1994 E420 Throttle Valve Actuator
 

I own a 1994 E420 at 125000. The wiring harness has been changed about 10000 miles ago. The car started to idle really rough and stall then it just wont start without the gas pedal. When it does start it wont stay idling and will stall if you let off the gas pedal. I took it to John Holtz Mercedes of Rochester, NY and they claimed that there were numerous codes from different modules but one for throttle valve actuator as well. How much does this cost for my car?
What is the part number?
What does it look like?
Lastly how easy is it to replace?

I plan to do it myself if I can. The dealer wants $2400 for it.

Thank you in advance for all your help. I did search the forum but did not find the picture and how to remove info for my car.

Welcome,
Throttle actuators do fail (not often) & do require replacement.

Mounted on the intake manifold, takes approx 1.5-2 hrs to replace.

I would start by CLEANING the throttle actuator, using a "scotch-brite" pad I would scrub the inner housing & butterfly. Takes about 1/2 hour.

List price depends on the VIN of the car in question...MB list is APPROX $1500.


There are "remans" available for less that 1/2 of that MB list price.

Price also depends on whether you have ASR or not. Do you have ASR? It seems to me ASR cars are much more prone to failure - one rarely ever hears about a non-ASR car having a problem. There isn't a code that says "your throttle actuator is bad" so beware of anyone that tries to make it sound that simple - they may just be seeking your $2400. There's lots more information in the archives here, do a search above, and here: http://pages.prodigy.net/jforgione/MB_S500.html which is a car with ASR.

I've not seen rough idle due to a failing ETA (Electronic Throttle Actuator) but there's a first time for everything. The history of my ETA and others is contained in MENU#24 on my pages.

Also get the codes that were read to help you diagnose the 'complete' picture for your car. We can better help you.

When you are able to finally start the engine, does it idle poorly and smell like hell (super rich mixture smell)? Do you have to go really gently to get the rpm's to rise?
Why do I ask? Those were my symptoms - fixed after replacing the ETA.

If you get a rebuilt unit, plug it in to the harness, and test it for operation, before installing it (just in case it is DOA - don't ask how I know to do this).

Good luck!

-Larry

PS: Jim's webpages have a lot of useful info...spend some time there.

If you need a rebuilt check out www.4mercedes.com . Quite a few members have used their services(including me) and have been very satisfied.

Chris

Any kind of update?

First of I want to thank you all for your input and advice.

I want to make a few things clear and add more information. The car originally belonged to my father. He gave it to me after it developed the problem that I am going to describe in detail. I took it to John Holtz Mercedes of Rochester, NY back in November. At that time the dealer recommended a throtle valve actuator ($2400 :( ), cam sensor ($360) and a harness ($1650). They said that there were numerous codes and suggested that I drive around and come back when the CE light comes on again as they reset all the stored codes to see which ones come back on.

The problem with the car started with the car going limp as many of you described all of a sudden from idle along with roughness. It never went limb on the highway. The problem evolved into rough starts or not starting at all. The last phase was not starting unless you pump the gas pedal and hold it after starting at 1500 rpm or higher. As soon as you take your foot of the gas the car stalls. It simply cannot maintain idle. While the gas is applied it runs fine.

Anyway going back to the diagnosis I could not afford the repairs in November so it sat in my driveway for 6 months. I took the car in to John Holtz again since the CE light had come on shortly after their reset. This time they came up with a bill totaling $6922. Here is what they have added to the previous bill with part numbers:

124-545-3632 CC/ISC Control Unit $1500
000-094-01-4888 MAF sensor $312
004-151-78-0188 Starter $560

So what they are saying is that I need all the previous repairs along with the above three. A little note is that the starter is fine but since I cranked the car so much that I think the battery is weak and needs to be recharged. That is why they think that it is bad because it makes a funny sound when you crank.

The wiring harness was changed withing the last 4 - 5 years. I dont know if it could have gone bad so soon. MAF was changed 3 years ago because CE light came on.

The CC/ISC Control unit is dead according to the dealer and that is why it wont start and idle.

Sorry this is a long post but here is my dilema:

I asked for the codes they pulled and they said they did not save them and some other excuses and did not give them to me.

I just dont know what to do. I think the harness, MAF, starter, and maybe even the throtle valve actuator is just not needed. My gut feeling is that the control unit is the only thing needed but I am not sure.

What do you guys think. The car wont start. If you try long enough (more like until the battery is dead) sometimes it starts and you have to hit gas right after it starts and hold it to keep it running.

I thought about changing all the parts my self and even told the dealer but they told me that the MAF and the actuator need to be programmed to the car and I would have to take it to them for programming.

What do you guys think? What should I do? I am kinda handy with the tools. I have changed alternator, brakes, starters, and even engine oil. :D Do I need all these parts? Does the MAF and actuator need programming? What part is most likely to cause the problem? How easy is it to change the actuator?

Any help would be appreciated greatly. Thank you.

Wiring harness: check the connection just before it plugs into the MAF (Mass Air Filter);use a knife to 'carefully' cut the outside sheath to expose the inner wires. If it was changed, then the wires will be 'perfect'. If they look crumbly, cracked and brittle, then the wiring harness MUST be replaced.

In fact, it it's bad, then that, most likely, caused the EA/ISC/CC to go bad. At least, it CAN happen since the wires short and/or cross connect which can cause that modules (and others) to fail!

The MAF can be "cleaned" if it's still good, just contaminated; see MENU#4a for decontamination of an MAF.

There's alot more that can be done but you need get these items checked out and repaired first. . . unles you decide to buy another car.

I did not know you had a new harness - Glad to hear it.
When you first turn on the ignition, do you hear the throttle actuator move/click/whirr?*
The same crappy wires that were used in the harnesses, were used in the throttle actuators (my actuator no longer contained insulation on any of the wires!).

*remove the airfilter housing so you can see/hear better.

I'm not so sure I would go back to that dealer that you went to.
The actuator will learn on it's own....there is a post on this site with the procedure-so don't worry about that part.
Replacing the actuator isn't too terribly hard - buy a new gasket, and some of the rubber tubes that are really close by - they're brittle and tough to remove in one piece (just like the gasket).

Very, very unlikely that there's anything wrong with the wiring harness if it was changed 4 or 5 years ago. You have a really bad dealer there - one of the worst stories I've ever heard. You need to find a good independant shop or dig into it yourself. You can read the fault codes yourself on the 38 pin diagnostic connector in the engine compartment. Does the car have ASR? Is there an ASR warning light on instrument panel? Is the light on?

Hey, guys . . he needs to take the steps I outlined.

1) a DEAD EA module will cause the car to do EXACTLY as he describes. Since EAs don't just go bad on their own, it's logical to conclude that the wiring harness may be the cause.

So the W/H needs to be checked to ENSURE it's good FIRST, then try to get the car running. For that, a good EA is needed. Once he's there, then the ETA can be checked. . . but first things first!

I feel like I have my own 800 support line, thank you all.

Larry Delor:

I do the throttle actuator move/click/whirr. The sound continues until the car is started. Is that normal for it to keep on making the sound?

deanyel:

My car does not have ASR.

JimF:

What is the difference between EA and ETA?

Do I need any special tools to change the actuator? Does the MAF need to be reprogrammed by the dealer?

Thank you.

I wasn't able to hear mine once the engine was running - that doesn't mean it didn't cont. to make noise though. (at least it's making noise - doesn't mean it is good though either)

The ETA is the actual throttle body - the EA is a module.

No...nothing too fancy. A good light, long needle nose pliers (to get springs on/off) a hex bit, and a skinny longer screwdriver to loosen the MAF clamp.
Also, add some plastic vacuum tubing to the extra parts I mentioned earlier.

The MAF shouldn't need to get programmed.


PS: pic of EA module attached

Thanks,

It seems like the dealer is trying to take me for a ride and the fee is $6900. At this point I think I am going to try the repairs my self since I dont need any reprogramming for any of the parts they mentioned. I will post back here as I have questions throught out the process.

So I will check the wiring harness first and report back tomorrow. Thank you all.