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?

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.

[arif]

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.

[Gilly]

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

[Kebowers]

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

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.