1998 ML320 problems-Limp home mode - PeachParts Mercedes-Benz Forum

1994C220 · #1 04-29-2002, 10:35 AM

It all started out as to what my wife and I thought would be a peaceful Friday drive from Austin to Houston to visit the inlaws with our 4 month old son. It turned into the night from hell...

About 110 miles out on I10(Halfway between Austin and Houston), We decided to stop to grab a bite to eat....We stopped at and ate, and I left the engine to idle for a few minutes to cool down the truck. I turned off the truck and we went inside. When we came out, and we began underway....i noticed something was terribly wrong...The transmission would not go past 2nd gear! So I was on a major interstate, and couldnt go over 30 miles per hour. Our cell phones wouldnt work in the area, so we had to drive along the emergency lane till we found a gas station. I tried to turn it off and back on, but it didnt help, and I was beginnning to feel a little like a Mercedes victim. I called the rescue # and they said that they could send a tow truck out but that it was going to cost an arm and a leg cause the nearest Mercedes dealer was in Houston, and the tow trucks charge between 3 to 7 dollars a mile....plus 75.00...and I was around 95 miles from Houston.
Doesnt sound to good huh?

Heres the thing....The check engine light was on, and the rep told me that the truck had decided to go into this mode and that Id probably be better to have someone come pick us up, because the tow truck driver could only take two of us(Sorry baby Caleb), and that they would pick up the truck. I told him thanks, but that I was going to drive the damn thing to the nearest hotel and get a good nights rest before I decided how I would get back to Austin.
So we limped along on the access road, and all of a sudden, the car upshifted....!!! It was a miracle!

So, we headed home, and the truck drove fine.

What I want to know is what the heck happened. The next day, I checked the fuses on a hunch, and one of them was blown(Blower motor fan). I replaced it, took the truck out, and the check engine light went out....and has stayed off...Was this the cause of the problem?

Sorry for the long story, but I wanted to describe it exactly as it had occurred...Has anyone else had this limp home mode activate on them like this?

Thanks,

Gilly · #2 04-29-2002, 07:11 PM

Pretty sure that the problem is a replaceable part in the shifter called the range recognition switch. Had a number of these fail. Not alot of them failing lately, but it sure does sound like the problem we had with them. Part isn't too expensive, but I'd kinda tend to recommend the dealer does it. The shifter assembly needs to come apart, gets a little tricky.
Gilly

1994C220 · #3 04-30-2002, 09:18 AM

Thanks for your help, Gilly. I will call the parts shop today to check pricing. If you have the part #, would you please post it? I have driven the ML320 both yesterday and today, and it seems to be doing fine, but I definitely dont want to get stranded out in the middle of nowhere again.

I will get the dealer to install it here in Austin.Would you recommend any other service for an ML with 78K miles? I dont have the service records, and we have only had the truck for around 4 months.

Gilly · #4 04-30-2002, 08:32 PM

A few ideas. First of all, they should check for trouble codes in ETC (transmission control unit) to see if they agree that the range recognition switch had failed, it usually will leave a code for it, sorry, can't remember the code or description right now of what that code is. Sometimes this switch failing can actually prevent the transmission from going into gear.
On service ideas, first I would ask the dealer to do what is called a VMI (Vehicle Master Inquiry) to see if there are any outstanding service campaigns. The 98's had tons of them, and they would be free updates for you.
2 things that are often overlooked are the brake fluid flushes (due every 2 years) and the coolant flush (due every 3 years).
The coolant can be hard to determine if it was done. The brake fluid will look pretty dark if it's over 2 years old though. Should be yellow colored, if it's more of an amber or orange color, I'd get it replaced, they can check your brakes while they're at it.
At 60,000 miles, the truck was due for the air filter and fuel filter. The fuel filter was updated about a year ago to a longer filter, there are new hoses that need to be installed. Adds alot to the complexity of the job, because to install the fuel hoses, the left side of the rear seat needs to be removed to gain access to the top of the fuel pump (metal lid bonded to the floor in this area).
The truck also neds spark plugs (12 of them) every 100,000 miles OR 4 years, chances are the truck is over 4 years old. The build date (month and year) are on a black label on the body side of the drivers door jamb, if you want to check it out yourself.
Some are suggesting the replacement of the transmission fluid and filter also by now. It's supposed to be a lifetime fill. I really haven't been encouraging it myself (this would be 8 quarts or so of fluid at about $17 per quart, you're supposed to use this fancy synthetic ATF Mercedes sells).
Also if you have a clunking in the front end over bumps (more noticeable at slower speeds), there are redesigned front sway bar links that will fix it. Really replaced alot of them on 98's.
Let me know if you have other questions. These are good trucks if the mechanic understands the problems and corrects them. Someone who was in the dealer system when the ML was introduced should have a pretty good handle on it.
Gilly
ps I am home now and don't know the part number of the range recognition switch.

1994C220 · #5 05-01-2002, 09:28 AM

Thanks Gilly. I am having the truck serviced this weekend by a Mercedes mechanic that works at ******** here in Austin. He works on the side and was recommended by a neighbor that also is a 100% Mercedes family...although they have 3! .
I called the dealer to check the price...they call it a gear recognition switch, and it lists at $101.20. The service department said they could put it in for $217.00...But I am getting the fuel filter changed(updated), and the spark plugs definitely done this weekend. I will check the brake fluid tonight. Oh, by the way, on my last post, I was having trouble with wind noise, and everyone suggested changing out the door moldings...It worked like a charm. The ride is whisper quiet now.
My wife thinks part of the current problems we are having is my lead foot. I was averaging 95 or a 100 on the way to Houston last weekend. But on these long Texas highways, its hard to stay under 90.

I will keep everyone informed on this so that it might help someone else that may encounter this in the future. Thanks

Gilly · #6 05-01-2002, 09:55 AM

Hey You:
(You could give me a first name).
On the range recognition switch, I don't really think lead-footing it is going to affect it. We had lots of these fail on practically new ML's, and also cars used essentially the same part (if not THE same part). This was prior to 2000 when the "Touchshift" came out, on that system there are no replaceable parts at all. I would still "feel" better if someone would do a "quick test" (computer poll) on the truck and see if the range recognition switch makes sense. In the shop, I would first assume that the range recognition switch is at fault, but I wouldn't ask for/order the part based on my first impression like this. If you want to go ahead and replace it on my first impression, fine, but don't say I didn't warn you.
Instead of assuming hard-driving as a cause for this part to fail, I would think more along the lines of possibly fluid being dumped on the shifter assembly. It seems like when we get a failed one now, it's due to fluid contamination from the inside of the truck (coffee or soda, etc getting spilled on the console).
Glad the wind noise is gone. The weatherstrips were updated in the 2000 model year. Strange I have info from the 2000 ML update class that the weatherstrips are NOT retrofittable, but I have heard here at mercedesshop by several people that they have done it.
The labor price is probably about right when compared to the labor rate in our shop---at least a couple hours. The center console needs to be removed to get the shifter assembly out, then the shifter assembly is disassembled "on the bench" to replace the switch. It's a pretty good deal, as the "Touchshift" assembly (ESM, or Electronic Shift Module) is quite expensive. NO, the non-Touchshift ML's can't be upgraded to Touchshift, but then again that info is from the same class they told me you can't update the door weatherstrips

.
Make SURE you contact someone at the dealership to see if there are any outstanding campaigns. In my opinion, this is the most useful information I have given you so far. DO IT!
Gilly

1994C220 · #7 05-02-2002, 02:35 PM

Gilly, thanks for the advise..I will get the truck checked out for any error codes, and get them to check to make sure all of the recall work has been done.

I was wondering...can you see the fuel filter from underneath? And if you can, can you tell if it is the newer model, or if it still has the original filter.

The truck has been doing fine this week by the way. I have driven it every day, and it has performed flawlessly.

Carlos

Gilly · #8 05-02-2002, 08:26 PM

Carlos:
Unless you know what they look like, it's hard to tell. You can see a little of the fuel filter, it's above the frame rail on the left, just forward of the rear wheel. You'd need to look into the rear wheel well on the left side, just ahaed of the tire, up on the frame. The only place is sort of just under the lip of the black plastic fender well liner, you'll probably first notice the clamp that holds it in place, like a large radiator hose clamp.
Gilly

Fast Robert · #9 05-09-2002, 11:25 AM

Carlos,

98 ML owner here also. 117K miles

I just finished going through some of the items Gilly mentioned
(Brake fluid flush, coolant change, fuel filter upgrade, and rear pinion seal) and happen to have the "My Benzo" folder with me.

Fuel Filter:
The old part number: 163-477-02-01
The new part number: 163-477-05-01 ($51.00) ACK

Lines and hoses:
001-997-83-90 Clamp ($1.40)
163-470-37-64 Loop to 1634 ($16.50)
163-470-29-64 Line to 1634 ($14.50)
163-470-28-64 Line to 1634 ($18.50)

Labor = $120

Next are shocks/struts (doing them myself)

I'm interested in learning more on the level of difficulty (or not) swapping/changing the door moldings. The 40 mph thump is driving me nuts.

1994C220 · #10 05-09-2002, 01:42 PM

Robert,

I did the door moldings myself. I ordered them thru Fast Lane, and if memory serves correctly, I got both front doors, and they were 102.00 total(shipping incl). The installation was a snap, I just pulled the old ones off-You will need a screwdriver to take the door sills off, there is a cover on them you have to pop off to expose the screws. Then I just fitted the new ones on. I was told about drilling holes, and cutting the new ones, but I didnt see any need to drill anything, and they fit snuggly enough and fit the dimensions perfectly. Ive had them on now for about a month and havent had any problems.
When I first put them on, the door didnt shut as well all the time(the door popped open if you closed it too lightly), but after getting worked in a little, they work fine. Guess they just needed some breaking in. I dont hear any wind noise now.
Thanks for the part #'s, i still havent had a chance to diagnose my limp home problem....and we are on our way to Houston again this weekend. We are going to chance it in our ML, its so nice on those long drives, and my C-class is just too small although it runs like it only has 5K miles! I have faith in my ML....and this time, we arent going to stop till we get to the in-laws.
If I ever get around to setting some time aside, I will let everyone know about this shift recognition switch. I have noticed that the shifts are not smooth under heavy acceleration, so I need to get it fixed soon, but like everyone else, I fear the costs!!!

Thanks for the info.

Gilly · #11 05-09-2002, 03:23 PM

It's the range recogition switch. I am not sure that this part would have an effect on shift quality though.
Gilly

1994C220 · #12 05-16-2002, 05:45 PM

Sorry I am just now posting, but I havent had alot of free time this week. I took my ML320 to Houston last week, and it drove wonderfully all weekend while in Houston...Then, Sunday night, on the way home, about 30 min outside of Austin, I noticed that the check engine light had come on...As you know from my previous post, this is what happened the last time- right before it went into the limp-home mode. This time, it didnt slip into the limp home mode, and I have driven it once since I got back, and it seems ok(other than the touchy shifting I mentioned in previous posts). I havent had a chance to check the fuses again, as I did before, but does anyone have any other suggestions? Im almost afraid to drive it anymore. Its a shame that such a nice ride has to sit in my garage.

I know the best thing is to take it in and have it diagnosed by MB, but is there any other way to check the error codes? I know that I was able to get the codes from my C220 by using the climate control LCD...is there a way to get them on the ML320?

Thanks,

Carlos

1994C220 · #13 06-10-2002, 05:49 PM

Ok...I finally broke down and took my ML to the shop. I got a call a few minutes ago from the technician saying that they had narrowed the problem down to two things....

The Actuator motor switch(for the 4 wheel drive),

Or

The Air mass flow sensor. He said it was running rich..

So what does this mean? Is this going to be an expensive visit? He said that they wanted to check into it a little more before they made any changes. And of course it didnt do anything when they drove it...although it was in limp mode when I started to the shop this morning!

Any help or pricing would be tremendously appreciated.

Thanks,

carlos

Gilly · #14 06-10-2002, 11:11 PM

The low range motor i believe CAN put the transmission into limp-home mode.
The MAF sensor won't, but it can cause driveability problems and a "check engine" light.
Gilly

1994C220 · #15 06-11-2002, 11:34 AM

Well, I got the pricing on the gear recognition switch...its 166.00, and he said that he didnt know how much labor would be yet.

The air mass sensor/meter is 250.00, and he said that would be a snap to put in. Im wondering if I might be able to do this myself? Or does it need to be calibrated????

Either way, it looks like other than those two things, he said my ML was in excellent shape. Glad that it wasnt a major transmission problem.

Thanks for your help Gilly....It seems that they didnt look at the gear switch until I mentioned it to them yesterday....they said you did a great job diagnosing it without the presence of even seeing the ML in action.

Thanks again.

Carlos