97 E300 transmission limp mode - PeachParts Mercedes-Benz Forum

spark3542 · #1 08-08-2009, 01:23 PM

97 E300, 169k miles, 722.6 5 speed transmission.

During a short trip about 25 miles from home, I noticed the car would not shift out of 4th gear. Very slow starts at traffic lights. Made another stop, and when I restarted the engine, I got a CEL and "Engine Electronics'. Car was now stuck in limp mode (2nd gear only).

25 mile trip home in 2nd gear was rather painful, keeping below 30mph to keep the engine below 4k rpm.

ScanGauge at home reported P0715 and P0720. Searching this forum revealed that the most likely culprit was the conductor plate in the transmission.

Drained the fluid...fairly black in color. Replaced conductor plate, spacer, filter, gasket, and added 3.5 liters of MB ATF.

Reset the codes and restarted the motor and drove through all the gears several times...at least half a dozen. Codes continue to return on each restart and vehicle continues to stay in limp mode.

My questions...Have I not restarted enough times to "self reset" the transmission? Will it never "self reset" and I need a tool to reset the tranny codes? Have I, in fact, not fixed the problem? Is there any way to reset this from home? Dealer is 20 miles away, and I never taken any cars to an indy (or a dealer for that matter). 20 miles (again) in 2nd gear is not on my list of things I want to do.

Thanks

Mark

TMAllison · #2 08-08-2009, 03:13 PM

You are seeing generic OBDII codes with your scanner. There should be MB specific trans codes that you cant view as well. They'll need to be read and erased using SDS or another high end scanner before you will know if you fixed the prob or not.

That scanner will also provide live and stored data showing how the trans has been adapting internally attempting to keep shifting smooth and proper; that data (with the codes) is very useful to the tech when diagnosing.

Try finding out if someone closer to home has a scanner capable of reading MB. There are a handful that will.

spark3542 · #3 08-10-2009, 05:09 PM

A couple dumb questions:

What does SDS stand for?

Are the MB specific codes read from the OBDII connector or somewhere else?

I called a local indy and he assures me that he can read the codes. I reiterated that it is not generic OBDII codes, it's MB specific trans codes. He claims he can.

We'll see tomorrow.

TMAllison · #4 08-10-2009, 05:20 PM

SDS = Star Diagnostics System = run on MB dealer laptop.

Usually the better scanners will plug in under the hood.

spark3542 · #5 08-11-2009, 01:33 PM

As I suspected, my indy could not give me any tranny codes, but claims the only codes are the 715 and 720 that I already knew about. He says that it's not the conductor board, but the input turbine sensor that is the problem. He claims the "bad" input turbine sensor is causing the output sensor fault code as well.

I really don't believe him, but it raises a couple more questions:

Is there a separate input turbine sensor, and is it easily changeable?

He claims if the problem is fixed then resetting the code will be successful.

Thanks

mbdoc · #6 08-11-2009, 04:43 PM

Turbine sensors are part of conductor plate.

Your indie in incorrect.
He did not read the trans codes, he did read ODB2 codes that specify trans codes.
Erasing those codes will from the OBD2 will not clear those codes from the trans.

Trans codes are Numeric from 1-192 with codes from 1-96 being hard codes & from 97-192 intermittant.

michakaveli · #7 08-11-2009, 04:49 PM

If you're afraid to go to a stealer, look up Bosch Authorized repair shops tha tare close to you. Call them and ask if they have the STAR Diagnostic system.... MB specialists will have it.

Good Luck! If that's the original trans, sounds like it could be on it' way out...

Kontoboy · #8 08-18-2009, 02:13 AM

Had the same P0715 code on my 1999 ML320 4 Matic 722.5 trans and did the same steps as you up until resetting the transmission adaptive mode. I ran through this sequence before driving:

- Turn the ignition key to the on (not start) position
- Press the gas pedal to the floor and hold for five seconds
- Turn the key to the "off" position (don't remove the key), then release the gas pedal
- Wait at least two minutes for reset

This supposedly resets the trans adaptive settings back to factory settings until your driving habits are re-learned.

I also erased the P0715 code with a generic OBDII reader.

So far we've been driving it daily 2+ weeks with no problems. Still, I ordered and am waiting for a mutliplexer to arrive so I can hook it up an also erase the transmission control module codes. My local Indy would do it for $90, but the mltiplexer was $105 (Dealtime.com) so I made the investment.

Kontoboy

spark3542 · #9 08-18-2009, 11:58 AM

Quote:

Originally Posted by Kontoboy

Had the same P0715 code on my 1999 ML320 4 Matic 722.5 trans and did the same steps as you up until resetting the transmission adaptive mode. I ran through this sequence before driving:

- Turn the ignition key to the on (not start) position
- Press the gas pedal to the floor and hold for five seconds
- Turn the key to the "off" position (don't remove the key), then release the gas pedal
- Wait at least two minutes for reset

This supposedly resets the trans adaptive settings back to factory settings until your driving habits are re-learned.

I also erased the P0715 code with a generic OBDII reader.

So far we've been driving it daily 2+ weeks with no problems. Still, I ordered and am waiting for a mutliplexer to arrive so I can hook it up an also erase the transmission control module codes. My local Indy would do it for $90, but the mltiplexer was $105 (Dealtime.com) so I made the investment.

Kontoboy

This would have been great info two weeks ago!

Update:
The indy that I took it to had no clue about MB tranny codes. He stuck by his claim that I still had a problem because the engine codes kept coming back. He would not admit that he didn't have the right equip and charged me for the diagnostics anyway.

Trailered the vehicle to the dealer. They read the codes, and reset them for 1 hour's labor ($115).

Car drives great now. I'll drive it for a week now to confirm the fix before releasing it to the wife.

Total outlay:
Conductor Plate...$180
MB ATF $15/liter x 4...$60
Filter, spacer, gasket, tax...$64
Indy mis-diagnosis...$65
MB code reset...$115

I'm OK with a $485 tranny fix, and even better if I can reset the tranny codes with the above procedure.

What I don't like is $15 per liter for ATF. Is there a lower-cost alternative?

Thanks for all your help guys. As usual, this forum make potential headaches fairly painless.

TMAllison · #10 08-18-2009, 01:07 PM

Quote:

Originally Posted by spark3542

I'm OK with a $485 tranny fix, and even better if I can reset the tranny codes with the above procedure.

That procedure does not erase codes; it only resets your personal shifting adaptation style back to factory pre-set.

Codes can only be erased by higher end scanners as you did.

nhdoc · #11 08-18-2009, 01:41 PM

If you only used 4L of tranny fluid then you didn't drain the torque convertor and should do so as part of a complete fluid change. There is a total of 7.5L of fluid in the 722.6. FYI, you can use the most recent fluid for the 722.9 which is backward compatible to the 722.6 and it is a little cheaper than the original stuff.

Still you are lucky to have gotten it fixed as cheaply as you did, congrats!