parnelltk

1992 400E with 196K Miles

I have searched hard and been unable to find the clear path on a Diagnostic Trouble Code (DTC) Reader (making one (DIY) or commercial), or reading the blink codes.

Please Clarify or Confirm:
After 1996, you can apparently pull all the Codes with a Scan Tool? Shops and Auto Stores that promise a free scan seem to limit to Post-1996 Models

For my 1992 400E and other models before 1996, what are the options for reading and clearning the Codes?
Does reading the Blink Codes give you the same info as any commercial scanner for 1992 400E?
If a Scanner gives more info, what does it give you additional?

Where do you find the meaning of each Code?

After Getting all the Codes, how do you finally easily clear the Check Engine Light (CEL)?

If you experts can give me some insight on this today, I will be eternally greatful. I have to complete my California smog check and just realized I am going to be late if not done today.

Any other great tips for passing smog on a 1992 400E, 4.2L V8?

Thanks folks!!

parnelltk

1992 400E Mercedes-Benz with 196K Miles

Come on Experts, I have to get the smog check before closing time today. Give me a few tips while you are watching football, OK?
Thanks,
Kim

parnelltk

1992 400E 196K Miles - CA Smog Check FAILED at IDLE

I figured out again how to pull the diagnostic LED blink codes.
I got 3 codes:
2
21
26
After clearing each code, I then wound up having to disconnect the battery for several minutes to get the Check Engine Light OFF. Is there another way?

I also attempted my CA Smog Check yesterday. I really warmed the car up thoroughly with about 20 miles of high-speed and some low-speed driving.

It failed on Hydrocarbons (HC) at Idle:
Measured HC 197ppm vs. Max Allowed HC 120ppm (and avg. 29ppm)

So I am very high on Idle HC and looking for most effective things to check and repair to pass right away.

Overall the car runs well and idles smoothly.

Spark plugs, Wires, Rotors, Caps are about 30K miles old. I do not see that as old enough to replace (visually wires etc are in good shape). Other opinions on replacement interval for these items?

What else?
Catalytic converter is fairly old. Is the Catalytic Converter a big factor on HC?
Catalytic Converter is also very expensive - I am told $1000??

One mechanic has told me that for about $150, he will "clean something" and it will pass. He says "you do not need to know what I clean!!"

Is there any possibility this mystery cleaning could work??
Urban myth?

I would really appreciate some insight and advice from the Experts here!

Thank you.

biker349

if he won't tell you what he's cleaning i would get another mechanic. could be maf, filters? i believe you can tell if the catalytic converter is bad by hitting it and seeing if there is a rattling noise which might indicate a bad converter.

parnelltk

1992 400E 196K Miles - CA Smog Check FAILED at IDLE with high HC

Thanks for the Reply.
So hit the Catalytic converter to see if it sounds like the shell or insides are damaged?

Can the Catalytic Converter definitely pull down the high HC readings?

vexed

Look here. Everything you need on how to build and use a code reader

http://www.k6jrf.com/MB_X11.html