# 17988 - throttle actuator b1 malfunction



## HilF (Jan 10, 2004)

i am getting this code *"17988 - throttle actuator b1 malfunction"* and my idle seems high. when i let off the gas, sometimes the rpms drop to about 500.
any experience with this code/problem?
96 mkIII golf, 2.0


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## [email protected] (Jun 5, 2002)

*Re: 17988 - throttle actuator b1 malfunction (white_r!ce)*

Sounds like your throttle body is acting up. Try performing a TBA, and try cleaning it. But, if that doesn't fix it, you may be looking at buying a new throttle body.


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## HilF (Jan 10, 2004)

*Re: 17988 - throttle actuator b1 malfunction ([email protected])*

i have tried a TBA. didn't work. said error.
now a TBA was tried on a different car too and the same error msg came up. diff car is working fine though.
would it be the software or the actual TB that would cause the error?


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## keithsvw (Mar 22, 2004)

You must not have any DTC when you atempt the TBA . 
Unless you loss power to the throttle body you proboly need a new one.
It's somewhat of a probem!


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## momoVR6 (Jul 11, 2002)

*Re: (keithsvw)*

when I try doing the TBA on my car it says error as well. Is this possibly caused by having a chip? My car is a 98 VR6.


_Modified by momoVR6 at 12:43 AM 3-23-2004_


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## [email protected] (Jun 5, 2002)

*Re: (momoVR6)*

All of these conditions must be met in order to do a TBA:
http://www.ross-tech.com/vag-com/cars/throttlebody.html


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## Consch-Hofman's (Feb 5, 2004)

*Re: 17988 - throttle actuator b1 malfunction (white_r!ce)*

Just one more pre-condition: There must be slack in the cable when the throttle is released. check at the throttle body end and adjust with the notch and clip at cable housing end. If you still can't get ADP OK, there is a diognostic proceedure:
Start engine and let it idle (should be warmed up), go to 04-basic settings, chose block 140, typical (not specified) values are
140,1,engine load, 1.4-2.4 ms
140,2,idle actuator position, 65-85 %
140,3,Throttle valve potentiometer voltage, 3.0-4.0 volts
now select 04-141 
141,1,Actual position of throttle actuator, 65-85 %
141,2,Specified position throttle actuator, 65-85 %
141,3,Throttle valve integrator 90-170 (no units)
now select 04-142
142,1,Throttle valve emergency run position, 65-85 %
142,2,throttle valve minimum stop, 80-90 %
142,3,throttle valve maximum stop, 20-30 %
[Go back] 
Record this data and post here, maybe someone can spot the problem.
Oh: Almost forgot to ask: when you first turn ignition on (engine not running), do you hear a faint whining sound coming from the throttle body?
Good luck
C Schwenzer


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## HilF (Jan 10, 2004)

*Re: 17988 - throttle actuator b1 malfunction (Consch-Hofman's)*

this post appears to have potential..will give the vag a try and report.
cheers


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## HilF (Jan 10, 2004)

*Re: 17988 - throttle actuator b1 malfunction (Consch-Hofman's)*

block 140, typical (not specified) values are
140,1,engine load, 1.4-2.4 ms *1.85*
140,2,idle actuator position, 65-85 % *72.2*
140,3,Throttle valve potentiometer voltage, 3.0-4.0 volts *4.360*<----------








now select 04-141 
141,1,Actual position of throttle actuator, 65-85 % *71.8-72.2*
141,2,Specified position throttle actuator, 65-85 % *73.7*
141,3,Throttle valve integrator 90-170 (no units) *128*
now select 04-142
142,1,Throttle valve emergency run position, 65-85 % *72.2*
142,2,throttle valve minimum stop, 80-90 % *85.5*
142,3,throttle valve maximum stop, 20-30 % *24.3*


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## HilF (Jan 10, 2004)

*Re: 17988 - throttle actuator b1 malfunction (white_r!ce)*

http://****************.com/smile/emthup.gif


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## Consch-Hofman's (Feb 5, 2004)

*Re: 17988 - throttle actuator b1 malfunction (white_r!ce)*

Hi Hil:
Was out of the area for the weekend but "keithsvw" above is correct. The first pre condition for doing a TBA is "No DTC's in the Engine Controller", and you have "17988 - throttle actuator b1 malfunction" . Can you clear this code at least temporally or does it come back right away?
If it comes right back the bently and erwin both require many trouble-shooting steps which require a VAG 1598 test box. Ok: don't got one of those, but the objective is to determine if the problem is the throttle body, the harness, or the ECU. If you can get together with some else that has ABA OBD II ( 037 906 259 XX) , swap throttle bodys and see if the DTC will clear, If not try swapping ECU,s and see if the DTC is set in this one too. Now you at least know where to look.
If on the other hand it does not come right back, go to 04-98 and try again. It still may say adapt error. Don't worry, leave key on for 30 sec.s than key off for 30 sec.s, than key on and listen to the throttle body. It may sound like it.s doing a TBA all by itself. give it 30 sec.s then go to 98 as a measuring block and see what your ADPT status is.
This last is due to the fact that the ECU software was a bit of a moving target in MY-96 and in some of the earliest production TBA actually worked this way
Lastly as to "140,3,Throttle valve potentiometer voltage, 3.0-4.0 volts 4.360<---------- ", I will check a few vehicles this week and get back to you
Good Luck
Consch


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## cezrleo (Dec 10, 2001)

*Re: 17988 - throttle actuator b1 malfunction (Consch-Hofman's)*

I have the same problem as White_r!ce
I did the TBA and still had
140,3,Throttle valve potentiometer voltage, 3.0-4.0 volts *4.360*
I will be so happy if i dont need to buy a new TB. Please don't tell me i do.
I also have a GIAC chip in my car, could that have anything to do with these problems? thanks


_Modified by cezrleo at 11:47 PM 4-13-2004_


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## HilF (Jan 10, 2004)

*Re: 17988 - throttle actuator b1 malfunction (cezrleo)*

funny, i have a GIAC too, but i bet that's coinsidence.
uhh, i'm still hunting this problem down. 
its a pain isn't it?!
what does/doesn't your car do?


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## cezrleo (Dec 10, 2001)

*Re: 17988 - throttle actuator b1 malfunction (white_r!ce)*

I have no more CEL but i have the same throttle valve voltage. I did the TBA and it says it's ok, but it's doesn't seem to be.
When I start it up it revs to 2000 then unsteady back down to 1000. When I hit the gas it sticks at the current rpm's after i release the gas, then drops slowy back down to 1000 after a second or 2.
My car never use to rev that high to begin with so basically this sucks.
Did you first have code 17990 then this problem. Becuase I had that code, then i cleaned the TB and my MAF. After cleaning those code 17990 went away and 17988 came on. 
What is your car doing?


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## cezrleo (Dec 10, 2001)

*Re: 17988 - throttle actuator b1 malfunction (cezrleo)*

should i deffinitly not drive my car?
and if i need a new TB, break it to me easy 





















......


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## HilF (Jan 10, 2004)

*Re: 17988 - throttle actuator b1 malfunction (cezrleo)*

hehehe, i'm sure you can drive your car.
i've been driving my car like nothing is wrong. shiiiiet, i've even learnt to drive with the rpms dropping like a bomb once the gas is let off. makes rev matching a must when shifting *up*








i'm still sourcing out a tb to swap out.
i also still need to change all my vacume hoses (may as well - car is 8 years old)
will keep coming back to this thread until my problem is fixed.
all in all though, i have a feeling i'll need a new one


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## cezrleo (Dec 10, 2001)

*Re: 17988 - throttle actuator b1 malfunction (white_r!ce)*

The thing that i don't get is my car was running perfectly fine. My CEL was on so i checked the codes and i had code 17990 (idle adaptation limit reached). After reading up on that problem I cleaned out the TB real good, it had carbon all over the inside. Then right after i did that and put the TB back on my car I was getting code 17988, and now my rpm's are buggin. My car drove fine and rev'd fine before i cleaned it.
Could I have done somethign to cause code 17988? or what is the deal here















My car is also a '96, What would changing the vacume hoses do? Do they have anything to do with why my rpm's could be buggin?
thanks alot for the help. We will get through this together


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## cezrleo (Dec 10, 2001)

*Re: 17988 - throttle actuator b1 malfunction (cezrleo)*

I have a few friends that have OBDII vr6's. If i wanted to see if the TB was the problem on my car should I try out one of their TB's on my car to see what happens. And is there a chance of ruining one of my buddies TB's by doing this?


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## cezrleo (Dec 10, 2001)

*Re: 17988 - throttle actuator b1 malfunction (cezrleo)*

well i drove my car all over the place today and everything seems fine. my RPM's are normal, no more CEL. I could not be happier. I don't know why it was acting crazy but it all seems well now, but we'll see what happens, i'll keep you posted. 
thanks for the help and goodluck with your TB


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## cezrleo (Dec 10, 2001)

*Re: 17988 - throttle actuator b1 malfunction (cezrleo)*

just hooked up the VAG again to get the Throttle valve potentiometer voltage, and it is still high 4.4 volts








hmm, everything seems fine besides that though


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## HilF (Jan 10, 2004)

*Re: 17988 - throttle actuator b1 malfunction (cezrleo)*

hooking up other tb's should be fine. i don't think there'd be a rick of ruining someone elses. if you do, uhhh, just don't let them know


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## Consch-Hofman's (Feb 5, 2004)

*Re: 17988 - throttle actuator b1 malfunction (white_r!ce)*

Hi white_r!ce:
For the last couple of weeks have been comparing your data with data from cars with ADAPT-OK. There were eight cars in the study. Your data was very consistent with the group. About that voltage
140,3,Throttle valve potentiometer voltage, 3.0-4.0 volts 4.360<----------
you are within +.02 volts of the others. This voltage is the same one you see in 098. With key on, engine off if you slowly depress the throttle this should smoothly decrease to something like .760 volts. This is the TB load signal and has several uses throughout the system.
Now after looking the data over minutely this weekend I do see one possible anomaly. It is here:
141,1,Actual position of throttle actuator, 65-85 % 71.8-72.2
141,2,Specified position throttle actuator, 65-85 % 73.7

Within the group these numbers always were the same. Even if there was an outside influence to cause these numbers to vary they were in lock-step within .1% 
So it seems the servo in your TB is having a hard time being precise and your ECU is picky. The only way to know for sure is substitution.
The ABA G,J,P is the most common engine type to visit our shop and I have yet to see a bad TB so it sounds like getting a good one from a bone-yard would be OK.
Tell me how you make out.
Good luck.
C.Schwenzer


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## cezrleo (Dec 10, 2001)

*Re: 17988 - throttle actuator b1 malfunction (Consch-Hofman's)*

hey consch,
when you say "depress the throttle this should smoothly decrease to something like .760 volts."
what does that mean?








i have the same problem as white_r!ce


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## HilF (Jan 10, 2004)

*Re: 17988 - throttle actuator b1 malfunction (Consch-Hofman's)*

dude?!!? 
i bow down to you for your attention to detail.
i have a few measurements i look per the bentley...measurements seem to be off a tad...















this was off the bentley forum; *bold* type are my measurements
You can start by verifying that there is 5 volts across pins 1 and 3 on 3 pine harness. If there's not either the wiring is bad or the ECU. 
If that checks out *yes* ok you can pull the connector off of the ECU and place a meter across pins 33 and 41, you should see 1.6k to 2.4k ohms *0.96ohms*. 
Then go across 33 and 40, should see 1k to 2k ohms there *1.49ohms*. Same pins, open the throttle body slowly and watch the resistance, should increase with the opening of the throttle valve.*0.78ohms WOT, 1.58ohms part throttle* 
After that go across 40 and 41, throttle closed should read 2.5k to 4k ohms *0.82ohms*, open the throttle body slowly and the resistance should again increase with the motion *1.48ohms WOT, 158ohms max part throttle*.
the part throttle measurements were jsut the maximum ohms i got when opening the butterfly plate. decided i'd record them anyway.it waas a little more than half open.
so...does this make sense to you or anyone else?








_Modified by white_r!ce at 9:59 PM 4-21-2004_


_Modified by white_r!ce at 10:00 PM 4-21-2004_


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## cezrleo (Dec 10, 2001)

*Re: 17988 - throttle actuator b1 malfunction (white_r!ce)*

let me read it a few more times, then i'll get it


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## HilF (Jan 10, 2004)

*Re: 17988 - throttle actuator b1 malfunction (cezrleo)*

i tested to see if i was getting 5v. got it.
then i unplugged the ecu harness and tested the resistance over certain pins.
then noted resitance increase/drop as i opened the throttle body.
so i recorded the measurements in bold.
either its the wiring from the tb to the ecu or most likely, its the ecu.








i'll be borrowing one tomorrow to test it out. hope it goes well. might end up with a diff tb at the end of the day if it solves my problem. i can't stand this anymore.


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## HilF (Jan 10, 2004)

*Re: 17988 - throttle actuator b1 malfunction (white_r!ce)*

-------back from the dead-------
well folks, this is for furture reference incase some of you have similar problems.
turns out it was the throttlebody








i avoided buying one as long as i could but the fluctuating idle (causing vibrations due to motormounts) and the rpm dipping had gotten to me.
i bought a used one, cleaned it up, bingo. i wish it wasn't so, but if you are reading this and nodding your head, try to borrow somebody's tb first.
edit: thanks *Consch-Hofman's* for your help!! http://****************.com/smile/emthup.gif 


_Modified by white_r!ce at 12:24 PM 6-17-2004_


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## Throttle body actuator (Jul 7, 2021)

[email protected] said:


> *Re: 17988 - throttle actuator b1 malfunction (white_r!ce)*
> 
> Sounds like your throttle body is acting up. Try performing a TBA, and try cleaning it. But, if that doesn't fix it, you may be looking at buying a new throttle body.


I buy a new one but the code still exist


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## chrisqc (Aug 7, 2008)

Throttle body actuator said:


> I buy a new one but the code still exist


Did you clear the code and perform a throttle body adaptation?


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