P0638
 

Hello Folks, I've done some searches for P0638 and didn't come up with much. at least not for Diesels. the ones I've come across were Mimi Cooper S and E90 M3's that have seen this issue around 60K.
They said that P0638 is rare, it's a non wear item and that it should last the life of the car...

I have a 2011 X5 Diesel in the US. I just got the code today. Is this something to drive safely with? It's not in Limp mode or antyhing. I cleared the code with AutoEnginuity. Hasn't come back yet.
I didn't even think the Diesels had a tradition type Throttle-Body, etc?
Still learning. Thanks.
I've only test drove it for roughly 5 miles without the Check-Engine-Light coming back on. Wonder if it takes 100+ miles or what?

Thanks all.

p0638 throttle actuator out of range
 

Doing a google and reading a bit sounds like this is an error saying your fly by wire throttle control is out of the spec range. In isn't a throttle body error. I believe what is going is when you press the throttle say 25 percent the computer tells some actuator to move 25 percent but it moves significantly less or more than that according to a sensor and you then get the check engine p0638.

I do know but since it isn't in limp mode I would think it safe to drive. However it might mean your throttle cable is failing and may totally fail.which could be big.problem if in heavy traffic.
If mechanically inclined you might inspect the throttle stuff under the hood to see if.you can see a.problem. might be cured with some lubricant but probably not.
The problem should continue and likely happen more and more ... you should have it fixed. Seems to me any independent bmw repair should be able to fix this easily provided they can easily find what.is wrong.

Uh oh!

Throttle cable?!?!?!

There's no throttle cable and the throttle the car has is not for the purpose of regulating engine load. There is a throttle butterfly but it's there to have a smooth shutdown of the motor; it is also used during the DPF regeneration.

It does get shorted by soot & oil getting into the circuitry. So perhaps that's what is going on.

Once it totally fails the code will stick and you'll notice the engine shuts off like an old diesel tractor.

Until then you're fine.

Take a look here at what happens to the throttle: P2621 Throttle position , output signal - circuit low - Bimmerfest - BMW Forums

This fault points that there is high temperature detected inside the DDE(diesel engine computer) in the circuit that controls the throttle valve.There are couple of things that can cause this issue.It could be your bad throttle valve that is putting strain on the DDE and its raising the temperature or bad wiring.Or E-box fan is not cooling the DDE properly.And it could be more serious issue with DDE itself according to the rheingold(bmw diagnostic software).
Screenshot attached.

Very interesting stuff ninja!!!

Interesting how it says that's something blocking DPF regen -> add to the list of things the ECU checks before moving it from requested to active.

But back to the topic: you mention wiring and DDE fan but could this excessive temperature again be the result of dirt in the throttle circuitry similar to this

http://www.bimmerfest.com/forums/att...7&d=1411138413

That results in a excessive current being absorbed the the throttle to maintain a certain position?

While bad wiring is possible (often rodents or clumsy mechanics), the DDE fan is monitored directly by the DDE so it would be odd that is not directly detected.

Quite possible ZetaTre as we already know that throttle valve gets filled with CCV and egr junk.

On an ALH TDI it is called, more descriptively, the anti-shudder valve. It's operation is checked as the only installed defence against a runaway engine fuelled by lube oil through failed turbo seals.

Plus on ALH engine it helps to stop the engine smoothly and quickly (same use on our M57)by blocking the air but its operated by vacuum on ALH TDI.

throttle at 94% open
 

thanks for all the replies and info. I read up on some of your other postings with other codes, but still related to the Throttle-Actuator.
I can see the throttle close a brief second and then open back up 94%. It stays open while the engine idles or even accelerates. Only when the pedal is released do I see a brief blip of 30-60% open. Otherwise it pretty much stays open.. I guess on diesels they will stay open until the EGR valve is overcome by pressure or the run-away effect?

I cleared the code as step 1, but it hasn't come back on yet after around 40+ miles. I guess it's more like a ticking-time-bomb now? It will fail, just don't know when?

it looks fairly easy to access and swap out. Am I wrong here? :) no need for coding, etc.. I hope.

So the honest thing is to change it asap? to avoid getting stranded?


Thanks all. very useful info. Especially Zeta and ninja.. :)

DDE?
 

Geez, I really hope it's not soemthing to do with the DDE failing. How would that be a fail item? and if the e-fan isn't fully working, that would kill the DDE? how awe full is that! so the code p0638 is only a symptom of a larger issue? not necessarily the Actuator itself? Or possible more true to the picture Zeta posted with a gummed up actuator/gears etc?

Thanks. :)

I would say more chances are that your throttle actuator is going bad because it's known to fail because of oil and soot entering the electronics.But hard to pin point the fault at this moment just by the code.Regarding DDE fan,chances are less as zeta said that it's monitored closely.Best would be to run test plan via Rheingold if you can and software will guide through all the possibilities.Test plan only runs if Rheingold is connected to the car.

Another thing is that there are protections in place in the DDE to disable any component or sensor incase it's drawing too many amps.So let's say if you actuator is drawing too many Amps then DDE should disable it before overheating.

rheingold
 

This may be off topic, but how does one obtain rheingold? I've simply glanced through some forums, some say it's VM, some say it's direct windows, etc. I've installed INPA ISTA D/P, etc. on top of VM.
I don't have a good understanding of all the different 'snapshot'

Do I get more instructions via bmwcoding.com? or can someone help us figure this out? or PM?

Thanks.

also, Siemens/VDO $225 for a diesel x5 throttle-actuator. BMW-OEM is like $398. Safe to settle for VDO?
Thanks.

Can one clean the oil away?
 

If the problem is oil has contaminated the actuator could one clean it with alcohol and dry it out with a dryer? Then seal any oil entry point and then have it running again. Love a good lo to no cost fix!
If this works it might mean we all should check and cleanup the actuator?

I consider the x5 like a plane one needs to inspect and service to avoid in flight issues 😁

Well,

some of us have gone down the route of eliminating oil getting into the intake -> http://www.xoutpost.com/bmw-sav-foru...separator.html

I'd suspect that oil gets there through boost leaking (very minor, but builds up over time) through the shaft so it's quite challenging to fix.

As far as disassembling the throttle and cleaning it, I don't know if it can be done and being able to put it back together.

Is this diesel only problem?

I don't think it's isolated to diesels, but I believe diesels may be more prone to this issue due to what Zeta an others mentioned, due to the soot and oil, etc.
I read mini cooper s, e90 M3's, etc..

I finally got the codes again.
p0638 and 4687(Enhanced).
It was under these conditions:
------------------------------------------------------------------------------
Make: BMW Model: X5 xDrive35d Year: 2011
VIN:


MIL: On


Diagnostic Trouble Codes

Generic Powertrain

P0638 Throttle Actuator Control Range / Performance (Bank 1)


Freeze Frame for DTC P0638

Calculated Load 82 % Coolant Temperature 183 F

Engine RPM 703 r/min Vehicle Speed 1 MPH

Intake Air Temperature 196 F Air Flow Rate From Mass Air Flow Sensor 1.18 lb/min

Absolute Throttle Position 20 % Absolute Throttle Position E 13 %


Enhanced Powertrain CAN

4687 Unknown Trouble Code Description. Please see your factory service guides for more any information.
------------------------------------------------------------------------------



So, not sure what to do next. Go ahead and replace the TB? should I go VDO/Siemens($225), or Genuine BMW oem($399)?
Do you think it's easy to change? 1-10, I think I can manage this as maybe a 5..

Thanks.

update:
Weird that the MIL light goes away after awhile...
Is that normal?
It drives just fine... anyway, looks like I should change this anyway.
Any advice on the difficulty and or parts? :)
Thanks all.

I had the same issue with my 09 35d. it was the from the oil in the throttle valve shorting out the circuit board in the throttle valve. Mine did not go into limp mode either. I diagnosed it then took my time watching eBay for a warranted used unit. I paid $150 for the replacement.

It is a very easy replacement, about a 2 on your 1-10 scale. Then reset the code and your done.

How was the DIY on this one? What was your take on it? any advice? :)
Thanks.

I didn't see a DIY on it in this thread so i put this together today.

Excellent contribution!!!! I've added it to the DIY section.

Thanks for the DIY and good buildup of confidence. :)
Does anyone know a good parts list?
e.g. TV obviously.
o-ring for TV?
Gasket for the EGR to Manifold?
Anything else? :)

Thanks all.

Well... Since you're going down the path of spending the money and replacing it, if it was me and my car, I'd first take it apart and clean it with some TB cleaner on the inside and some electronic contact cleaner on the circuit board.

Once removed, I would try to pry off the circuit board cover trying to do the minimal amount of damage possible. When putting it back, if needed, I would add a tad of ePoxy putty to secure it in place is feels loose...

Just a thought since, again, you've set your mind on spending the money on it. But concept is, you can't brake something already broken

But to your specific questions, I did remove it a few times and never replaced any of the seals. They are normally still good and malleable. I usually apply to the seals, o-rings and other rubber parts some NAPA Sil-Glyde Silicone Lubricating Compound.

Hello, I am curious if anyone has information about whether a throttle valve replacement is absolutely necessary. It's a $700 repair that I'd prefer not to make on my 2009 X5d. I asked dealership to run diagnostics for the check engine light and the prescribed repair was to replace throttle valve. I don't mind the check engine light staying on and the car does not go into limp mode. What's the downside of leaving it alone? I don't mind the minor shudder when the engine is turned off.

How will you be able to tell when a serious fault occurs that can damage your motor?

Also, WHY A DEALER? how much are they trying to steal from you for this?

Well, that's a good point. I'm glad you shared that. I hadn't really thought about it that way - thanks.

I was at the dealer for some recall work. It was indeed a poor use of $175 for the diagnosis. However, if I end up making the repair I will have my private mechanic do it ($700 vs $1100 at dealer).

BTW. Welcome!

Sorry the dealer scammed you for the 175.


Also, if you are pretty prompt in dealing with a CEL when it comes up, then troubleshooting is pretty easy: lights up, pull codes, fix.

People get into trouble when they drive around for a year or two with a CEL on, only taking it in when they notice driveability issues. But by then there can be a raft of codes and it make troubleshooting much more difficult.

Ive made it a habit to look for CELs on the dash when I am at lights, traffic jams, etc. Really amazing how common

Throttle valve plays important role in DPF reneration.If you leave as it,it could damage your DPF.

I'm not sure why you're stuck on $700 repair. Pierburg (thru FCP Euro) is the oem supplier. $236.49 gets a new one. Took less than an hour in my driveway. No coding required. CEL will reset on its own.

Just fix it.