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 > Mercedes-Benz SL Discussion Forum

Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 11-25-2007, 05:50 PM
Registered User
 
Join Date: Nov 2007
Posts: 3
ASR on 1991 500SL

Hello to all

Has anyone been able to defeat the ASR system. My ASR light on the dash keeps coming on and car going into Limp Home mode.

Gordan53
Reply With Quote
  #2  
Old 11-25-2007, 11:15 PM
Registered User
 
Join Date: Mar 2003
Location: Milwaukee Wisconsin
Posts: 1,150
ASR is one of the most discussed topics on the forum. Use the search tool.
I found this thread by searching ASR 129. It discusses disconnection of the ASR. Good Luck.
1991 500SL ASR light, disable traction control
__________________
Resistance is Futile.
Reply With Quote
  #3  
Old 11-26-2007, 05:38 AM
Registered User
 
Join Date: May 2001
Location: Las Vegas, Atlanta
Posts: 669
If the ASR malfunction lamp is on but the lamp for ABS is not, then I believe LH Mode is caused by a malfunction in the Electronic Accelerator (EA). In this situation LH Mode can occur with the key on and the engine off, and you can tell that it has occurred by looking at the throttle linkage with the air cleaner housing removed.

The EA controller gets throttle position feedback from a potetiometer in the throttle actuator. If this signal fails to verify that the throttle position is following the command from the controller to the actuator, then the electronic control is disabled and the throttle goes to LH Mode.

If the EA is your problem, then you can restore normal power with a simple modification to the throttle linkage. Refer to the attached diagram.

The rod #97 rotates to move the plate in the throttle body (picture). Normally #97 moves by the throttle actuator and rod #109. But in LH Mode the actuator is dead, and #97 moves through an arm that engages it at its back end (circled). With the air cleaner assembly removed and the throttle closed, in LH mode you can see that as the gas pedal is pressed the arm has to move through a gap before it begins to rotate #97. You can eliminate this slop by wedging a rubber hose or something else into the gap. Another option which I prefer is to change the length of one of the rods in the linkage (I think it is #88) to reposition the arm and eliminate the gap.

ASR can be disabled by interrupting the engine-running signal input to the ASR control module. This is how Renntech does it and is also how it is done in most if not all of the threads in the forums.

On a car with CIS fuel injection the engine-running signal is the blue/white wire to terminal #15 of the ASR module electrical connector. If ASR is disabled in this manner, then the malfunction lamps for ABS and ASR in the instrument cluster are on all the time. To disable those, you interrupt wires to terminals #17 and #29. If no switch is being used to disable the ASR and it is instead off all the time, then you would also probably want to disable the "!" indicator in the speedometer. To do that you interrupt wire #15.
Attached Thumbnails
ASR on 1991 500SL-500sl-throttle.jpg  
Reply With Quote
  #4  
Old 11-26-2007, 08:32 AM
Jim's500E's Avatar
Large Member
 
Join Date: Mar 2001
Location: Manchester, Connecticut
Posts: 1,325
Yes, defeating the ASR will not make your LH mode go away, you could just un-plug a speed sensor to defeat btw....take a look at your engine wiring; both upper and lower harnesses. If you peel apart some of the wrapped wires, the insulation may be all gone and is time to remove that vital part of the system from the diagnosis with a new set. Not exactly cheap...but the new wires are much better made now as opposed to OE from 1991. A very common problem on this vintage MB motor too.

Your LH problem may even be as simple as the $25 brake light switch under the pedal also. Having the code(s) pulled MAY find where the problem is, but it also may not. BTDT on M119s.

Could def. also be the EA... big bucks; $1100+ ...but I think Beckmann is re-building them now for much cheaper than new ones if it is that unit. Good luck...hope it's simple !

...and take a look at the nuetral-lockout switch too !
__________________
Jim

1992 500E
2007 CLK63
2003 Audi RS6
2001 Audi allroad
Reply With Quote
  #5  
Old 11-26-2007, 09:17 AM
Moderator
 
Join Date: Mar 1999
Location: Tucker, Ga USA
Posts: 12,153
Those are all good suggestions for a 1993 & later SL but not applicable for the 1991 version.

NO ASR OR EA diagnostic capabilities on that car! ONLY a pin by pin test when the problem is happening.
__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator
Reply With Quote
  #6  
Old 11-26-2007, 09:45 AM
Jim's500E's Avatar
Large Member
 
Join Date: Mar 2001
Location: Manchester, Connecticut
Posts: 1,325
Really ?....Is my 1992 500E's motor different than the 1991 SL s M119?
__________________
Jim

1992 500E
2007 CLK63
2003 Audi RS6
2001 Audi allroad
Reply With Quote
  #7  
Old 11-26-2007, 10:19 AM
Moderator
 
Join Date: Mar 1999
Location: Tucker, Ga USA
Posts: 12,153
yes, the 1990-92 SL's used CIS injection & the M119 engine was a WIDE block with the designation of 119.960..Almost no interchangable parts between the engines.
__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator
Reply With Quote
  #8  
Old 11-26-2007, 10:27 AM
Jim's500E's Avatar
Large Member
 
Join Date: Mar 2001
Location: Manchester, Connecticut
Posts: 1,325
I see...so the brake lamp switch, neutral-lock-out and TBAs are also different? And the early SLs with M119 didn't get the bio-degradable wiring harnesses either?

Please disregard what I said then Gordon.
__________________
Jim

1992 500E
2007 CLK63
2003 Audi RS6
2001 Audi allroad
Reply With Quote
  #9  
Old 11-26-2007, 12:25 PM
Moderator
 
Join Date: Mar 1999
Location: Tucker, Ga USA
Posts: 12,153
Brake lamp switch is the same..but not much else. No bio-deg wiring on CIS-E engines.
__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator
Reply With Quote
  #10  
Old 11-26-2007, 05:41 PM
Registered User
 
Join Date: Nov 2007
Posts: 3
Thanks guys for your responses.

I have checked the wiring loom and find they are as good as the day they left the factory. They are not bio-degradable.

tecqboy - Thanks for the link.

bobterry99 - I have taken up the slack in the linkages as suggested in your response and e-mail and to my delight the problem is RESOVLED with car driving as it should without LH mode.

Once again guys, THANKS.

Gordan
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 06:08 AM.


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