M104, 2.8 Trouble Code 5

[pmizell]

... from my '94 C280. Bat Auto doesn't have codes for this engine listed .. anyone know what this code represents? I recently had EGR tube snaked due to blockage so not sure if this is related.

Thanks!

[manny]

I believe it is the EGR code ( not 100% sure ).
Was the code erased after having the tube cleaned?
Could be the EGR itself or, if vacuum-operated, the vacuum solenoid.

what i have determined is this is a 104.941 engine with HFM-SFI fuel injection, if that is correct code 5 is related to idle speed contact implausibility and has a couple of definitions, see picture below for actual code text. does the car have idle issues? all the code 5's are related to the throttle actuator, it is very likely that the harness at the actuator is baked and the insulation on the wires inside ane bare. does the cruise control work?

[pmizell]

Manny

Yes the trouble code has been erased twice from the diagnostic module, but has returned both times.

Ray

Thanks for that information ... the engine idles very smooth and seems to be in range both during warmup enrichment and normal operating temp. I haven't used the cruise control since I purchased car (3 months ago) but I'll go check that out and report. Where exactly is the throttle actuator located so that I can check the harness?

Thanks for the replies!

Originally Posted by pmizell

Manny

Yes the trouble code has been erased twice from the diagnostic module, but has returned both times.

Ray

Thanks for that information ... the engine idles very smooth and seems to be in range both during warmup enrichment and normal operating temp. I haven't used the cruise control since I purchased car (3 months ago) but I'll go check that out and report. Where exactly is the throttle actuator located so that I can check the harness?

Thanks for the replies!

unless you have a couple of thousand dollars handy i would't really advise you to mess with the harness, depending on it's condition you could make it worse. here is a picture of the actuator, it is the unit that incorporates the throttle valve.

[pmizell]

Thanks again Ray for taking the time to post the great information and visuals.

The cruise control works flawlessly. I have noticed, however that the engine's exhaust fumes are somewhat overwhelming when standing close to the car at idle. The car is averaging about 17mpg in city driving.

The ETA harness could be in the early stages of insulation deterioration as you mentioned so I think I'll give it a look by carefully opening up a portion of the sheathing.

I'll report back with more info and/or photos too.

Thanks!

[pmizell]

Well the cruise control did finally go out the other day and I immediately knew the culprit (Thanks Ray) as a repeated trouble code 5 blinked after being erased. I suppose this was inevitable given that this C280 has spent the first 100k of it's life in hot Florida, and now in Houston:



Anyone ever heard of these Throttle Actuators being goodwilled @103k miles? I'll rebuild it myself before I shell out $1,300 (dealer wants 2k) for a new one. Or I may send it to Beckmann for them to rebuild it if the price is decent.

What was the MB engineer that decided to use this wire insulation, thinking??

Arghhhh!

[deanyel]

Looks like all you need is a rewire. There's a thread somewhere on how to do that - someone must know where to find it.

[Arthur Dalton]

http://v12uberalles.com/throttle_actuator_rewire.htm

[pmizell]

Thanks Arthur, I have studied that DIY and it's an excellent tutorial however the connector on my EA is male unlike on the 120 engine, so I'm not sure how I would get that piece apart and if it's even possible to rebuild. What's encouraging though is that there's a part # on the side of the connector (140 540 37 81).

Would make this job a whole lot easier if MB sold this connector with unspliced wires coming out of the end.

I also found a UK company that will reman the unit for a very reasonable $500 w/2yr warranty in worst case scenario (http://BBA-reman.com). Anyone have any experience with these folks?

Thanks again all

[Arthur Dalton]

Yeah, I know..
just posted that to show what can be done on any of these things.. I always fix parts rather than replace if feasable and have found that all this stuff has ways of coming apart , be it with a saw , razor or whatever..
A servicable plug would sure be cool , though..

Sometimes the male ones are easier cuz you can unsolder the wires at the pins and pull them out ..

The rebuild guys prob have the plug source , but I doubt they are about to disclose that to us guys..

[JimF]

Originally Posted by pmizell

Thanks Arthur, I have studied that DIY and it's an excellent tutorial however the connector on my EA is male unlike on the 120 engine, so I'm not sure how I would get that piece apart and if it's even possible to rebuild. What's encouraging though is that there's a part # on the side of the connector (140 540 37 81).

Would make this job a whole lot easier if MB sold this connector with unspliced wires coming out of the end.

I also found a UK company that will reman the unit for a very reasonable $500 w/2yr warranty in worst case scenario (http://BBA-reman.com). Anyone have any experience with these folks?

Thanks again all

this company but check MENU#24 for some sources and the all-important feedback on these sources. Beckmann has excellent credentials and good feedback.

Be careful about "just" thinking it's the 'wire's?? It certainly is ONE of the main culprits in your case but . . . the Ref Pot could also be worn. There's no rebuilding of that part!

If you do decide to use them to remanufacture your ETA (Electronic Throttle Actuator), then let me know what kind of results you have. I've added this thread and the link to "BBA" into my "ASR" thread (Menu#24). Will post your results.