Limp home mode in E300 (W210) - PeachParts Mercedes-Benz Forum

muleears · #1 04-15-2009, 06:29 AM

Yesterday my E300 (188K mi.) was being "test driven" by a guy looking to buy it. Long story short, the car is now in "limp home mode" and was driven in it for 20+ miles. I've looked but haven't found how to get it out of or reset the limp home mode. The car had to be jumped to get it home. The guy tells me it was stuck in second (LHM) before the jump. I was wondering (hoping) that the jump had something to do with the LHM? How do I get it out so I can see if the tranny is OK or damaged? What causes LHM? There are no check engine lights. Am really hoping this is something simple. Low fluid? bad trans controller (or trans fluid getting into it)? I wasn't in the car when it initiated the LHM, so I don't have many details. How do I test? TIA

KarTek · #2 04-15-2009, 10:31 AM

M-E, in my experience the transmission behavior is related to the limp mode. When my car has set a code in the past, boost was limited or non-existant and if I pushed it hard to go, the tranny would hold a gear all the way up to about 4700 RPM and just sit there not accelerating. It would however, shift if I let off the throttle significantly.

If there is some kind of code, it'll reset itself after 3 successful start/warm up/cool down progressions. I'm surprised there no CEL. Does it light up when you start the car?

As for reseting any codes, you'll need some kind of scanner to read and reset them.

Sorry to hear you're still having problems with this car...

muleears · #3 04-15-2009, 11:21 AM

Yes, no codes and the CEL does light when I start the car. It is very frustrating because after the fitting of the new Engine control unit, it was running beautifuly. And now this. I haven't had a chance to see if any codes are stored. That will have to wait until this afternoon. I'll report what I find. The motor still runs fine and doesn't seem to have limited boost. It is weak up to about 15-20mph then pulls fine, but at about 40-45 the rpms get around 3K and above, so I didn't drive it very fast.

KarTek · #4 04-15-2009, 11:50 AM

Just a thought, check and make sure the MAP line hasn't blown off...

F18 · #5 04-15-2009, 12:02 PM

Muleears.......had the same thing happen to my 98 E300 2 years ago and it turned out to be a bad battery. You said it had to be jumped.......how old is the battery? When the current output drops from the battery weird things start happening on these cars including it going into "limp mode"
Hope that helps

muleears · #6 04-15-2009, 12:16 PM

The battery is kind of old and he did kill it trying to start it with air in the system. If I put a good battery or fully charge the one in it will it come out of LMH?

TMAllison · #7 04-15-2009, 12:24 PM

LHM is going to be 1st, 2nd and R only. Is that what has happened?

About the only trans code tht OBDII will pull up is PO700 or 715; everything else (the codes that are meaningfull) will require SDS or other high end scanner to "see". In addition to the trans codes, those scanners should also be able to read the trans adapation values which will tell the tech how the trans has been internally adjusting itself recently. The two bits of info should provide enough info to figure out whats gone wrong.

Resetting by disconnecting the batt will not usually clear trans codes and only a few codes (PO380 comes to mind) clear themselves after the 3 cold, hot, cold run cycles.

I suppose its possible its due to a low voltage problem but suspect the prob lies elsewhere.

jcyuhn · #8 04-15-2009, 12:48 PM

If it's spinning 3K RPMs @ 45MPH, what gear is it in? It's been too long since I sold my E300, but that doesn't sound right for 2nd, too high a speed. Is the car stuck in 3rd gear?

muleears · #9 04-15-2009, 01:14 PM

I beleive it stays in second gear. I can't tell that it shifts.

TMA- I thought LHM was only second and reverse?

I forgot to mention, moving the shifter does nothing. Only when placed in park or reverse. If it is in any of the other selections three or two for instance it stays the same. I'm not sure but I thought it was about 2800 rpm at 45 mph. Wouldn't that be about right for second?

KarTek · #10 04-15-2009, 03:16 PM

Before you go crazy, take a look at the MAP line - just a hunch. It's easy, just takes a 2 sec look under the hood.

jcyuhn · #11 04-15-2009, 04:52 PM

MB had a rash of trans controller failures on the early 1998 E300s. I had a very early one - it was the MBUSA press loaner car. The trans computer failed around 1.5 years in. In limp mode the w/s switch controlled whether the car was in 1st or 2nd gear. When mine failed I was only a couple of miles from the local dealer, so I flipped it over to the W setting and limped to the dealer. Part of the trip involved driving on a freeway access road with a 50MPH speed limit. I recall not being able to go that fast because I didn't want to rev the engine continuously above 4K RPM.

So if you can manage 45MPH at ~3K RPM, I think you are in 3rd. I do recall reading there are failure modes where the transmission simply stays in the current gear rather than reverting to the 1st/2nd LHM. Unfortunately don't recall any specifics about what can trigger one failure mode vs. the other, if I ever knew.

- JimY

muleears · #12 04-15-2009, 05:17 PM

Update,

I started the car, it did turn a little slow but started ok. Put it in reverse and there was a two second pause before it engaged, backed up to turn it around and put it in drive, went into gear and started in first. Drove a mile or so and it appears to be shifting properly. Went back to the house, put it in park, then shifted to reverse and got immediate engagement, then to drive and immediate again. Left it running and pulled the codes, only P0700 (bullseye TMA) showed up. Cleared the code and came in here to write this. Will go for a few mile drive now and see whats what. Back soon. Thanks to all for the help.

muleears · #13 04-15-2009, 06:11 PM

Drove it about 7 miles. Seems all is well. I'll add to this thread if something else crops up. Thanks for the help. I was really worried there for a while

Diesel911 · #14 04-15-2009, 07:42 PM

Quote:

Originally Posted by muleears

Drove it about 7 miles. Seems all is well. I'll add to this thread if something else crops up. Thanks for the help. I was really worried there for a while

What do you think the origional cause was???