the top cover. Just carefully pry the plastic edging back and then remove the cover.




You will see a rubber seal. Remove that and then you will get to the "circuit board".



Pulling up the circuit board (carefully as it is soldered to the external pins), you see 2 sets of brushes/contacts.

So this thing is simply 2 potentiometers inside. I used good contact cleaner and Q-Tips to clean all surfaces and I GENTLY pulled up on the contacts to move them a hair so they should make firmer contact.



In all...it looks like this thing really should last forever. I wonder how picky the dang ECM is.

Tps (sitting flat...like so):

Resistance (ohms) Before and After cleaning:
Pin1 to Pin2 : Before = 1.05k ; After = 1k
Pin1 to Pin3 : Before = 347 ; After = 190
Pin1 to Pin4 : Before = 1.76k ; After = 1.78k
Pin2 to Pin3 : Before = 1.3k ; After = 1.16k
Pin2 to Pin4 : Before = 1.7k ; After = 1.66k
Pin3 to Pin4 : Before = 1.96k ; After = 1.9k

Resistance (ohms) Before and After cleaning while held open:
Pin1 to Pin2 : Before = 1.92k ; After = 1.88k
Pin1 to Pin3 : Before = 1.97k ; After = 1.96k
Pin1 to Pin4 : Before = 1.76k ; After = 1.78k
Pin2 to Pin3 : Before = 750 ; After = 680
Pin2 to Pin4 : Before = 200 ; After = 97
Pin3 to Pin4 : Before = 590 ; After = 560

So not a huge difference after cleaning...but enough? All values but one had less resistance and that might have been because I wasn't holding the spring open fully for that one value. Would it work better?

I'll probably never know as I don't plan on installing this TB back in my car. It'll go on the shelf if someday I do need it again.

I'd be interested if someone took a known bad one and cleaned it and tried it.

Also...I was reading on a Taco forum that to reinstall this TPS:

2003 tacoma tps 4 pin | Tacoma World

-Mike

Might want to look at this thread
Helpppp meeee haha

Thank you for writing this thread. The breakdown, cleaning resistance readings and specially the anatomy of the tb is really helpful.

very nice info, thank you for posting.

Great thread. Thanks for sharing.

Sent from my SM-J337V using Tapatalk

Are you referring to the Plenum ground?

That bolt was super tight on my car. Pretty sure I had to move that diag port thing when I did my plugs at 200k miles....and my driveability issues persisted.

-Mike