98 ML320 no upshift CODES 41,137 - PeachParts Mercedes-Benz Forum

riske · #1 03-23-2007, 08:41 PM

This is an update to a previous thread which I posted a few days ago. Since then I had the vehicle scanned for codes. Here are the results:

ETC-Electronic transmission control
CODE 41 Fault in CAN communication with control module N78(Transfer case module) or the transfer case position is implausible

CODE 137 A spuradic fault in CAN communication with control module N78(Transfer case module) or the transfer case position is implausible

ME2-SFI Motor electronics 2
CODE PO700-106

VG-Transfer case
P1831 Positioner motor or position sensor or power supply is faulty

This problem is intermittent. Here are the important details:
1. The vehicle shifts from 1st to 2nd but will not up-shift to 3rd gear and beyond.
2. This malfunction occurs intermittently during the course of any given day.
3. Engine temperature seems to have no affect on the problem as it occurs sometimes when the vehicle is stone cold as well as when the vehicle is at optimum operating temp.
4. The problem occurs more often during heavy acceleration than light acceleration, however it has occurred several times under light acceleration.
5. I serviced the transmission, replaced the filter, drained the torque converter, pan, and lines, and re-filled the correct volume of fluid with the correct MB trans fluid. I then re-checked the fluid level with the proper measuring tool. This had little affect as the problem still persists.

The tech who retrieved the codes for me said that I need a new Control module and a new high\low range motor.

I would like a consensus of opinions before I buy and install these parts.
I thought I would try the module first and if that does not solve the problem I would put in the motor.
Correct me if I am wrong but I believe that the module is located under the center console directly behind the shifter and the motor is under the car attached to the transfer case.

Does the system need to be scanned or re-programed after the installation of either of these items?

benztech13 · #2 03-23-2007, 09:04 PM

The transfer case motor's going bad are a common problem. I do not see this being related to your shift complaint but I could be wrong. How often does this occur? Any codes in ME? Does your low range light flash when starting the car?

riske · #3 03-23-2007, 09:40 PM

The shifting problem occurs every day.I can usullly get it to shift after playing with the shifter, re starting the vehicle driving for short distance in 2nd gear stopping and letting the thing ilde for awhile, you name it...I try a lot of things until the thing starts to shift. Once I get it to shift its good for the rest of the day if I dont shut off the engine.

The only code in ME is listed as "ME2-SFI Motor Electronics 2"
it is: CODE PO700-106 Read out fault memory of control unit ETC

Low range light does not flash any time

david s poole · #4 03-24-2007, 10:44 AM

sonds like the shifter recognition switch.did someone spill drink in it a few months ago?

stevebfl · #5 03-24-2007, 10:52 AM

I guess since we are spinning the bottle, I'll stack the deck and say again what I said the first time. Replace the transfer case position motor. But if you really want to evaluate it, pull it off and check out the internal wiring. I have seen a number where the wiring (internal to the component but externally accessible) is rubbed through.

I see no reason to replace the controller till you deal with this code. BTW it is so simple a caveman could do it.

muskratbenz · #6 03-26-2007, 08:20 PM

Previous reply is most likely correct (even if it weren't from Steve Brotherton, who has almost mythical status on several forums). The range recognition sensor (unit inside shifter housing) is frequently misdiagnosed - mostly due to the fact that it is also a part known to fail. I had mine diagnosed as faulty twice, with replacement the recommended procedure. Both times a little luck at some DIY fixed the problem for 0$ in parts cost. Before the range rec. swith is ever replaced, its output can be tested with a $15 multimeter at the trans control unit plug. Takes about 5 minutes.

revan · #7 03-27-2007, 05:48 PM

Replace the transfer case position motor first. Without CAN communication the trans will go into limp home mode with is second gear. This is probably why you are loosing CAN with the transfer case ECU.

riske · #8 03-28-2007, 09:56 PM

Thanks everyone for your imput.I decided to order both parts, the hi low motor, and the module. I tried the module first and it solved the shifting problem and no codes have re appeared after over 100 miles of driving. Low range is still inoperative so I assume that when I replace the high\low motor that malfunction will also be fixed.