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1993 400E
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Discussion Starter #1 (Edited)
Hello all, I am new to the older Mercedes models. I used to have a w211 and then a w212 and now “upgraded” to a w124 as a midlife crisis/college days phase.

I have tried to do as much searching as I could and have come up with the following common failure points of the 400E.

1) upper wiring harness
2) lower wiring harness
3) throttle body?

I have read that #s 1 and 2 are a must if I plan to keep the car. Is #3 a must as well?

I am hoping that replacing 1&2 will solve my ASR light/limp home issue.

If #3 is a must, I might as well do it now and get it out of the way.

I do not have unlimited funds but if I am going to have someone work on it, might be more cost effective to get what is a must done all at once.

I live on Long Island/Suffolk county and my search has turned me to BMA Specialists. Anyone heard of them? Looks like they have good reviews? Any other suggestions in Suffolk County near zip 11787. I thought I saw another good shop in Smithtown/St James but I can’t seem to dig it up?

The plan is to have the shop diagnose the ASR situation and fix and do #1 and 2 and maybe #3.

Thank you in advance.

Andy
 

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'93 400e
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572 Posts
Yeah, common failure points for sure. If the harnesses haven't been replaced, they will need to be. Eventually the ETA (throttle body) will fail due to bad wiring as well if it's the old original one. If you or your mechanic need access to a new plug socket, I have a new one for '93 400E still in packaging I never used, since my mechanic had it replaced and re-wired elsewhere. Check the for sale section of this forum if interested.
 

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1995 E320 2 Door Coupe 98,000km
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Yeah, common failure points for sure. If the harnesses haven't been replaced, they will need to be. Eventually the ETA (throttle body) will fail due to bad wiring as well if it's the old original one. If you or your mechanic need access to a new plug socket, I have a new one for '93 400E still in packaging I never used, since my mechanic had it replaced and re-wired elsewhere. Check the for sale section of this forum if interested.
Far too many of the w124's burned up in their driveway due to that bio degradeable engine harness. Until you get the new harness installed I'd recommend you disconnect the battery when not in use to prevent a destructive fire. As for the ETA, it has a rotted cable harness too. The ETA has a 16" long cable that is soldered to the internal circuit board. The other end is a plug connector. Replacing just that harness is too labor intensive. Also, deep inside the ETA there is coil that is energized by the ECU so that it can take control of the butterfly valve for cold start and cruise control. That coil burns open and is a common failure. Replacing that coil requires grinding out the shaft lockwasher and a TIG tack weld to put it back. Been there done that so trust me..... find a new ETA with new harness. A used ETA could still have a rotted cable harness so be careful. Fuel pumps don't last for ever so listen for noisy/whining pumps. The CKP(Crank Shaft Sensor) is prone to failure.
If the blower motor fails, the fuse is separate from the fuse block so don't assume the motor has failed. I have a 1995 E320 2 Door Coupe and these are the problems I have encountered. Repairs are not that difficult. Welcome to the wonderful world of the W124. They're awesome cars!!!
 

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'93 400e
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Frankly I haven’t had my lower harness replaced and right now I’m not worried. If you had to pick one to wait on, I think that would be the one.
 

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Not sure I have ever heard of a w124 turning into a bbq because of bio junk harness deterioration... but crazier things have happened I guess!

Anyways, for the ETA, search for Don Roden on ebay. He rebuilds them, and is snappy quick about it. Highly recommended.

Jono at blue ridge mercedes is your best bet for the lower harness, its NLA, but he can rebuild em.

Upper harness was still available from MB last I checked.


Sent from my iPhone using Tapatalk
 

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1993 400E
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Discussion Starter #7
Thank you for all the info.

What does ETA stand for? I’m guessing electronic throttle actuator?

Any other feedback? I’m taking it to BMA tomorrow.

Thanks,

Andrew
 

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'95 E300 DIESEL, '91 600SEL, '92 600SEL
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Yes, ETA is Electronic Throttle Actuator. Be aware that the entire car is made from eco junk wiring, but the most notorious ones are the main (upper) engine harness and the throttle actuator.

Without replacing those components to ones made 1998 or newer, these cars cannot be reliably troubleshot.

When replacing you MUST get identical parts by matching & verifying part numbers. Substituting a throttle actuator from a NON ASR vehicle will not work even though they look roughly identical.

The lower harness WILL eventually go, but you will get plenty of notice such as erratic oil pressure readings, false oil level warning light, etc.
 

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1993 400E
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Discussion Starter #9
Me again:

I called BMA and they say they are not familiar with this year/model. I’m glad they were honest about it.

Back to square one.

Anyone have any recommendations on Long Island, NY. Specifically Suffolk County.

Thanks,

Andy
 

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1993 400E
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Discussion Starter #10
Trying to locate part numbers:

Upper harness: is this the part number? 1244401906

ETA is this it? 0001417825

Lower harness: is it? 1245403130

Thanks
 

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SL's & 500E's
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Do yourself a huge favor, simply call Victor at Restore your Mercedes.com


He is working now out of his house on City Island, not that far from anywhere on Long Island. I live 75 mile north of NY City, and drive down to him for all electronic issues. He is an expert on all the electronics and restoration of these model cars.
Victor will rebuild your ETA as well as repair/replace bad cables as needed. He has worked on all 4 of my 124's, reasonable prices, and always fixes whats needed, and doesn't waste your time or money, very honest guy.

Oh by the way, there is a 4th item, the Egas module also can contribute to ASR failures. On one of my 500E's I recently had to buy and install a new Egas module to cure an intermittent ASR problem. (All cables and ETA were previously done).

I can't recommend Victor enough, he knows everything about 124's and can fix everything.

Go to YouTube as well, search for restore your mercedes, he has lots of videos of his repairs there..





good luck...
 

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'95 E300 DIESEL, '91 600SEL, '92 600SEL
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I'm not a fan of reman'd a.k.a. rewired throttle bodies. I've never seen one go more than about 5 years before they start acting up.

My pref is to find good used non eco junk donor parts. Anything 1998 and up is fine, although newer is better for obvious reasons.

Regardless which way you decide to fly, be sure to install a new throttle body gasket with a new factory piece whenever the throttle body is removed to eliminate the chance of a vacuum leak.
 

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1993 400E
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Discussion Starter #14
gave victor a call. Left a voicemail. It’s 55 miles from me though. Can I limp that far? Without causing more damage?

My local guy said he does not have a code reader that goes back to 1993. so he won’t even attempt it. How much are code readers? Maybe I can get him one?

I have to keep working on options.

Will hit the phone lines tontry and find someone closer while waiting for victor to call me back.

Any thoughts?
 

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SL's & 500E's
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gave victor a call. Left a voicemail. It’s 55 miles from me though. Can I limp that far? Without causing more damage?

My local guy said he does not have a code reader that goes back to 1993. so he won’t even attempt it. How much are code readers? Maybe I can get him one?

I have to keep working on options.

Will hit the phone lines tontry and find someone closer while waiting for victor to call me back.

Any thoughts?
Yes, Be patient and call Victor back, who knows if he is on vacation or just away for a couple of days.
The recommendation I'm giving you is from personal experience, not just guessing or assuming anything.
Victor has very many happy customers, someone else's 5 year problem did not come out of Victors shop.
You are not going to find anyone else with as much specific and total knowledge of these cars.
All I can do is point you in the right direction, you need the patience and will to persevere.
 

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1993 400E
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Discussion Starter #17
Trying to locate part numbers:

Upper harness: is this the part number? 1244401906

ETA is this it? 0001417825

Lower harness: is it? 1245403130

Thanks
Stupid question: I assume my car is the ASR model since I have the ASR indicator on the dash and it has come on intermittently, hence this thread.

If so my part number for the ETA is wrong as I think that is the non-asr model.

The asr model, based on my research is 0001417925

Can anyone corroborate my numbers?

Thanks
 

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SL's & 500E's
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I have the same numbers you have. Using my 94 E420 vin, and checking on the new Mercedes online parts portal, these are the PN's below- (I think 93's are the same, but using your vin # would confirm that). About 5 years ago I replaced both cables with new OEM ones, and replaced the ETA with rebuilt one. No problems since.

ETA - A 000 141 79 25
Upper harness - A 124 440 19 06
Lower harness - A 124 540 31 30

I think the upper harness and the ETA are still available, but the lower is NLA, used or rebuilds are around.
 

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Buncha W124's
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I have tried to do as much searching as I could and have come up with the following common failure points of the 400E.

1) upper wiring harness
2) lower wiring harness
3) throttle body?

I have read that #s 1 and 2 are a must if I plan to keep the car. Is #3 a must as well? I am hoping that replacing 1&2 will solve my ASR light/limp home issue.
Andy, #1 and #2 have NOTHING to do with limp mode. Nothing. You need to pull codes from the E-GAS module (which controls the ETA / throttle body) and see which codes are causing the limp mode. The most common cause is the neutral safety / gear position switch (NSS) on the transmission, followed by the ETA or the switch behind the gas pedal, and least likely would be a faulty E-GAS module. This assumes the throttle linkage is adjusted correctly.

Also, you can easily check both wire harnesses to see if they are original or not. Many upper harnesses have already been replaced by now, there is a date code on the tag near the CAN box. Lower harnesses are rarely replaced so that's less likely; but unless all the insulate is falling off behind the alternator, you can delay that for the moment. The ETA is harder to tell since there is a date code, but if the original was rebuilt, it would have an old date code. And there's no guarantee that newer ETA's are "good". I'd highly recommend poking around the tech section of 500Eboard, since ~99% of the 500E powertrain / diagnostic information will apply to the 400E. With a hand-held blink code reader you can handle a lot of DIY repairs yourself, including the infamous limp mode - which is not nearly as much of a big deal as many people think.



I have the same numbers you have. Using my 94 E420 vin, and checking on the new Mercedes online parts portal, these are the PN's below- (I think 93's are the same, but using your vin # would confirm that). About 5 years ago I replaced both cables with new OEM ones, and replaced the ETA with rebuilt one. No problems since.
ETA p/n 000-141-79-25 is for 1992-1993 USA model years only (with ASR). The connector is different on 1994-up models; which use p/n 000-141-94-25. The EPC shows an engine number break which is incorrect; it indicates the newer style began in late 1993 production, but it did not... all evidence points to the break point being the body facelift.



I think the upper harness and the ETA are still available, but the lower is NLA, used or rebuilds are around.
The upper harness is still available new, p/n 124-440-20-06 for 1993-95 models, ~$375 delivered from MB of Naperville with a promo code for free shipping. Takes about an hour to replace. The lower harness is NLA but Blue Ridge MB in Atlanta rebuilds them. The ETA is available from MB for $2200 list / $1700 discount, or you can have Don Roden at RFC Electronics rebuild it for a fraction of the cost (~$350), and no he doesn't just replace the external wires. Victor might rebuild them as well, I'm not sure if he does it in-house or sends them out.


Far too many of the w124's burned up in their driveway due to that bio degradeable engine harness. Until you get the new harness installed I'd recommend you disconnect the battery when not in use to prevent a destructive fire. ... Welcome to the wonderful world of the W124. They're awesome cars!!!
The 124 chassis are awesome cars, but they do nut burn up in the driveway due to the biodegradeable engine harness. I've actually never heard of that happening even once. Now, the high pressure fuel hose between the filter outlet and the fuel pipe... those are prone to leaking, and those HAVE burned cars to the ground, since the leak is right next to the exhaust. Click here for detailed info on hose replacement. If the pumps are original I'd consider replacing everything at once. The pumps are usually worn out after 25 years; ~$200/pair for new Bosch.


The biodegradeable engine harnesses (and ETA) can last a VERY long time if the wires are undisturbed. Our 1995 E420 had over 200kmi on the original harnesses and ETA with zero issues, until it met an untimely demise due to some muppet on the phone who rear-ended stopped freeway traffic at 65mph. I had picked up good harnesses to install when the old ones finally caused problems, but never needed them. We replaced that car with a '94 E420 which is still on the original harnesses at 150k. We have a different '95 E420 at 240k where a PO had already replaced the upper harness and ETA, but the lower is still original.

YMMV, etc...
 

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Buncha W124's
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Stupid question: I assume my car is the ASR model since I have the ASR indicator on the dash and it has come on intermittently, hence this thread.
Forgot to mention, I assume you know the triangle light in the speedo flashes when ASR is active / detects wheelspin.

The "ASR" warning light below the tach will illuminate if the ASR system is non-functional, which may or may not be accompanied by limp mode. If the warning light and/or limp mode are intermittent, you can further diagnose by clearing all fault codes on the E-GAS module, then checking codes frequently to see which return. Use the PDF at the link below to look up the codes:


:cool:
 
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