How do newer Honda and VW Diesels comply with OBD2? Or do they not have to? If they do, there must be some interesting concepts in making OBD II talk to a Diesel..

All cars sold in the US market since 96 are required by law to be OBDII compliant. Diesels are no exception.

My 99 will trigger hundreds of different engine codes. If you add in tranny, SRS and a zillion other MB proprietary systems the list would be well over 1000.

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Terry Allison
N. Calif. & Boca Chica, Panama

09' E320 Bluetec 77k (USA)
09' Hyundai Santa Fe Diesel 48k (S.A.)

SDS is a grand thing.

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1999 SL500
1969 280SE
2023 Ram 1500
2007 Tiara 3200

My '96 E300 does have the OBD-II port, but this really doesn't tell you much at all. The only emissions tests reported are the comprehensive and EGR. The injection is completely mechanical with electrical rack modulation, so there's not much that can be reported. To find out about the rest of the car, you have to plug into the diagnostic port under the hood.

Our '06.5 Jetta TDI also has the OBD-II port which speaks CAN. A generic CAN-capable code reader will read the emissions and engine codes, but with a special scanner a lot of data and settings are available. Injection timing, for one. I've read that you can even fine-tune the power steering assist level through that port (not that it needs it).

Here in Washington state, 96 and up Diesels under 8500gvw are tested
using the ASM dyno and opacity method.
They do not scan them for OBDII codes like a 96 and up gas car.
If the Diesel has traction control or is awd they will use the old "snap test" method to check opacity.

DR.D

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Dr.Diesel -
Shop Foreman
Master Guild Mercedes-Benz Technician.

Think the dealer is expensive? Do you know how much it costs to train a dealer tech? Or buy the required MB special tools to have on hand?

Dr. Diesel - being new to Puget sound, couple of questions...
my 99 E300 TD just failed emissions this morning with 43%(!) opacity. Could this possibly be correct? Engine was properly warmed up when I took the test. I am bringing to dealer tomorrow to have "certified diesel inspection" that state requires. Maybe something truly is out of whack, though the car seems to be running fine and economy has stayed steady at about 26 mpg. Also, any recommended MB diesel service folks in this area? I'm looking for a reliable indy with a fair labor rate. Thanks!!

I used to live in the Puget Sound Area. I have to ask, what shape is your airfilter in? A dirty air filter in a humid winter climate like Seattle will definitely affect your emission test results about now!

Here's a cool device a lot of TDI folks are using...
http://www.scangauge.com/

If I decide to hang onto my TDI I'm going to pick one up. Unless you have a lot of those features built-in, I'd recommend Scan Gauge II to anyone with OBDII.

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-justin

1987 300TD, 1987 300TD
2008 R32, 2000 Passat Wagon