zerocover

So today my car threw its first check engine light.

I grabbed my OBDII reader (ELM327 ie universal) plugged it in and fired up Digimoto. As I had some many times before on all my cars.

When I did this on the Benz the diagnostic came up that my scantool wont communicate with the engine. (mind you it does some basic communication with the car)

So I cant check my codes.

I tried using the port under the steering wheel. Are there any others that I should be aware of? Possibly one in the engine bay that might work?

bdgdl08

That's odd. I have used an OBDII reader from an auto parts store (borrowed) and it worked fine for me to both read and clear the code. Good luck.

ontmiss

Port under steering wheel is right one. Works for me, make sure you key is in ignition position 2

zerocover

I found the problem, the I hyper-terminated into the car, and asked it "what are valid commands"

It responded back, in German and basically told me I'm SOL.

When I connect to my mazda it responds back in English not japanese, when I connect to my volvo I dont get bork bork bork I get English (and its very polite). So it looks like Mercedes uses its own interface, IE I need a mercedes compatible program to communicate with it. It might be that standalones have this modified language, but I dont.

Anyone else have luck with a PC based OBD connection? What program did you use?

DangTH

I use ELM 327 and it work fine with any program eg. PCM Scan.
It use KWP fast protocol for communication with C200 ECU ( engine M111+Kompressor )
Try adjust communication protocol and also correct baud rate.

zerocover

I just tried PCMscan, I get connection established on COM4, no connection to car make sure key is in on position etc... Mind you I have my key in position 2 or the car turned on.

In other news my check engine light has mysteriously gone away, but I still want this thing working.

I need to look up the specifics of the KWP protocol now.

DangTH

You must turn the key to the position before starting or engine started.
As I recall, we need to adjust com port buffer size to be smaller.
Go in setting --- control panel ---- system ----hardware ----device manager
select com port ---- port setting ---- advance----and adjust buffer size.
This is for Windows XP. Hope this help.

KalC240

'02 c240 89K miles

The check engine light (and the yellow triangle with !) came on this morning and stayed on for about 3 miles. Then coming back home, the CEL was off.

Used the innova 3130 scan tool but there were no codes stored, not even pending codes. It shows green light emission status.

Any ideas wahy there are no codes if light was on for three miles?

Glyn M Ruck

Software/firmware brain fade - it happens. Clears on a reboot by stopping & restarting the car generally. Don't worry about it unless it happens again.