Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help




Go Back   PeachParts Mercedes-Benz Forum > Mercedes-Benz Tech Information and Support > ML, GL, G-Wagen, R-Class, Unimog, Sprinter

Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 07-18-2016, 01:00 AM
Registered User
 
Join Date: May 2015
Posts: 22
'98 ML320 won't shift out of 1st gear

Out of the blue our ML320 has decided not to shift out of 1st gear. It will drive around just fine in 1st gear, but we can't go anywhere obviously. The ABS, ETS lights are on.

The code reader showed codes for the brakelight switch, which I replaced today and there are 2 codes related to the rpm sensor:
C1100 Rpm Sensor FL
C1100-016 Rpm Sensor discontinuity

Also, when trying to access the ME2-SF1 Motor Electronics heading on the scanner the tool reads, "Fault in communication with ECU."

When first hooking up the scanner it "hints" at the Electronic Selector Module.

This transmission has always driven great. There are 200K miles on it, but it was always serviced and flushed a year ago, refilling with new fluid. I have a feeling there is something other than the tranny preventing this thing from driving.

Any ideas? Is the Rpm Sensor located within the conductor plate? I know there are 2 sensors inside of the conductor plate, but I don't remember what 2. Maybe transmission speed sensor and Rpm sensor?

Any help would be greatly appreciated. Thank you!
Reply With Quote
  #2  
Old 07-19-2016, 08:03 PM
Registered User
 
Join Date: Jan 2012
Posts: 7,166
Can you get live data through your scan tool? There is a front and rear RPM sensor in the conductor plate so reading that would be helpful.

The 722.6 trans you have actually defaults to 2nd gear so you would be able to get a bit more speed up than just 1st.
Reply With Quote
  #3  
Old 07-25-2016, 11:39 AM
Registered User
 
Join Date: Nov 2010
Location: TX
Posts: 3,606
I have experienced this a few times. The transmission actually stays in first gear in such failure if the mode select switch was left in S. The identifier of this failure is that your gauges will not show the gear position. Its quite odd I know, because the failure is intermittent the TCU does recognize the shifter select once and allows the 1st gear shift to be initialized. Then it goes blind and stops.

This can happen from a very low battery or a faulty gear select lever unit too - In my case the car I was working on was the same as yours and the gear selector was indeed faulty, You need to connect your scan tool and test the EGS module for gear position.

a bit more info is that it showed up on very hot days.
__________________
2012 BMW X5 (Beef + Granite suspension model)

1995 E300D - The original humming machine (consumed by Flood 2017)
2000 E320 - The evolution (consumed by flood 2017)
Reply With Quote
  #4  
Old 07-25-2016, 01:27 PM
dkveuro's Avatar
Sword of Damocles
 
Join Date: Jun 2003
Location: Here an' there.
Posts: 2,548
2nd gear is 'Default" . Does Reverse work ?

A live scan will id a fault but external problems are not unknown. By the front passengers side of the transmission is the TCM to trans' loom of 14(?) wires. They are covered by a small shield as they leave the transmission.

This loom is routed up to the body very close to the primary cat' in the down pipe exhaust. The possibility of this bundle of wires being cooked is very high.

Remove the loom shield and cut away the loom sheath. tease out all the wires and look for insulation melting and deterioration allowing wires to short together.

You can buy a new loom or carefully insulate each wire. If there is a lot of pink ATF leaking from the transmission multi pin plug, there is a kit of parts to reseal it.

There are some 'How To's' on You Tube showing the procedure and eBay etc has Conductor Plates if it turns out the relay board is bad.

I hear some say the ATF can wick into to TCM causing it to fail, but if you think about this for a minute, it seems unlikely. The Conductor Plate relays and sensors in the transmission do fine submerged in ATF and some transmissions have the TCM inside the transmission.




.
__________________
[http://languageandgrammar.com/2008/01/14/youve-got-problems-not-issues/ ]

"A liberal is someone who feels they owe a great debt to their fellow man, which debt he proposes to pay off with your money."
Reply With Quote
  #5  
Old 07-25-2016, 05:12 PM
Registered User
 
Join Date: Jan 2012
Posts: 7,166
Plain oil in the TCU wouldn't be a problem. This issue is graphite from clutches / suspended metal in the oil is conductive and can cause problems at the TCU because much of it runs at very low voltage. Any stray voltage across traces can cause a problem.
Reply With Quote
  #6  
Old 01-24-2017, 10:55 PM
dkveuro's Avatar
Sword of Damocles
 
Join Date: Jun 2003
Location: Here an' there.
Posts: 2,548
So....what the hell was the problem ?



.
__________________
[http://languageandgrammar.com/2008/01/14/youve-got-problems-not-issues/ ]

"A liberal is someone who feels they owe a great debt to their fellow man, which debt he proposes to pay off with your money."
Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On




All times are GMT -4. The time now is 07:25 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2018 Pelican Parts, LLC - Posts may be archived for display on the Peach Parts or Pelican Parts Website -    DMCA Registered Agent Contact Page