lost speedo& 2,3&4th gears,have dtc,s - PeachParts Mercedes-Benz Forum

#1 09-24-2002, 08:45 PM

1997 S420 - ASR,ABS,Brake pad wear lamp,Brake fluid level lamps all on. Lost speedo fuel economy gauge and trans wont shift into 2,3 or 4 th gears.I obtained DTCs as follows:
engine:
105 - data link connector
141-o2 bank 1 sencor 2
720- output speed sencor circuit
1605- body acceleration sencor
600- serial link
traction control :
can-traction system communication faulty
can-altitude correction factor from me
can- esp distorted

I checked battery and altinator voltage,good.I pulled the plugs on the wheel speed senders and checked with ohm meter.3 @ 1700 1@ 1800 ohms.
I think the computer is not sending a speed message to the trans,the speedo or the brake system.
Where do I go from here?

David C Klasse · #2 09-24-2002, 09:41 PM

Damn!! That sounds like a big mess! I can't help you, but I can help to help you.....

List the model & year of your Mercedes!

I wish you GREAT luck in solving your problem!

joe p · #3 09-25-2002, 12:16 PM

First things first, clear all the codes and drive it about 2 miles then proceed.

105 - data link connector

ignore this one for now

141-o2 bank 1 sencor 2

ignore this one right now too

720- output speed sencor circuit

run the test for the conductor plate in the tranny, this is done is actual values with the sds or compatable scan tool. If the sensors read way out or fixed, clear the code and retest, still out> replace the conductor plate.

1605- body acceleration sencor

clear it and see, this sensor is used inconjuction with the tranny turbine speed sensors for ASR/ESP.

600- serial link

Ignore this one for now

traction control :
can-traction system communication faulty
can-altitude correction factor from me
can- esp distorted

I'd put this one down to the speed sensors in the tranny "freaking out" which sends the ASR computer into limp home.

I'm thinking that the conductor plate is history however, the is a outside chance that the trannys inputshft bushings are gone allowing the turbine exicter ring on the drum to move away from the "sight hole" in the case. This is easy to check with the valvebody off, look through the bigger holes and see if the rings are fairly centered, if so, try GENTLY moving them away from the holes with a skrewdriver. If they move some but not a lot (1/2" is a lot) it should be fine.

There have been about a dozen updates on the .6 tranny for various reasons one of which being a bronze bushing in the input shaft failing, which allows the drums to walk away from the speed sensor sight holes. I've replace a lot more conductor plates than trannys for this problem. Check those sensors.

Joe

pentoman · #4 09-25-2002, 07:32 PM

David - he did, 1997 S420

I often miss it too..

David C Klasse · #5 09-25-2002, 07:50 PM

Russ,
Believe that, he sure did!

(but this was AFTER my 'reminder')

#6 09-26-2002, 09:26 PM

Thanks Joe, is there an option to using an SDS.What is it anyway?I am still triing to determine where the conductor plate is.Can it be accessed from under the pan.I apriciate the help and input from every one.Thanks again.Cliff

joe p · #7 09-27-2002, 02:35 PM

the conductor plate lives on top of the valve body. you'll have to drop the valve body to get at it. Once its off it pretty self explanitory from there. (it only goes on 1 way) However the connector is another matter, you've got to remove the plug and remove the center bolt from it to get the thing off. replace the 2 orings on it too. the baum iscan will pull the codes from etc.6 but, the definitions are wrong.

Joe