I bought the universal code reader from Harbor freight ($39.99), item # 46030. I tried reading a check engine situation on a 1996 SL320. It was unable to pull the code. Then i tried with an Actron 9135 and it read the error code (P0441). Harbor Freight tech support told me that their reader can only read universal or generic OBDII. Not sure why the Actron (non proprietary) would work but not the HF one.

I am looking into the Actron CP9145 which also allows reading live streaming data. I might buy that one.

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1972 450SL
1982 300D Turbo

My 96 SL320 gave me the same code, it is purge flow pressure. I replaced the purge valve and the check engine light has never came on again. (6 months) With the MBCA discount I got my new Purge valve for $96 at the dealer. Shop around, they are not cheap. Good luck!
Brian

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Brian W. Heitman

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Thanks for that info brian. Would there be any harm in not replacing the purge valve?

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1972 450SL
1982 300D Turbo

Well,
with my car I didn't have a code reader at first, and when the engine light would come on I would disconnect the battery and reset. I finally saved my pennies (got permission ha ha) and bought a scanner. I drove it that way for about a year because I didn't know what was wrong. The P0441 code just says it is incorrect purge flow pressure, so when I got the code I checked everything in that system, It could be a vacuum leak or loose hose, bad gas tank cap etc.. All of these things contribute to the problem. I tested my purge valve and it would not even click, they are supposed to make a clicking noise when activated, I just put 12 volts to it and nothing happened. I then knew that the purge valve was bad. I don't think it will hurt the car to drive it, however you should be extra careful of the pressure in the tank, and it may use more fuel since the purge valve opens and allows the intake vacuum to pull gas fumes from the charcoal cannister to burn in the engine, without it you are not getting the use of your fumes. This is basically an emission system so that you don't expel gas fumes into the air, rather burn them up in the engine and through the catalyst minimizing the pollution, so it will probably be ok that way, but here in Texas my car would not pass inspection unless it was repaired. The purge valve is electrically operated and is located in front of the ABS pump, it has a line coming from the firewall, (Charcoal cannister in trunk on 129) and then a line going to the intake manifold, both black plastic, and the valve itself says "MOT with an arrow pointing to the motor output side" Happy Benzing!
Brian

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Brian W. Heitman

www.MBCA.org/northtexas

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Oh,
I have posted the system function and locations here http://www.mbca.org/northtexas/vacuum_pneumatic.htm

Take a look, you will see where everything is located and know where to look to check it out. I hope this helps.
Best Regards,
Brian

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Brian W. Heitman

www.MBCA.org/northtexas

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Purge valves are easily cleaned with WD40. I also squirt some in the hoses and let the vacuum suck it through the valve..
If the valve is funtioning , you can feel the frequency beats with the valve in your hand . They just get dirty from fuel emiisions and stick open/closed.
If stuck closed , they do not allow flow, but if they stick open, then they create an internal vac leak and will raise hell with fuel trims. Many an unfound vac leak is simply a stuck open purge valve..

They use a rapid on/off feature so the engine does not read lean/rich by gulping all the air at one cycle. It should come on after 70C.............

Wow! Thanks Aurthur, I didn't know you could clean them, I wish I would have known that before I bought a new one. That is some good information!
Thanks again,
Brian

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Brian W. Heitman

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B,

.. yeah, they just get gunked up from old gas fumes and dirt..
I always just cup them in my hand when the car is warm and running just to feel for the pulses/beat... I do that whenever I suspect a vac leak cuz I know they will fool ya if not working and it only takes a second to diagnose that way... some of the early ones you could hear clicking open/closed..

I'm looking to buy a code reader. Anyone have any recommendations? Found a website that recommended this one:http://www.jcwhitney.com/autoparts/Product/showCustom-0/Pr-p_Product.CATENTRY_ID:2009348/c-10101/Nty-1/p-2009348/Ntx-mode+matchallpartial/N-10101/tf-Browse/s-10101/Ntk-AllTextSearchGroup?Ntt=eqqus

Anyone have any experience with it?

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

That is the same exact one I got, mine was from Pep Boys for $89.00 It came with a manual, but generic. I was lucky enough to find a M104 Engine diagnostic manual from a fellow MBCA member. This will only read generic OBD II codes, so things like the SRS system and other proprietary MB controls can not be read and reset with this reader. Good luck!

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Brian W. Heitman

www.MBCA.org/northtexas

Join MBCA!!!

I noticed that on your signature that all your cars are pre-1996, this OBD II reader will only work with 1996 or newer. Just wanted to make sure you knew that!
B

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Brian W. Heitman

www.MBCA.org/northtexas

Join MBCA!!!

Not only are they pre-96, they're all pre-computer! I'm looking at buying a motorhome with a 99 5.9 24v Cummins which is computer controlled.
The info on the Eqqus states that it reads generic and proprietary (p1) codes. Perhaps that is the difference between the 89 and 129 models??

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13