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1984 W123 240D; 2001 E220 CDI W210; 2012 E250 CDI Bluetec - Avantgarde; 1994 SL320
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262 Posts
Discussion Starter #1
1994 SL320 - Has Throttle body with ASR functionality.

Car generally runs well. No freak ASR lights showing up whilst driving baring the following 3 episodes:

1. Bought car which was lying static for several years. Whilst replacing intake manifold gaskets and other related gaskets ASR light showed up and car would go into limp mode. Cleaned out throttle body internal circuit board which had some oxidation between solders at back. Results - no ASR light, car idle settled to 450/500 rpm. All well

2. A year on and a few thousand Km's later, the crank shaft upper breather pipe sprung a leak and ASR light on/Limp mode. replaced pipe, and ASR light did not go immediately. Fiddled around with pipe and somehow ASR light went off and car was back to normal. All well.

3. A year later and car now running well/consistently. Engine wiring harness was overdue for new wires. Replaced all wires done by my competent wiring man (MB dealership unable to provide manufacturing date on new delphi harnesses, so opted for self rebuild). All new wires baring throttle body and ASR ( they looked intact externally). After putting everything back together (reassembly) ASR light comes on, car holding high revs 1000+ (not settling to idle) and revs increasing if accelerator pedal pushed (given gas). When driving car would not change gears unless foot taken of the pedal. We decided to inspect throttle body wires and ASR wires..both we buggered (degraded) inside. Throttle body and ASR wires replaced, now car still has ASR light and in limp mode, but revs on start at 450/500 and settle at 1000. car refuses to rev up/revs and revs are abruptly cut at 1500-2000 rpm. Car will not shift gears beyond 1st gear and refuses to really accelerate beyond 1500-2000 rpm then seems to kinda misfire and or cut out power!!

My mech suggests I get another throttle body and says nothing wrong with ASR.

Scanned car with handheld basic pulse scanner.

Socket 6 shows 30! although not consistently. (Error code 30 is ASR only CAN date bus to EA/CC/ISC control module, interrupted). Error 30 is for 1995 model and mine is 94 and the error code sheet ends at 29 for 1994 models confused as hell!!

Socket 7 shows error code 2 (EA/CC/ISC control module (N4/1) or Safety contact switch (M16/1s1) or Stop lamp switch or Cruise control switch or Actual value potentiometer or Starter lock-out/back-up lamp switch or engine speed signal or vehicle speed signal or closed throttle position switch or safety relay in EA/CC/ISC control module)

ASR/Throttle body sages/gods...what is the verdict? get a new throttle body? OR ?

Thanks
 

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2000 SL500
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352 Posts
This place may be be a good source of information. If it were me I would contact them with all the information you've provided here and see what they say. The one big unknown is the problem started right after the wiring harness rebuild so the wiring harness has to be suspect and it will make it more difficult for this place to diagnose or guarantee what can be done on their end. It does look like they have good experience with the problems you're seeing though.

 

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Registered
1984 W123 240D; 2001 E220 CDI W210; 2012 E250 CDI Bluetec - Avantgarde; 1994 SL320
Joined
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262 Posts
Discussion Starter #3
This place may be be a good source of information. If it were me I would contact them with all the information you've provided here and see what they say. The one big unknown is the problem started right after the wiring harness rebuild so the wiring harness has to be suspect and it will make it more difficult for this place to diagnose or guarantee what can be done on their end. It does look like they have good experience with the problems you're seeing though.

Thank you for your input, yes we are giving the new wiring job a detailed once over today. Fingers crossed, hope it's just some new rewiring mistake. Since the Throttle body was working fine before this job maybe we find a wiring fault!! Otherwise it's going to be a throttle body rebuild or parts replacement i guess...
 

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Registered
1984 W123 240D; 2001 E220 CDI W210; 2012 E250 CDI Bluetec - Avantgarde; 1994 SL320
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262 Posts
Discussion Starter #4
Update- cleaning out the throttle body including carbon deposits at potentiometer has yielded/rendered the throttle body operating fully, as in car accelerates/revs to full rpm and ASR doesn't cut in or car doesn't go into limp mode. But idle RPM was at 1400 which my guy clams has been now "adjusted" to 600.

But the ASR light has not gone!

Will attempt doing a scan cum reset via my pulse scanner today! And an investigation of the ASR system whatever that means. Not sure what to look for in ASR!!

Any inputs on this would be most welcome!

How does one know if brake light switch etc is bust. My lights work. What else is there to look into ASR
 

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1993 Sl 500
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460 Posts
When I first got my 1993 SL500 the ASR used to intermittently cut in when driving out of a junction but I have the Star Chinese clone and it came up with a faulty ASR switch which is under the throttle pedal, easy to change and was about £50-60.
 

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Registered
1984 W123 240D; 2001 E220 CDI W210; 2012 E250 CDI Bluetec - Avantgarde; 1994 SL320
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262 Posts
Discussion Starter #6
Thanks guys issue sorted, apparently a clutch type mechanism inside the throttle body would not engage completely! the entire throttle body was pulled apart and cleaned any carbon cleaned out. The ASR light went of immediately after the throttle body was installed and car seems to run fine now.
 
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