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 > Tech Help

LinkBack Thread Tools Display Modes
Old 02-26-2007, 10:41 AM
Registered User
Join Date: Feb 2006
Posts: 27
Unhappy 4-Matic Light On (1992 300E) How to Reset?

I have a 1992 300E 4-Matic. The 4-Matic warning light came on about a month ago and I took it to the dealer who 'reset' it for about $150. Well, the light just came on again, disabling the 4-wheel drive system (which is unfortunate given that I'm driving in upstate NY with snow all over the place). Is there a way for me to reset the system... is there a tool I can buy to do it? Also, any guesses as to what the problem is? I know the transfer case was replaced on the car at about 110K miles. The car now has about 220K on it. Any particular issue I should have a mechanic look at?

Thanks for any help!

Reply With Quote
Old 02-26-2007, 05:16 PM
Registered User
Join Date: Jul 2005
Location: Seattle, WA
Posts: 583
do you have same size/brand/model tires on all four corners?
-- raymond~
47 34'N 122 18'W
Reply With Quote
Old 02-26-2007, 09:49 PM
Registered User
Join Date: Dec 2001
Location: Wilkes-Barre, PA
Posts: 131
Easiest reset is to disconnect the battery for about 10-15 seconds. Troubleshooting is another matter. What are the symptoms? After resetting, does the light come back on immediately?
07 E350 4Matic wagon, 06 S430 4Matic, 02 E320 4matic, 01 E320 4Matic Wagon, 99 SLK 230
01 E320 Wagon (wrecked PM if you need parts), W210, W124, W126
Reply With Quote
Old 02-27-2007, 09:44 AM
Registered User
Join Date: Feb 2006
Posts: 27
Thanks ratmond and brooktre. I reset the warning light. It's staying off for now. I imagine it will come on in another few weeks... just a guess. It doesn't immediately come on.
Reply With Quote
Old 11-23-2008, 10:08 AM
Registered User
Join Date: Dec 2003
Posts: 51
It seems like I can "re-boot" my 4Matic when the light comes on by disconnecting the neg. battery cable. Why can't you do the same thing by turning the system off with the 4Matic "test" switch in the engine compartment? I don't have a wiring diagram and would like to know if the "test" switch is a simple on/off or something more sophisticated. The 4Matic works fine when the light is off but the light will come on for no apparent reason. Thanks, srharvey
'82 380 SL, 150,000
'83 240D, 250,000
'93 300TE 4Matic 315,000
'04 Lexus
Reply With Quote
Old 11-23-2008, 06:55 PM
Registered User
Join Date: Oct 2004
Posts: 3,508
The test switch simulates the sytem's pressure sensor reading no pressure, which puts the system into default. If the module doesn't read pressure from the sensor then the system doesn't come on line , and it doesn't turn the light off.

90 300TE 4-M
Turbo 103, T3/T04E 50 trim
T04B cover .60 AR
Stage 3 turbine .63 AR
A2W I/C, 40 LB/HR
MS2E, 60-2 Direct Coil Control
3" Exh, AEM W/B O2
Underdrive Alt. and P/S Pulleys,
Vented Rear Discs, .034 Booster.
3.07 diffs 1st Gear Start

90 300CE
Milled & ported head, 10.3:1 compression
197 intake cam w/20 advancer
4 ignition advance
PCS TCM2000, built 722.6
600W networked suction fan
Sportline sway bars
V8 rear subframe, Quaife ATB 3.06 diff
Reply With Quote
Old 11-24-2008, 02:08 PM
Registered User
Join Date: Jun 1999
Location: Albuquerque, NM USA
Posts: 1,946
These lights come on because there is a problem.

The way to "reset" the light is to fix the problem.

The problem is not that the light came on.
Kent Christensen
'07 GL320CDI, '06 SLK350
Reply With Quote
Old 11-24-2008, 06:02 PM
Registered User
Join Date: Dec 2003
Posts: 51
I certainly agree re: the light being an indicator of a problem. Our 4Matic people can not find any problem, the light only comes on once or twice a year, the system has had a considerable amount of work done on it and it works great, (when the light is off). The light will come on while the car is idling, or between ignition on/off, or just driving down the road. At those times a simple "re-boot" seems to re-establish the system, then it will work fine for months. I am considering installing a switch on the neg. battery post, for convenience, when the system defaults.

I would like to know what the disconnecting of the battery does to the system that causes a re-boot or re-establishing.

We live on the east coast but drive this car for a month ski trip to Colorado each winter . If there is a malfunction while driving in poor road conditions I do want a convenient method to put it back in service, hence the switch.

Thanks for your ongoing help. srharvey
Reply With Quote
Old 11-29-2008, 11:22 PM
Registered User
Join Date: Nov 2008
Posts: 4
Wink Switch to Conveniently Reset 1988-1992 4Matics

After a transfer case rebuild to my 1992 300E, my 4Matic Failure Bulb would indicate an error code 10 after variable periods of time. Initially I reset it by disconnecting the battery for several minutes. Then I came across a reference noting that Pin 5 of the capped diagnostic connector behind the battery (actually visible as hole 5, which has a female contact below the black plastic surface of the connector) could be touched to Pin/hole 1 (which is ground) for control of the error codes and resetting the 4Matic system. Upon first encountering an error which turns on the 4Matic Failure Bulb on the instrument cluster, grounding Pin 5 for between 0.5 and 2 seconds will elicit flashing of the 4Matic failure light for the number of flashes at one second intervals corresponding with the type of failure detected. If Pin 5 is then grounded a second time, commencing about one second after "steady state" illumination has returned to the 4Matic Failure Light after a sequence of error flashes has finished, and this second period of grounding is maintained for at least 5-10 seconds, the 4Matic Failure Bulb will go out, and normal function of the 4Matic system will return, until the next occurrence of a detectable error condition. I led a wire from the wire going into Pin 5 of the diagnostic connector back into the passenger compartment, and whenever the 4Matic Failure Bulb came on which it did every few minutes to few days, I could reset it at will while driving. Eventually I discovered that the brake switch half which fed a switching signal to the 4Matic system had partially-conductive debris in it, causing the switch to open gradually, as if it were a potentiometer, rather than a switch. Cleaning out the switch and reassembling it gave me about a year of continuous error-free operation of the 4Matic system.
Reply With Quote
Old 12-07-2008, 08:21 PM
Registered User
Join Date: Dec 2003
Posts: 51
4 Matic light

Thanks for your responses. I have a schematic of a portion of the 4Matic circuititry and find that the test/function switch in the engine compartment only grounds out a circuit to the hydraulic unit and one to the 4Matic relay. It still requires working through the codes and grounding to re-establish the system, if the system is workable. I am still looking for a simple way to interupt the power to the system, much like disconnecting the negative battery cable, that will immediately re-boot the system. I do find one line from the OVPR that feeds power to the 4Matic circuitry, it would seem this might be a likely place to insert a cabin mounted switch for remote re-booting. I'd appreciate any comments.

Many thanks for the responsible responses to this forum, it's an ancillary joy to owning a Mercedes.


'82 380SL
'83 240D
'93 300 TE 4 Matic

Reply With Quote


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 06:34 PM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2020, 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