Intermittant ASR problem 1993 500E

ke6dcj · #1 06-11-2002, 02:00 PM

Our 1993 500E (75K miles) has been having the ASR light come on intermittantly and go into LIMP MODE. BTW- the wiring harness replaced at 65K miles.

I only get it during startup (sometimes), and so far only during a cold start or when the car has been sitting for at least 4-hours (condensation or water somewhere?).

Restarting the car, makes it go away, and everthing drives and operates fine.

Since I can't duplicate it at the dealer, is there still codes to pull?

What should be my plan of attack?
Idle control switch (inexpensive)
Tranny neutral safety switch (inexpensive)
throttle actuator slide (ouch!)
Another wiring harness (ouch!)

Something else?

Thanks in advance,
:-) neil
1988 360TE AMG
1993 500E

Mark Stetson · #2 06-11-2002, 02:22 PM

Neil,

Check out the thread named:

1992 500E "ASR/limp home mode" problem continued

Best way to spend your money is on diagnosis. The fault codes are stored. Study the stored codes - maybe you'll find the answer there, as it was, even though it was hidden amongst six or seven error codes, on mine. The problem on mine (and on Guido's) was with the safety neutral/shift position indicator switch. You'll recall that with my car, the tech didn't find it until he called in a consultant who had the ThinkPad-based MB diagnostic unit. It showed the problem live; my car was getting so bad I could pretty much expect it to go into "limp" every time I drove it. But as JimF pointed out, it was hidden in the stored codes as well.

ke6dcj · #3 06-11-2002, 02:59 PM

For posterity sake here's some MB PN#s for ASR associated items:

Idle Switch (MB PN# 140.545.01.14)
Neutral Safey Switch (MB PN# 000.545.62.06)
Throttle Actuator/Slide: 2-versions
000.141.79.25 upto engine:
970 12/52 034113
970 12/52 017117
974 12/52 007765
975 12/52 010028

000.141.94.25 from engine:
970 12/52 034114
971 12/52 017118
974 12/52 007766
975 12/52 010029

Engine Harness for FI & Cam-position:
Upto MY 1992: 124.543.95.26
From MY 1993: 124.440.20.06

:-) neil
1988 360TE AMG
1993 500E

TomE500 · #4 06-11-2002, 03:44 PM

You will need to replace the TBA (Throttle Body Actuator) $540.00 here at MS and $950 ish at MB dealer.

In plain english - there is a potentiometer encased in a circular black housing (circumference of half dollar) on the right side of the Throttle Body. That pot will deteriorate due to heat of engine affecting it. Mine went with only 31K on the clock. Engineer told me it is not a mileage related thing, it is a heat related thing. Mine started intermittant in March 01 to full time by July 01. The engineer said the pot started dying in March and just $hit the bed in July. You have to be a licensed MB part rebuilder to acquire just the potentiometer (cheap sub assembly). The MB engineers that designed the rig realized it was a crap idea because there was no way to heat shield the pot. The 1995 model ASR is totally different( PC card controlled-no pot) and mounted (on the firewall, I think) away from the heat of the engine.

Live with it until it goes full time.

A less expensive solution than my route with the dealership:

Buy the unit here on MS. There are only 4 bolts and a gasket to swap out. When you are finished installing it, "limp" the car to a dealer with full diagnostic computer or independent with an HHT and ask to have the codes cleared. Although it only takes a few minutes to clear codes, you will prolly still be charged for 1 hour work.

(An authorized MB dealer charged me $900 something for the TBA plus 5.5 hours labor totalling $1500 something.)

It takes about 2 minutes to unfasten the air cleaners and ten minutes to unbolt existing TBA. 15 minutes to clean/prep surface for new gasket and 10 minutes to rebolt new TBA, plug in the pot to the harness and remount aircleaners.

ke6dcj · #5 06-11-2002, 06:29 PM

Tom- I'd like to understand your logic as to why it's not the "Neutral switch" or the "idle switch".

Is it because my symptoms are similar? I just hate throwing parts at a problem.

My dealer wants to charge me $60 to pull the current codes. Does that seem reasonable?

BTW- if it is a bad "pot" I wonder if I can source it out . . .

Thanks,
:-) neil

400E · #6 06-11-2002, 07:54 PM

Neil,
FWIW I think $60 for a firm diagnosis is money well spent. I've had intermittant limp home/ASR light problems, mostly in the winter when I've got my snows on, and I think it might be related to a tire size discrepency since it hasn't happened when my "summer" tires are on.

Most recently, however, I had a limp home/ASR light/ABS light condition. My independent tech pulled codes and found it to be a bad brake lamp switch, of all things. If you look at the schematic, the engine computer receives a WIDE variety of inputs, any one of which can throw it off and produce the dreaded limp home/ASR condition, so it MAY not be the TBA (yet -- ).

Steve

Mark Stetson · #7 06-11-2002, 08:16 PM

Neil - I wasted my money on the Throttle Actuator and the EACM - the two big ticket items. Putting those parts in didn't solve my problem. I felt better about replacing the harness, even though that wasn't the problem - it was obviously disintegrating. Read up on JimF's site - he's got a good rundown on the codes. No indy in the SB area that would charge you less for the printout?

TomE500 · #8 06-11-2002, 08:57 PM

Neil You may wanna read the "Evaluating Electronic Engine Controls" material posted here on the DYI String:

http://www.peachparts.com/Wikka/EngineControls

This will give you a general oversight of the codes, how they are stored and how the tech "reads" them.

If you bring your car in now for the tech to read, you will pay $60.00 to see the codes read out for the three items that you posted. It simply means that the on-board computer did not get a definative absolute yet from the sensors throughout the drive train system of the vehicle. In a nutshell: It doesn't know specifically fhat the wuck is wrong yet so it tells the tech to check all three possibilities. The tech will "pull" the harness between the pot and the computer and replace it with one of like kind from a vehicle in the shop similar to yours (91-95 119 engine with ASR) that does not presently show any codes related to the ASR. The tech will take that route first because his training has informed him of the problem with all the harnesses especially that harness because it sits on top of the engine exposed to the most amount of heat and may have deterioated insulation of individual wires hidden by the plastic wrap around the harness. (Note-you said the harness was replaced 10K miles ago-If that harness was also replaced {most likely of all harnesses to fail} I think it would be a safe bet to eliminate that possibility.)

The "Idle control Switch" is also a small pigtail "harness" mounted under the drivers side floor mat. (That is the $41.00 part) My tech replaced that part, cleared the codes, and went about a mile before the "limp mode" re-engaged. Upon returning to the shop, the DTC showed that the brand new one was a possible culprit along with the other two. He was 99% sure at that point that it was the TBA but was reluctant to buy the part only to find out he was 1% wrong and have to eat it. He delivered the vehicle to FMW(authorized MB Dealer) A tech who owns a 500E repeated his initial steps and then replaced the TBA, cleared the codes and the vehicle has operated with no DTCs on ASR related problems since (appx 9 months)

The reason I suggested living with it until it is a full time problem is that it will eventually become just that. If it is the pot, the DTC will point only to that in the code read out. As I said in an earlier post, no one will sell you just the pot and it can not be duplicated to the best of my knowledge. ONLY "authorized" MB rebuilders have access to the components and sub assemblies that make up the "whole" of the TBA. I closely examined the "re-manufactured" TBA that was installed in my vehicle and discerned that the only thing that was replaced was the potentiometer and it's plastic housing. I asked if I could keep the original one and was told I would have to forfeit a $300.00 "core charge" [an eltro-mechanical engineer friend told me that the pot was prolly no more than a $10.00 sub assy]

If you want POM (piece of mind;^), spend the $60.00 bucks. If you are an 8 on the 10 scale of DIY wrenching - DO IT YOURSELF!

Tom

ItalianBenz · #9 06-11-2002, 11:40 PM

[B]Neil, dont go dumping all your change into the EA and throttle actuator.. As mark did I replaced the nuetral safety switch,and also I replaced the brake stop lamp switch. Both of these components store cods in the ASR control unit,and the Elelctronic accelerator. You should run a VMI on your car and see if the throttle actuator has ever been replaced. Chances are I bet it was at one time under warranty. Since Mark and I did ours I have no more ASR intermittents at all. I also repaired an S320 and 400E and a 500E. With the Similiar complaints They have not been back. Rem how much wear these components, the brake stop lamp switch,think how many times you depress that pedal.
Do these first, Also make sure your throttle cable. I had one where the cable was broken on the engine side causing the ASR to go haywire. Neil if you give me your vin I can run a VMI for you or just go to your local cutter motors ask your advisor for a VMI print out from there you can see a hist of **** that was done

guido

ke6dcj · #10 06-12-2002, 12:04 AM

The dealer ran a VMI, and either than regular service, only the wiring harness was done.

They also ran a DTC memory dump and gave me the printout (see below). They also cleared it.

From what I understand, I should replace the brake light switch; and idle switch; and neutral safety switch first. Then maybe the actuator. I'm going from least expensive to most expensive (bypassing the wiring harness since replaced 10K miles ago).

Tom- perhaps you're right about the system just dumping 3 or 4 possible areas to check. . .

The ASR codes *might* be problem, but I have an ASR defeat switch . . .

Is my interpretation correct?

Thanks,
:-) neil
1988 360TE AMG
1993 500E

======================
LH1SFI
MB NUMBER: 014 545 65 32
Diagnostic version 0/02
No fault (DTC) stored
---------------------
DI1
MB Number: 014 545 43 32
Diagnostic Version 0/00
No fault (DTC) stored
----------------------
DM
MB Number: 015 545 13 32
Diagnostic Version 0/02
006 ISC -> EA
----------------------
EA
MB Number: 124 545 45 32
Diagnostic version 0/02
048 Reference potentiometer, potentiometer monitoring M16/1r1
054 EA M16/1 actuator
096 Starter lock-out/back-up lamp switch S16/3
224 CTP (idle) switch S29/3
----------------------
BM
MB number: 011 545 97 32
Diagnostic version 0/00
No fault (DTC) stored
----------------------
ASR
MB number: 013 545 39 32
Diagnostic version 2/01
021 Pressure Switch A7/3s1 Long-term monitoring
030 CAN: No reception from EA/CC/ISC N4/1

==========

TomE500 · #11 06-12-2002, 10:29 AM

http://www.imagestation.com/album/?id=4292428625

Scroll over to the right side of the screen when you find what you are looking for. You will see: "test step/remedy". If you are a 10 on the 10 scale using electronics, you can interface the on-board computer using a multimeter (Lucas or Lambda) to read the codes.

You can even clear the codes using the ignition on/off sequence in the remedy section and a couple of wires to ground out and erase the codes.

Now that I have you fotally contused, forget the whole idea. You said that you have an ASR defeat so when/if you go into "Limp D Mode" kick on your ASR defeat and continue on your way in a more "spirited driving" mode.

When the intermittent becomes always you will know that you are there because your "check engine" led will come on. When it does, check your oil pressure gage at 1500 rpms - should be "3". and coolant temp gage. If both in normal operating range, ignore ce led. This is when you will wanna clear all stored codes including the ce and restart engine. shut engine off and read the code. Whatever is in there should be the culprit and it should be down to one code by that time.

Tom

#12 06-12-2002, 07:08 PM

Here is a thread re fix of ASR on my 94 600SL, where culprit was switch under accelerator pedal. Stop lamp switch was also a fault code, but didnt solve problem, nor did two new throlltlw actuators.

Thread

Robert Nelson
Junior Member

Registered: May 2002
Location:
Posts: 3
600SL ASR Problem
I have reviewed a couple good threads here re similar problem, that is intermittent ASR and limp-home mode, in this case in my 1994 600SL. Here an independent mech 1st pulled only DTC 030. On reset, worked for 24 hours, then steadily became more frequent. Local dealer says DTC 030 plus 224 NEA. I cant find anything re DTC 224. Anyway, I pick up car tonight from dealer with two new throttle actuators. I am told to drive for a week to see if problem fixed - if not, no charge for throtle actuators. Does this make sense? I doubt this dealer did any of the tests I see discussed at ALLDATADIY.com.
Any suggestions?

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05-14-2002 04:45 PM

Robert Nelson
Junior Member

Registered: May 2002
Location:
Posts: 3
Picked up car at 5:30 with $5600 worth of new throttle actuators.
Did not make it 20 ft before ASR light and limp home kicked in. Poor service manager is probably drinking heavily this evening. Exact same DTC's of 030 and 224. After replacing actuators, dealer drove for 20 miles with no problem, but I couldnt get 20 feet. I never could understand how two actuators would suddenly develop intermittent failures. Sounds like wiring glitch to me. Sent dealer a service bulletin I found on- line re shift lever switch, mentioned alternator, battery, voltage, harness issues, and mentioned this appears to be a cold engine issue, also, but I get the feeling the service people are not much interested in my suspicions. From the threads I have found here, sounds like all I can do is be patient, and hope OJ finds the real killer.

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05-14-2002 06:52 PM

arif
Member

Registered: Apr 2002
Location: Los Angeles
Posts: 41
had the same problem with my 500sel. after new throttle actuator...no change...turned out to be $5 selector switch under transmission. suggest you do a search and look up many other threads on ASR problems.

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1993 500SEL

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05-14-2002 07:02 PM

gillybenztech
Moderator

Registered: Mar 2001
Location: Abrasive since 1961
Posts: 1334
I'm not sure about this switch under the selector, but I do believe there is a microswitch in the throttle pedal itself (inside the car) which can give a false reading and put the throttles into limp-home. It could also be a problem with the EA control module itself. Theres a few other things that could throw this into limp-home, if I were working on it i would hook up the HHT and monitor the actual values of the CTP switch. I wouldn't bother with the 20 mile roadtests (as much as I love hearing the M120 purr), instead I would do what you did, drive around the lot 20 or so feet at a time, then stop, 20 more feet, etc. Yes, "both throttle motors" didn't sound right to me either.
Gilly

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Mercedes-Benz Master Technician
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05-14-2002 08:38 PM

Kebowers
Senior Member

Registered: Jul 2000
Location:
Posts: 131
wiring harness on sl-600, ea motors
The wiring harness on the sl-600's and s-600's definitely are faulty. The insullation crumbles to dust. When the harness moves then wires touch and thigns in th eelectronics go crazy. the electric throttle actuators each have wiring harness attached to them that also fail.

Bosch made lots of bad wiring harnesses with 'bio-degradeable' insullation

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05-16-2002 06:07 PM

Robert Nelson
Junior Member

Registered: May 2002
Location:
Posts: 3
Gillybenztech Rocks
Gillybenztech was spot-on with the CTP Switch call. Seems to have been the culprit in other threads as well. Found by ohm meter test of pedal switch. S29/3 reading was 90k instead of .9-1.1. 30 miles so far without a problem. Will hold my breath for a week or so, and update, hopefully with some great 80 degree, sunshine, top- down driving experiences over this coming weekend. This forum is great. Copied all the posts related to ASR I could find to my dealer's service advisor, and I think it helped. By the way, instead of a bill for $5600 worth of dual throttle actuators, I left the dealer this morning driving my car after paying what I thought was a very fair bill. I am not sure if I should name the dealer on line, but Bryan, the S/A, and Don, who solved the problem, have my appreciation. If anyone with this problem can "limp-home" to Stockton, I know where I would suggest they go now to have the problem fixed.

amg280 · #13 06-15-2002, 01:03 AM

Where is the CTP switch located and what does CTP mean? Lately my 92 400E is going into limp home mode only when I depress the accelerater enough to click the kickdown switch behind this.

Any ideas?

-Andy

semi · #14 06-23-2002, 01:16 PM

I had same problem on my s500 95 ASR light was going off and car was loosing all power so I had to restart the car. None could find a problem I was told that is brake switch, gas filter, gas pump and in the end mechanic at MB dealer said that is 100% computer ($3000). I went home and tried my self and looking the accelerating cable (cable that goes from pedal to the engine) which when you press from engine side car loses power and ASR light goes off but by pressing pedal inside the car with your foot every thing works fine. i fond that it was cracked and very hard to see it. this cable is hard plastic and usually brakes near nut that is used to adjust the idle. I replaced it and had no more problems. Try by checking it maybe is the same one in your car.