baboli

Hi all,
I started having a problem with my transmission for the past two days.

Sometimes when I'm coming to a slow down or a stop, I feel the tranny jerk to a the higher gear a little late. After this, the transmission is stuck in 2nd or 3rd gear and I cannot use my tiptronic shifter to change it. The display reads D but you can tell it's stuck in 2nd or 3rd gear because it crawls at take off and then just keeps reeving indefinitely.

What fixes this every time is turn off the ignition and start it again. Then everything is fine.

I have an appointment with my mechanic to check with computer. He is an x-mb head mechanic.
I appreciate any help,
Thanks.

SPIKES

i was just going to do a search....mine did that tonight for the 2nd time since i have had the car in 3 weeks.

first i was idling at a stop....in d no gears....move the shifter and a clunk as it shifted...pulled off and would not change gears....sounded like it stayed in first and would not shift...display reads "D". stopped switched off car..back to normal

SZMB

Some people have reported similar problem could be caused by a faulty solenoid in the valve body. Have your mechanic get the code read.

baboli

Someone in another forum had the exact problem and his mechanic changed the "Speed Sensor" but he never posted the result of the fix.
I am taking my car to mechanic this Saturday and see what he says. I was going to change the tranny oil but will hold off until his diagnosis. I will post the outcome.

SZMB

Dirty tranny fluid wouldn't cause the problem you're reporting. Faulty speed sensor wouldn't cause it to be stuck at 3rd gear. My other guess is an electrical issue, e.g. a relay got stuck but resets when you restart the car, and that leads me to believe a faulty gear/shift selector switch. Your mechanic should be able to locate this switch and check it out.

Racin_fool

Most issues inside the transmission will result in the CEL being turned on because of a fault in the transmission control unit (valve body). If you are having these issues, I would have them check the fault codes if there are any, check for any updated software for the engine control unit and transmission, or lastly you could have them try to re-adapt the transmission upshifts and downshifts and see if that helps.

violato

holy ****.. i'm about to start a new thread about this. I just start experience this phenomenon 2 days ago and today. When I'm on highway, it seems to stuck at 7th gear at all times so when it slows down, it will take forever to speed up.

Once it stops, it seems to stuck at 2nd or 3rd gear. It will crawl up slowly and rev up indefinitely. And again, the only way to fix it is by turning the car off and on again.

I will take my car to my mechanic tomorrow and he will scan any faulty codes. I will give you guys an update tomorrow.

violato

UPDATE: I just get back from my mechanic. there are several faulty codes in the transmission control unit, but the 3 most recent one is the speed sensor issue (not sending signal to the TCU). my mechanic clear out all the fault codes and he told me if it's happening again, then bring the car in and have it rescanned just to be sure it's the speed sensor.

SPIKES

mine is going in on tuesday....did you get a fault code (cel) come up on your instrument display?

violato

@Spikes: no, you need to use a special device attached to the area under the driver side

SZMB

Thanks for the update. This is another bizzare electrical oddity in MB engineering. Clearing up the codes without finding a faulty part fixes the problem seems very strange, but then again, MBs are well known for bizarre electrical problems. Normally the ABS warning light lights up when the speed sensor is faulty and disables the ABS function and traction control, but the car still drives normally. A fault in the speed sensor disables the transmission seems odd to me, maybe it's an electrical bug that MB engineers haven't found. If the speed sensor is indeed faulty, the fault code normally cannot be cleared until the bad sensor is replaced. Whatever trips that speed sensor still remains a mystery.

violato

my mechanic says when the speed sensor intermittently failed... the car goes to "limp mode" which prevent further damage to the car and I think the speed sensor is working again after you restart the car... not sure.. that's why he clears the code and when it's happening again, then check the fault code one more time to be sure...

http://wiki.answers.com/Q/What_is_a_limp_mode

SPIKES

thanks....i am hopefull that my car has stored some codes.....will report back..

SPIKES

got a call from mb today....it is the control module in the transmission.
they have to drop the pan and replace it.

baboli

Hi,
Just an update, I changed the transmission oil hoping that would fix the problem but no luck there, right after driving outta shop it happened (after a week of working fine).
So I took it to the x-mb dealer head mechanic and he checked the car with his computer (I have to get that software) and told me 'something' has to be replaced in the transmission, cost about 400USD.
He is ordering the part this week, but maybe puts it in next week. I will post update.
Vahid.

SZMB

Which part is he replacing? The transmission control module? He should have read the code before changing the fluid. I think he can reuse this expensive MB fluid.

SPIKES

mine is back....feels like a new car

replaced speed sensor. fault code 0717, 0718?
software update
replaced control valve body.

hope this helps someone

baboli

The MB mechanic is different than my mechanic who changed the transmission fluid. He also said that the fluid was clean and can be used again.
The MB mechanic did not tell the fault code and didn't tell me what is wrong but he is ordering the part for me.
I will eventually know what is being done on my car. So far I have not paid anything to anyone.

desertw210

Had the same issues over the past couple of days. I just bought my E320 two weeks ago with 94k. Put about 1k miles on it and noticed one morning when I got to work the trans wouldn't engage reverse, tried drive and no luck. Shut it down and restarted, no problem. Yesterday it would lag from a stop and slam into second. On the highway, found it wouldn't come out of 3rd. Same deal, turned it off and restarted and no problem, though had an engine light on. Ran the code with my code reader and got a trans input shaft speed sensor.

SZMB, you're referring to an ABS speed sensor. The one usually mounted on the bearing carrier somewhere that reads the pulses in the cog on the axle shaft. The one we're referring to is internally mounted in/on the trans.

I'm a technician for Bentley/ Rolls-Royce here in Dallas and work in the MB shop. Brought the issue up with my MB tech next to me and he threw out a couple of causes and noted the W210 trans is a pretty bullet proof system. The valve bodies are not solenoid controlled, just a plate. So there's more he wanted to check out. I didn't have time to have it checked Friday, so Monday I'll bring it in after work and have the codes run and get a diagnosis. I'll update then with the fix and ease of repair for those DYIer's!

desertw210

Just realized I was in the 211 section. Sorry..

baboli

I think this type of problem with tranny is pretty common. My trouble code is P0715 and I will have the speed sensor replaced this Tuesday.

violato

please post an update after you replace the speed sensor. I didn't encounter the limp mode anymore since the last time I check for the faulty code, been 2 weeks... weird.. but I'm not complaining

baboli

Apparently that did it! The speed sensor was replace on Tuesday and I haven't had any problem yet. I recommend this mechanic, he seem to know his stuff. His name is Danny and his shop is in Linden, NJ (908-925-6100).
I paid less than $400.

violato

do you happen to have the part number for the speed sensor? (if possible with the price as a reference) i called my MB dealer, and they told me, I have to replace the whole valve body which is BS I believe..

bobora

I had this same problem recently. After haveing this issue happen 3 times to me the cel never came on. They did find a fault code for the tranny stored. I had it fixed under warranty. It was a speed sensor issue but was told they have to replace the whole valve body. Was also told valve bodies are held under lock and key in germany. After fix and software upgrade tranny starts in first gear always when in sport mode. Before it would sart off in 2nd when cold.