E420 Transmission Control Problems - Page 2 - PeachParts Mercedes-Benz Forum

HerbPhillips · #16 11-29-2005, 12:00 AM

Are there imposters?

ace · #17 11-29-2005, 07:56 PM

Today I had the error codes cleared by the friendly folks at "All Foreign Auto" in San Jose. They have a Snap-On scanner with an MB module. After resetting the codes, the 12 V appeared on pin 38 of my TCM and , my car is shifting like a dream.

I had re-set codes multiple times using my own generic ISO Scantool but that did not do the trick.
Thanks to all that have contributed, especially to C32AMG even though he wanted me to take my transmission apart, and to HerbPhilips who in the end provided the clue that lead to the solution.
Quite a few lessons learned here.

HerbPhillips · #18 11-30-2005, 04:18 PM

Glad it worked.

I'm also working on a 1997 E420 722.6 right now.

Mine has a very flared, delayed shift in all gears. Has firm engagement, but is chirps the tires in 3-5 gears, and it sets off the ESP.

Took off the pan, orig fluid was beautiful, no particles whatsoever.

From my digging I found this modulator pressure control spring for the valve body.

http://www.transmissionspecialty.com/parts/parts/68942-01.htm

The spring was a few bucks (less than $5) , and I'm going to try to install it tonight. I'm hoping that this will prevent me from buying a new valve body, conductor plate, and tcm...

Mercedes doesn't offer this spring (that I am aware of ).

Auzivision · #19 06-04-2007, 04:00 PM

I have a 2000 e430 (non 4-matic) and experienced a strange thing the other day. Sitting a light, when it turned green and I gave it gas and it felt like the parking brake was on. It would go, but the RPM were high and the engine appeared to be struggling. I notice the CE light, but no malfunctions listed in the information display menu. After reading this thread it appears to be stuck in the limp home mode.

Everything was working beautifully before, so I’m hoping it’s not catastrophic. Are than any typical or common problems that may cause this? I didn’t spill a drink down the shifter. It appears that there is now way to reset this at home, so I’m taking to a non-dealer mechanic who works on Mercedes.

HerbPhillips · #20 06-04-2007, 04:06 PM

The 1st thing I would check are your tire pressures.(sounds strange, I know) , the ASR system sometimes will error out if your pressures are way off and then they subsequently will disable the throttle and won't allow you to go more than 20mph. When this occurs, your rpm's will race, but the car simply won't do anything....Other than 10-20 mph.

Check the wheels, tires, pressures etc. And then cycle the key. Worked for me on a 600SEL last week that I was sure had throttle problems, turned out the tires were overinflated to 50psi.

If the tranny goes into limp mode, it will only operate in 3rd gear (but ultimately you could reach a speed of 50mph).

gmercoleza · #21 06-04-2007, 04:17 PM

I'm just inserting these keywords: W210, transmission, flaring, slipping, module, service, limp, code

I just bought a 1997 E320 and who knows, this might come in handy some day. These electronic transmissions scare me.

Can anyone confirm that I have a 722.6?

suginami · #22 06-04-2007, 05:25 PM

Quote:

Originally Posted by gmercoleza

Can anyone confirm that I have a 722.6?

You do.

gmercoleza · #23 06-04-2007, 05:39 PM

Quote:

Originally Posted by suginami

You do.

Thanks - that's what I thought.

suginami · #24 06-04-2007, 05:48 PM

I'd like to point out that even though early versions of the 722.6 had teething problems and experienced many updates, 2000 and newer are said to be bullet proof.

My neighbor, who is a technician at the local Mercedes dealer, tells me that he never sees a 722.6 come in with problems.

It is also interesting to note that the 722.6 is massively overbuilt for our application (E320 and E430).

The very same 722.6 is also used in the E55 AMG and the SLR McLaren supercar, so it can handle massive amounts of torque and hp.

matttttttt · #25 11-09-2007, 12:45 PM

Hi all,

Yesterday my wife told me our 1999 C230 with 60K has a check engine light came on. The car had a fluid change 4 months ago. She got the code pulled and it was P0720. Talked to my friend at the Mercedes shop and he told me it is weird that only this code came up without others. Anyhow, my wife told me it still drived fine and she had the Shucks cleared the code. I drove it this morning, but not CEL. My question is, why my c230 didn't go into limp-home mode? Could it be just a sensor malfunction? Also where is the TCM in my car? I checked the box
on the passenger side, close to the air intake under the windshield. I don't see TCM printed on top of the box. I want to check to see if there is fluid in the TCM.

Best Regards,

David

HerbPhillips · #26 11-09-2007, 12:48 PM

if it aint broke...don't fix it...

I wouldn't worry about it. If you don't have a shift problem don't go looking for trouble.

matttttttt · #27 11-09-2007, 12:55 PM

It is better to find out now than later. Please help if you can.

Thanks!

BrabusCLK · #28 03-15-2008, 02:16 AM

Can anyone tell me what the part number is on my Automatic Transmission Selector box is (the one the shifter is connected to like a shift gate)? it's the regular one without the tiptronic/touch shift. Also, is there another class/model that has the same part other than a CLK? There is a clean 1999 e320 that someone is parting out because they wrecked the front of it and I was hoping I can make a bid on the box to replace mine that was damaged by my 8 year old child that tried to shift it out of park while it was parked and not running. this bent the bar and while trying to bend it back, cracked the switch for the reverse lights and misaligned it with the space where it should be. the actual D now is accessed if you put the **** lever in between N and D, by the curve to 4. the car runs fine, sometimes is delayed in shifting for 2nd to 3rd, but that is intermittent and very rare.

Icucme4 · #29 09-27-2013, 03:25 AM

Quote:

Originally Posted by ace

Thanks C32AMG.

You are correct about the o-rings, I have replaced those and so far the leaking seems to have stopped. I guess time will tell though.

I do not have the print out you are referring to and I do not know how I could get the read-out of the adaption values.
At this point it is hard to determine wheter the transmission is slipping or not , since it is not shifting. When I put it the selector in R it will go in reverse, P for park and N for neutral but regardless of whether I put it in 1,2,3,4 or D , the only forward gear it will go in to is 2nd gear. It does not shift up to 3rd, 4th or 5th, nor does it shift into 1st when I switch from the W to the S program. As long as it is in 2nd gear, it does not appear to be slipping but off-course it is most likely to slip in between gear-shifts, not when a gear is solidly engaged.

Here is the scenario. I disconnect the battery and/or I clear codes using my scantool (here is the link in case you are interested http://www.scantool.net/products/elmscan_iso.htm )
I start up the car, Check Enigne light will go off.
Now I would expect to see around 12 Volts when I measure on pin 38 of the TCM. Pin 38 is supposedly the common supply voltage for the solenoids (see attached schem1, wherein N15/3 is the connector on the TCM) but there is no voltage there.

This is what makes me think the TCM is not working right. At that point, I haven't put the car in drive or reverse yet, much less driven it since doing the reset. Even if there was something wrong with the Transmission (worn out or whatever) the TCM would not know it yet, at least that what I think.
Anyway , then I put the car in reverse or drive and immediately I can tell that it is shifting harsh. ( the remark about the TCM commanding maximum line pressure from your earlier post may support that).

I had the TCM rebuilt by autocraftdirect. I assumed it was bad because:

1- it had been full of oil, and I figured that metallic particles suspended in the oil could have shorted out a component.
2- I got a host of codes indicating problems with the solenoid valves. It seemed unlikely that all solenoids went bad at the same time, in addition, I measured the resistance of the solenoids and they are all in spec.
3-according to a troubleshooting chart I have, with the ignition on , pin 38 must carry 12 volts.

Now that I received it back from autocraft, the 12V is still missing. I called them , they really don't seem all that knowledgeable. They claim the TCM only provides ground, but that is not what the schematic indicates. They also could not tell me exactly which components they had replaced . I am wondering if they just replaced some of the most likely failing components of the board on the assumption that those would be the culprit.

So, my suspicion is that either :
-the TCM is still defective
-or somehow the limp mode is never cleared (does removing the battery clear the limp mode or is there some sort of non volatile memory that stores the codes and error conditions in spite of removing the power to the electronics?)
-or the limp mode is re-enabled as soon as I start up the car because there is some hard failure in the transmission.( this last option seems unplausible to me since as I said the 12 v are missing before I even take it out of Park).
-Can anyone confirm if the 12 v is supposed to come on to pin 38 as soon as ignition is turned on?

I have this problem happens intermittently and my tranny slips then won't shift at all - Have replaced TCM 3 times each time runs for 3 days to a week then electrical solenoid codes pop up - changed valve body 3 times, conductor plate 3 times, all the solenoids, and finally the wire harness from tranny to tcm and it worked for 2 weeks then after an hour in the car bam started slipping again. I suspect a relay that causes a surge in the tcm or a bad ground I need help any ideas? Almost ready to push it off a cliff lol