# Throttle body bad?



## 94mx5t (Apr 3, 2009)

I have read and searched. I am not a car forum noob, so help me out guys!
Car: 2000 Jetta GLS 2.0 manual 80,000miles

My girlfriend's car is experiencing some odd issues, and I am hoping that you can help me not spend unnecessary money.

*Currently I am looking at replacing the throttle body.* 

*I am not using a vag-com, but an odb2 scanner.* First here are the codes that we pulled, and then the symptoms:
17987 - throttle body control/actuator
17952 - angle sensor 1 for throttle actuator
16505 - tps - implausible signal
16725 - camshaft posistion sensor
17663 - coolant temp sensor
16984 - closed throttle position malfunction
*Symptoms:* 
1. Harsh idle droop. Does not matter what the conditions are. If the car is started or the gas is touched the idle will drop down to about 400 and then bounce back up to about 8-900.
2. Symptom number one will occasionally cause the car to stall. This only seems to happen at low speed.
3. Air conditioning: this is a fun one! AC works completely fine during normal cruise, i.e. anything above 2,500rpm. Independent of whether the car is in gear or not. In neutral, raise the rpm, or cruise on the highway and the AC works. 
*What I have tried:* 
1. Adjusting the throttle body cable. Removed the slack. This helped low speed jerking of on/off throttle, but did not solve the problem.
2. Ran the throttle body alignment. This seemed to do nothing. 

Timing belt was done about 20k ago, so I am not particularly worried about the camshaft positioning sensor. I do not think it is causing the driveability issues. 
Alright, let's figure this out! I have some free weekends this months, and I need to fix this before I spend the remainder of my tax return.
Shane
94 miata DIY turbo


----------



## jetta09black (Mar 12, 2009)

*Re: Throttle body bad? (94mx5t)*


_Quote »_
"1. Harsh idle droop. Does not matter what the conditions are. If the car is started or the gas is touched the idle will drop down to about 400 and then bounce back up to about 8-900.
2. Symptom number one will occasionally cause the car to stall. This only seems to happen at low speed.
3. Air conditioning: this is a fun one! AC works completely fine during normal cruise, i.e. anything above 2,500rpm. Independent of whether the car is in gear or not. In neutral, raise the rpm, or cruise on the highway and the AC works. " 

Sounds like a vacuum leak and/or you need to clean your TB....
Check for vacuum leaks and repair them and clean your TB then clear the codes and see which ones come back.


----------



## 94mx5t (Apr 3, 2009)

*Re: Throttle body bad? (jetta09black)*

I drove the car this weekend and I forget to mention some important facts.
Initial engagement of throttle is abrupt. For example, when in gear and cruising, if I let off the gas completely and reapply soft throttle it will give an uncomfortable jerk. Not horrendous, but noticeably uncomfortable.
To clarify, I think it is the Throttle Positioning Sensor. From what I have read the TPS can not be replaced individually and I would need to replace the entire Throttle Body (which is why I put that in the original post).
I have time blocked off this weekend with a second set of hands. I am going to check all the vacuum lines and clean the TB. Hopefully this can magically cure the drivability issues.
Anyone have any input?
Thanks,
Shane


----------



## 94mx5t (Apr 3, 2009)

*Re: Throttle body bad? (94mx5t)*

Can we also confirm that the TPS can *not* be purchased separately from the throttle body?


----------



## sgolf2000 (Mar 2, 2003)

*Re: Throttle body bad? (94mx5t)*


_Quote, originally posted by *94mx5t* »_Can we also confirm that the TPS can *not* be purchased separately from the throttle body? 

that is correct you have to replace the whole thing. i bought a used in good working condition on here for i think 80 bucks. how did you run a throttle body alignment without a vagcom?


----------



## Mk3ChrisXx (Apr 10, 2009)

*Re: Throttle body bad? (94mx5t)*

i am having the same exact problem with my 95 jetta. my tranny was going and finally blew and thought it might be that but still does it. if you end up replacing the tb let me know how it goes.


----------



## 94mx5t (Apr 3, 2009)

*Re: Throttle body bad? (sgolf2000)*

Looking through more posts about the throttle body alignment, it does not look like we did it correctly. This was a couple months ago when we tried it, and had gone off of instructions similar to this:
_disconnect the battery for a while (i dont know, 10-20 minutes?), reconnect everything, and then "prime" the engine. By this i mean turn the key in the ignition, BUT dont fire it...you'll hear the fuel pump prime, and then leave the key in that position...if you go to the engine, you'll hear the throttle body aligning. it'll take a few minutes, and then you'll hear it stop. its now aligned itself._ 
Not sure if it did a single thing. Certainly did not resolve the issue.

So even if I bought a replacement TB, I would still need to do a proper alignment of it with a vagcom anyways?

I am starting to think I need to get one... Reading up on what and where to buy now.


----------



## Jay-Bee (Sep 22, 2007)

*FV-QR*

I did the key to "on" for 3-4 minutes thing when I removed and cleaned my TB and everything worked fine, but for a new one I would be running the TBA with vag-com.
They key forward thing is like a mini-calibration, and not a full throttle body adaptation.
I say this because I did a TBA on mine before with vag-com, the sound it makes during the procedure is entirely different than the key to "on" step.


_Modified by Jay-Bee at 1:12 PM 4-10-2009_


----------



## 94mx5t (Apr 3, 2009)

*Re: FV-QR (Jay-Bee)*

Holy crap! Reading about the vagcom is not something that can be done in a day!

So this crazy vagcom thing can do a throttle body alignment. Ok. The TPS is inside of the TB. 
Is doing a TBA going to have any effect on the TPS?
I am coming from the world of Mazda where this magical vagcom does not exist, so bear with me.


----------



## Jay-Bee (Sep 22, 2007)

*FV-QR*

The TBA cycles the motorized throttle body through various states (idle, part throttle, WOT) and adapts the TPS to recognizes those angles of the throttle plate movement.


----------



## garage_life (Jan 20, 2004)

*Re: FV-QR (94mx5t)*

yeah vagcom is indeed magic, my car wouldnt start at all.. after 10 minutes with vagcome it was back to life.


----------



## iSteven180 (Dec 19, 2008)

*Re: FV-QR (garage_life)*

I was just wondering, What is a VAG-COM? Is it like a Code scanner? I was looking at one on eBay and I Think I have an idea of what it does but just to make sure can someone explain it to me? I plan on buying one to save me money on code scanning.
Thank-You


----------



## mrdub27 (Mar 25, 2002)

*Re: FV-QR (iSteven180)*

go to Ross-tech.com


----------



## Jay-Bee (Sep 22, 2007)

*FV-QR*


_Quote, originally posted by *mrdub27* »_go to Ross-tech.com










Meh... I can see buying the real Ross-Tech cable if you see yourself needing ALL the functions, but for basic scanning and reading some of the measuring blocks my 20$ Ebay cable has yet to fail me after a year of use.


----------



## duke_seb (Jul 29, 2003)

*Re: FV-QR (Jay-Bee)*

if u need a TB i go one.....$40 shipped


----------

