Throttle Body Actuator - P0638

seabumb · December 22nd, 2010, 10:31

This code popped up on my 2011 Golf; priority 2 (7500 miles). There is no noticeable difference in the engine performance or driving. I would not know there was a problem except for the ping every 7 seconds and the flashing glow plug indicator. My question here is this: Since the nearest dealership is over 150 mile from me and I don't want to do further damage to the car, does anyone familiar with this code know if the car is safe to drive to the dealership in Houston or do I need to have it towed?

Considering it is not in limp mode and it appears fine I am inclined to drive but as I said, I don't want to do further damage. I called to dealerships there and both had the same basic answer, "we can't tell you that until we hook it up to the computer to see what is actually wrong..."

Thanks for any help or suggestions with this.

DanG144 · December 22nd, 2010, 10:36

I would not worry about driving it to the dealer.

crashtested · December 22nd, 2010, 12:14

Call the dealer? If they want it towed it'll be on their bill so no harm, no foul.

Rod Bearing · December 22nd, 2010, 12:50

Pull the ground cable off the battery for a few mins then put it back. Drive the car normally for a while afterwards.

That same code recently appeared out of the blue and on mine the dealer did what I just described.

It has not returned.

MayorDJQ · December 22nd, 2010, 12:51

Do you have 2yrs/24000 roadside assistance on an '11?

seabumb · December 22nd, 2010, 13:48

Thanks for all the quit responses. I could never get the dealership to give me the radio codes. I don't know about VW but all my other vehicles, if you pull the battery you must reset the radio codes. I had to fight Honda about this with an Accord just to get the radio/navigation codes and don't look forward to doing that with VW. It is probably on here somewhere but with the VCDS is it possible to pull those codes?

Roadside assistance... since I am not technically broke, I did not even think about that. Can't help the gray-hair syndrome...

RPS99SHO · December 22nd, 2010, 14:14

I took my battery out to install my shifter and I did not get asked for a radio code when I started the car back up again.

~ Roman

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DanG144 · December 22nd, 2010, 14:30

I am not sure when it changed, perhaps 2001?, but the newer VW cars do not need a radio code when restoring the battery. The older ones do. This is as long as the radio is matched with the original vehicle it came with. If you move the radio to another vehicle you need the code.

MayorDJQ · December 22nd, 2010, 14:31

Quote:

Originally Posted by seabumb

Thanks for all the quit responses. I could never get the dealership to give me the radio codes. I don't know about VW but all my other vehicles, if you pull the battery you must reset the radio codes. I had to fight Honda about this with an Accord just to get the radio/navigation codes and don't look forward to doing that with VW. It is probably on here somewhere but with the VCDS is it possible to pull those codes?

Roadside assistance... since I am not technically broke, I did not even think about that. Can't help the gray-hair syndrome...

Well.....then break it. Leave the headlights on overnight. Call them up and say you tried to jump start it, but no luck.

seabumb · December 22nd, 2010, 14:42

LOL, thanks for all the great information. I will go pull the battery now and if it needs a code, go for option 2) "Leave the headlights on overnight..."

Thanks everyone.

MayorDJQ · December 22nd, 2010, 15:07

I would think that as long as it's running normally, and not flashing rapidly, it's OK to drive. The throttle flap works in conjunction with the EGRs and Intake Flaps to control PDF temps. The throttle flap may have defaulted to WOT.

When you shut the engine off, do you hear the soft "EEEEEEEEEEEEEEEEE" from the front of the engine?

seabumb · December 22nd, 2010, 18:20

No 'eeeeeeeee' from the engine; no unusual sounds at all.

MayorDJQ · December 22nd, 2010, 19:01

Hmmm. You should be hearing an "eeeeeeeeeee" as the EGRs reset themselves. Maybe if one link goes bad, they all default open.

TDIzumSpass · January 8th, 2013, 20:00

I have the same code, and experienced the check engine solid and glow plug flashing combination, intermittently. In addition, the car will occasionally refuse to start (takes 5-10 tries to get it to start, after which it runs like crap for 5 seconds and then smooth). I ran across the following link, which told me to clean out the throttle body.

http://engine-codes.com/p0638_volkswagen.html

I removed the air hose between the throttle body and the intercooler pip, and cleaned the gunk out from around the round flap/valve just inside the throttle body (quite a PIA without removing the throttle body from the engine, which I will do the next time). Anyway, I just did this tonight so it's too soon to know if it will help.

JKC_NC · January 26th, 2013, 13:45

Quote:

Originally Posted by TDIzumSpass

I have the same code, and experienced the check engine solid and glow plug flashing combination, intermittently. In addition, the car will occasionally refuse to start (takes 5-10 tries to get it to start, after which it runs like crap for 5 seconds and then smooth). I ran across the following link, which told me to clean out the throttle body.
http://engine-codes.com/p0638_volkswagen.html
I removed the air hose between the throttle body and the intercooler pip, and cleaned the gunk out from around the round flap/valve just inside the throttle body (quite a PIA without removing the throttle body from the engine, which I will do the next time). Anyway, I just did this tonight so it's too soon to know if it will help.

Yesterday morning I had a CEL + erratic throttle response on my way to work. Incidently temps were ~23F, the coldest morning of the season. I kept the RPMs up above 2000 for the rest of the way to work (10 mi). Drove at lunch and home again in the evening, the light on the whole time, but engine seemed normal.
This morning I ran errands, driving normally. The CEL light stayed on the whole time (but no other lights). I had the code read at AutoZone and got P0638: Throttle actuator control range/performance- bank1
Explaination: Failed TPS
Probable cause:
Failed accelerator pedal position sensor
dirty or defective throttle valve
failed throttle valve control module.
As the engine was by now nicely (and gently) warmed up, I decided to see if some exercise might help the situation. I drove the car hard for about 10 miles of acceleration/high RPM driving in 2nd/5th gear, giving it lots of WOT, revving up to 4000, and cruising between 2000 and 3000 with coasting in gear back down to 2000. About 1 mile into the 10 mile drive, I noticed the CEL was no longer lit. Got home and looked up the code and found this thread.
My question...is, if this is a sticky drive-by-wire sensor/actuator, are there parts of the drive-by-wire system that can/should be lubricated? My plan is to lubricate all possible sticking points, if possible, and not do anything else "unless the CEL or hesitation/surging return. I plan to chalk it up to the "cold" temps in the 20s. Do I need to have the codes cleared if the light is off? Any other suggestions?
By the way, I had an episode of the iced-intercooler roughness my first year, and this is not the same. And I'm aware of the "hill-cresting" or "stumbling" and this throttle thing is not related.
Regards,
Joe